Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
453 AM AST Sun Apr 27 2025

.SYNOPSIS...

An unsettled weather pattern is expected to continue through
midweek. A high rip current risk is in effect for the northern
exposed beaches of Puerto Rico, from Aguadilla to Fajardo and
Culebra through at least late tonight.

&&

.SHORT TERM...Today through Tuesday...

Radar and satellite imagery showed cloudy skies across the islands
during the overnight period. Some showers moved into eastern
municipalities, with the highest rainfall accumulations reported in
Fajardo, ranging from around 1.0 to 2.0 inches as of 4 AM AST, based
on radar estimates. Numerous showers and thunderstorms persisted
through the night across the Caribbean waters. Surface weather
stations registered light winds, mainly from the east. Overnight
temperatures ranged from the lower 60s in the mountains to the mid-
70s across urban and coastal areas of Puerto Rico and the U.S.
Virgin Islands.

The forecast remains generally on track. A wet and unstable weather
pattern is expected to continue through the forecast period across
Puerto Rico and the U.S. Virgin Islands, bringing periods of heavy
showers and thunderstorms enhanced by the presence of a deep-layer
trough and above-normal moisture. Based on the latest model
guidance, moisture content is expected to peak today between 2.0 and
2.1 inches, which is above climatological levels for this time of
year. Although mid-level clouds may slightly limit convective
development, the available moisture and prevailing instability will
still favor afternoon thunderstorms, especially over interior and
northwestern Puerto Rico, as winds are expected to shift from the
east to southeast during the day. Soils remain saturated from recent
heavy rainfall, so the flood risk will stay elevated, similar to
yesterday, as soils and rivers may respond quickly. Potential
impacts today include lightning, strong winds, heavy rainfall,
landslides, and river flooding. Isolated flash flooding cannot be
ruled out.

In the coming days, the wet pattern is anticipated to continue under
the prevailing influence of the trough. Although moisture content
will slightly decrease, it will remain in the above-normal to
average range maintain the wet pattern, with strongest activity
mainly during the afternoons. Winds will turn more form the east to
north east from Monday night onward shifting the afternoon
concentration of showers and thunderstorms a little more to the
southeast of the main island. Residents and visitors are encouraged
to stay weather-aware and monitor official forecast updates,
especially due to the ongoing flood risk, which remains the primary
hazard.

.LONG TERM...Wednesday through Sunday...

A wet and unstable weather pattern will persist through the early
part of the long-term forecast. A surface high-pressure system over
the western Atlantic and a surface low over the central Atlantic
will induce east-northeast winds across the CWA. These northeast
winds will promote low-level convergence over the region,
particularly on Wednesday and Thursday, when the surface low will be
closest to the northeast. Precipitable water content is expected to
remain between 1.7 and above 1.9 inches. These values exceed the
75th and 90th percentiles of the climatological normal, indicating a
continuation of well-above-normal moisture levels for this time of
year.

In terms of instability, the surface low is being induced by an
upper-level cut-off low. These features will lead to a further drop
in 250 mb height fields, cooler 500 mb temperatures, and steeper
lapse rates, sustaining unstable weather conditions capable of
generating deep convective activity. The likelihood of convection
will be highest during the afternoon hours, as high moisture content
and instability combine with surface heating and local effects.

Soils are expected to remain somewhat saturated by Wednesday due to
rains from previous days, with rivers still experiencing elevated
streamflows. Consequently, the flood risk will remain elevated
through at least Thursday, particularly during the afternoon hours.
Quick river rises, river flooding, and landslides are also possible,
primarily across Puerto Rico. In the U.S. Virgin Islands, minor
flooding with brief periods of excessive runoff is possible each day
of the week. Some ridging aloft will bring somewhat more stable
weather conditions by the end of the workweek into the weekend.
Nevertheless, enough low-level moisture could combine with diurnal
heating and local effects during the afternoon to promote convective
activity in localized areas.


&&

.AVIATION...
(06Z TAFs)

VFR conds across most western TAF sites this morning. -SHRA/VCTS
across TJSJ and likely USVI TAF sites may result in intermittent MVFR
conds and reduced VIS trough the morning hours. SHRA are expected to
develop after 15 to 16Z across the Cordillera Central, spreading
toward the west/northwest. Mtn top obsc likely through 27/23z. Winds
will prevail btwn 5-10 kt with higher gust within t-storms. Mainly
from the ESE with sea breeze variations today, becoming from the E
tonight.

&&

.MARINE...

Light to moderate east to southeast winds will prevail through at
least tonight, backing from the northeast winds early this week. A
deep layer trough will continue to promote an unstable weather
pattern across the local waters. Thus, showers and thunderstorms are
expected to persist, producing localized hazardous marine
conditions. This unstable and wet pattern will prevail through at
least midweek. A long-period northeasterly swell is spreading across
the Atlantic waters. Therefore, small craft should exercise caution.


&&

.BEACH FORECAST...

Nearshore buoy 41053 is already detecting 13-14s pulses of the weak
northerly swell. As a result, a Rip Current Statement continues in
effect for the northern beaches of Puerto Rico, from Aguadilla to
Fajardo, as well as the beaches of Culebra.

For more information, please refer to the latest Coastal Hazard
Message (CFWSJU) and Surf Zone Forecast (SRFSJU).

Residents and visitors in affected regions should heed warnings,
avoid swimming in these waters, and stay informed about updates from
local authorities.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
509 AM AST Mon Apr 28 2025

.SYNOPSIS...

An unsettled weather pattern is expected to continue through at
least Thursday due to a series of troughs and abundant moisture.
The likelihood of urban and small stream flooding due to strong
showers and thunderstorms, as well as mudslides and rapid river
rises, will remain high along with a chance of isolated flash
flooding as well. A high rip current risk remains in effect for
the northern exposed beaches of Puerto Rico, from Aguadilla to
Fajardo and Culebra through this afternoon.

&&

.SHORT TERM...Today through Wednesday...

Shower and thunderstorm activity that had been impacting the
municipalities of Arecibo and Barceloneta ended close to midnight,
leaving nearly 8 inches of rain in the northeasternmost tip of the
Arecibo municipality, with other areas receiving 4 to 6 inches. The
rest of the night was much calmer compared to the afternoon and
evening hours, with moderate showers occasionally moving over St.
Thomas. Minimum temperatures were mostly in the low to mid-70s
across coastal areas of the islands and in the mid to upper 60s in
the highest mountains and valleys of Puerto Rico.

Current satellite imagery and GLM data show that the most active
part of a deep-layered trough is located north of Puerto Rico, over
the offshore Atlantic waters, where the trough is exhibiting the
strongest low-level convergence and upper-level divergence. GOES-19
Precipitable Water satellite data continues to show well above
normal moisture over the region, particularly upstream of the local
islands. Therefore, during the rest of the morning hours, showers
and isolated thunderstorms are expected over the regional waters,
with some showers occasionally moving over windward coastal areas.

Winds will begin shifting today from southeasterly to easterly, and
then to a more northeasterly direction by Wednesday, as a surface
high pressure over the western Atlantic gradually pushes a frontal
boundary associated with the upper-level trough closer to the CWA.
The combination of above-normal moisture, instability aloft, diurnal
heating, and orographically driven convection will lead to another
active afternoon, with thunderstorms first developing over interior
Puerto Rico. The steering wind flow is expected to remain light
throughout most of the short-term forecast period. As a result, slow-
moving thunderstorms will initially cluster over the Cordillera
Central and may later move toward coastal areas as outflow
boundaries generate new convective cells. A similar weather pattern
is expected on Tuesday.

However, Wednesday appears to be the wettest and most active day, as
the aforementioned trough deepens and develops into a cutoff low,
closing off by the end of the forecast period, particularly by
Wednesday night. Widespread thunderstorm activity may develop, and
if it occurs during the evening and night hours, another round of
heavy showers and thunderstorms could impact the eastern third of
Puerto Rico, including Vieques, Culebra, and the U.S. Virgin
Islands. As a reminder, soils are already saturated, and streamflows
are running well above normal due to heavy rains over the past
several days. Therefore, urban and river flooding is likely to
continue, along with the potential for flash flooding and landslides
in flood-prone areas and steep terrain, respectively. Continue to
monitor the forecast as this unstable weather pattern persists
across the region.

&&

.LONG TERM...Thursday through Monday...

The long-term forecast continues on track, with a variable and
unsettled pattern ahead. The interaction between a high surface
pressure in the Western Atlantic and a surface low induced by an
upper-level trough will promote light NE-E winds through the period.
Global model ensembles agree that Thursday will be the wettest
day of the forecast period, suggesting above normal Precipitable
Water (PWAT) values (around 1.75 inches). Colder 500 mb
temperatures (-8 to -9 Celsius) and jet dynamics around 250 mb
with speed near 70 knots will bring ventilation and instability
aloft, supporting deep convection activity. As the mid to upper
level trough migrates eastward, drier air will filter into the
region, inhibiting deep convection activity. Additionally,
temperatures in the 500 mb layer should increase to seasonal
values (around -7 Celsius). Although global model ensembles tend
to a "drier" pattern this weekend, there's still enough low to mid
level moisture available for afternoon convection. With the
expected weather conditions, soils saturated, local effects, and
diurnal heating, the potential of flooding will remain limited to
elevated through this period, with showers during the morning
along windward sections and afternoon convection over interior and
western/southwestern Puerto Rico each day. Rainfall accumulations
will most likely promote ponding of water in roadways and poorly
drained areas, as well as urban and small stream flooding.

With the NE-E wind flow dominating the period, 925 mb temperatures
should remain near below normals.

&&

.AVIATION...

(06Z TAFs)

Expect -RA/VCTS posbl at TJSJ/TISX/TIST through 13z. Areas of SHRA
and SCT TSRA this aftn could produce tempo
MVFR/IFR conds and mtn obsc, particularly ovr TJBQ/TJSJ aft 28/17z.
VCTS/SHRA at TJPS for the most part. Despite this pattern, expect
mostly VFR conditions across all terminals through the forecast
period. E winds reaching speeds of up to 8-12 knots, accompanied by
higher gusts and sea breeze variations aft 28/13z.

&&

.MARINE...

Light to moderate east to southeast winds will prevail today and
tomorrow, turning from the northeast by Tuesday night. A deep layer
trough will continue to promote an unstable weather pattern across
the local waters. Showers and thunderstorms are expected to persist,
producing localized hazardous marine conditions, small craft should
exercise caution.

&&

.BEACH FORECAST...

Latest buoy observations show wave periods between 13 - 14
seconds, suggesting that pulses of the northeasterly swell
continue spreading across the local waters. Therefore, the high
risk of rip currents was extended through this afternoon for the
beaches of northern Puerto Rico, from Aguadilla to Fajardo, and
Culebra. As the swell dissipates across the local waters tonight,
a moderate risk of rip currents will prevail for the next few days
for the beaches in northern Puerto Rico, Culebra, and possibly
St. Thomas and St. John in the U.S. Virgin Islands.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST Tue Apr 29 2025

.SYNOPSIS...

The unsettled weather pattern will continue through Thursday due
to a series of troughs and abundant moisture. With saturated
soils and elevated river and stream flows, persistent moderate or
heavy rain will elevate flooding risk, including minor flooding,
flash flooding, river flooding, and landslides in steep terrain.
An improvement of the weather conditions is expected this weekend.

&&

.SHORT TERM...Today through Thursday...

Variably cloudy skies prevailed during the night and early morning
hours as showers drifted over land areas from coastal waters of PR
and the USVI. The Doppler radar estimated between a quarter to half
an inch of rain with the heaviest showers along portions of northern
and eastern PR, as well in the northern USVI. Minimum temperatures
were from the mid to upper 60s across the higher elevations of PR to
the mid-70s across coastal areas. The wind was light and variable.

A wet weather pattern will continue through the short-term period as
abundant moisture remains over the region under the influence of
deep layered trough over the western Atlantic that extends into the
northeastern Caribbean. Furthermore, a mid-to upper level cut-off
low is expected to develop northeast of the region by late Wednesday
and linger through Thursday. This will further enhance instability
aloft and trigger stronger thunderstorms with heavy rainfall each
afternoon over PR. For the USVI, this period will also be wettest
one. At the surface, weak steering winds will continue today and the
sea breeze influences will cause showers to drift mainly along the
mountain ranges of PR once again. Urban and small stream flooding,
as well as localized flash flooding, river flooding, and mudslides
in areas of steep terrain are expected.

Winds will acquire a northeasterly component and gradually increase
from tonight onwards as a high pressure builds over the western
Atlantic. This will also push a front or remnants of the frontal
boundary currently near 25N closer to the area by the end of the
forecast period, promoting further pooling of low-level moisture.
Taking into consideration the expected wet pattern and the already
saturated soils, a Flash Flood Watch could be issued for the second
part of the short-term period as the potential for flash flooding
and mudslides continues to increase. Residents and visitors are
urged to stay tuned for the latest forecast updates.

&&

.LONG TERM...Friday through Tuesday...

Deeper convection activity will be reduced this weekend,
transitioning to a wetter and unstable pattern by the beginning of
the workweek. The induced low mentioned in the last discussion is
still expected to develop in the Central Atlantic, along with a
surface high pressure in the Western Atlantic. Based on the latest
model guidance, the surface high should strengthen and migrate
eastward, pushing the low pressure more to the south, promoting
winds with a southerly component. A transition to a "drier" pattern
is still expected by Saturday due to ridging aloft. However, low
to mid level moisture content will remain high. In terms of
instability, upper- level dynamics with 250 mb wind speeds around
70 knots are still expected, which could bring ventilation aloft.
Although temperatures in the 500 mb layer should increase to
seasonal values, instability will be present. Taking that into
consideration, the conditions will be favorable for deep
convection activity. Overall, light to moderate showers will move
occasionally along windward sections each day. The combination of
above-normal moisture, light 0 - 3 km winds, local effects, and
diurnal heating will enhance afternoon convection each day of the
forecast, mainly over the interior and northern/northwestern
portions of Puerto Rico. Due to saturated soils and elevated river
and stream flows, the potential of flooding will increase,
isolated urban and small stream flooding are likely. Model
guidance is projecting a wetter scenario for Tuesday, with another
mid to high-level trough approaching the Caribbean. At the
moment, there's a medium chance of looking above climatological
normal moisture content, elevating the potential of flooding to
elevated.

If winds with the southerly component prevail, temperatures may
increase to near above climatological normals. However, the risk
of heat should remain low for the rest of the period.

&&

.AVIATION...

(06Z TAFs)

Mainly VFR conditions and VCSH in general expected across all
terminals through the period. However, SHRA/TSRA is expected to
develop over the interior of PR btw 29/16-22z, causing mostly VCTS
across all PR terminals and tempo MVFR conds at TJPS. Weak sea
breezes will dominate btw 29/13-20z, with a NE component becoming
the dominant wind direction aft 29/22z.


&&

.MARINE...

Light to moderate easterly winds will continue today, turning from
the northeast tonight. A deep layer trough will continue to promote
an unstable weather pattern across the local waters. Showers and
thunderstorms are expected to persist, producing localized hazardous
marine conditions, small craft should exercise caution.

&&

.BEACH FORECAST...

Latest buoy observations show pulses of a fading long-period
northeasterly swell, but wave heights remain between 2 - 3 feet.
No significant marine events are expected for the next few days.
Therefore, the risk of rip current will remain moderate for the
beaches in northern Puerto Rico, Culebra, and possibly St. Thomas
and St. John in the U.S. Virgin Islands by the end of the
workweek.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
501 AM AST Wed Apr 30 2025

.SYNOPSIS...

The wet and unstable weather pattern will continue through at least
Thursday evening due to a series of troughs and abundant moisture.
Soil saturation and soaring rivers will promote an elevated to
significant flooding threat, including minor flooding, flash
flooding, river flooding, and landslides in steep terrain. Although
an improvement of weather conditions is anticipated by this
weekend, abundant moisture will trigger showers and thunderstorms
in the afternoon.

&&

.SHORT TERM...Today through Friday...

Showers will continue to increase this morning across the U.S.
Virgin Islands and eastern Puerto Rico through the rest of the
morning hours. Ponding of water on roads and in poor drainage areas
is expected with this shower activity. Some showers could grow into
thunderstorms before noon across the mountain ranges of PR and last
through the evening hours. Due to already saturated soils and above
normal streamflows from previous days heavy rainfall, quick river
rises, mudslides, and flash flooding is likely with these
thunderstorms.

The wet weather pattern will continue through the rest of the short-
term period as abundant moisture content(PWAT above 2.00 inches)
lingers over the region. Later today, a cut off low is expected to
develop just northeast of the Leeward Islands from a mid-to upper
level trough over the central Atlantic. Global guidance suggest that
another but weak low reflected at the mid-levels will develop near
Cuba and Hispaniola on Thursday. These features will further enhance
instability across the northeastern Caribbean with colder than
normal 500 mb temperatures around -9C, and as they slowly drift
eastward a 75-80 kt jet segment will meander over the islands
through Friday. Therefore, thunderstorms over the next few days
could produce frequent lightning, small hail, and strong gusty winds
as well as further supporting long lasting rainfall activity over
the islands. Residents and visitors are urge to monitor the weather
conditions and remain vigilant to take necessary action to protect
life and property from the expected flooding impacts.

For more information please refer to the latest updates from the
Hydrologic Outlook(ESFSJU).

https://forecast.weather.gov/wwamap/wwa ... wa=SJU&wwa
=hydrologic%20outlook

&&

.LONG TERM...Saturday through Wednesday...

The long-term forecast suffered some changes. Winds on Saturday
will remain from the northeast, and will shift from the southeast
due to a surface high pressure building in the Western Atlantic
and the induced low in the Central Atlantic moving southward. The
latest model ensemble members are shifting to a wetter scenario
this weekend, with PWAT values above climatological normal (1.8 -
2.0 inches). The 500 mb temperatures should remain colder (-7 to
-8 Celsius), and the latest model guidance keeps suggesting that
the upper dynamics will remain stronger with winds in the 250 mb
layer around 70 knots, providing ventilation aloft. Additionally,
the Galvez-Davison Index (GDI) also displays the potential of
isolated thunderstorms mainly in the afternoons. Although model
guidance keeps suggesting drier air filtering in the upper levels
due to ridging, above-normal low to mid-level moisture content in
the region will trigger shower and thunderstorm activity in the
afternoons along interior Puerto Rico, moving into northern/western
Puerto Rico in the early evenings. Due to the heavy rainfall,
saturated soils, and soaring rivers, the risk of flooding will
remain limited, with mostly ponding of water in roadways, urban,
and poorly drained areas, along urban and small stream flooding.

Another mid to upper-level trough should move north of the
Caribbean, and induce a surface low. The interaction of this low and
a surface high pressure in the Central Atlantic could promote
southerly winds throughout the period. With this pattern, winds
may pool well above-normal moisture content into the region by
late Tuesday, with PWAT values around 2.0 - 2.2 inches for the
rest of the forecast period. The best moisture content might stay
in the east side of the CWA, impacting eastern sections of Puerto
Rico, Vieques, Culebra, and the U.S. Virgin Islands. However,
deeper afternoon convection should develop over interior Puerto
Rico, elevating once again the flooding potential.

With the southerly component in the winds and abundant moisture,
is likely to observe near above-normal temperatures during this
period. However, the heat risk will remain low for the rest of the
forecast period.

&&

.AVIATION...

(06Z TAFs)

Mainly VFR early in the fcst period. However, SHRA increasing from
the Atlantic and eastern waters of the islands will move at times
across the USVI/Eastern PR terminals thru the morning hours. This
can lead to brief MVFR cigs. SHRA/TSRA will develop btw 30/15z-23z
over the mountains and drift mainly southward under 8-14 kt ENE
winds. Therefore, expect mtn tops obscd across PR and tempo MVFR to
IFR conds mainly at TJPS. Elsewhere, -RA/VCTS expected thru the
evening hours.

&&

.MARINE...

A surface high pressure building in the Western Atlantic and a
deep layered trough will promote light to moderate east- northeast
to northeast winds for the next few days. Showers and thunderstorms
are expected to develop across the local waters, producing locally
higher winds and seas. Small craft should exercise caution and stay
weather alert.

&&

.BEACH FORECAST...

No significant swell events is anticipated for the next few days.
However, the moderate risk of rip currents will continue for the
beaches in northern Puerto Rico, and possibly for Culebra and the
northern USVI by tomorrow into the weekend.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
504 AM AST Thu May 1 2025

.SYNOPSIS...

Unsettled weather is expected over the next several days due to a
combination of abundant tropical moisture and a series of upper-
level troughs. The Flood Watch remains in effect for Puerto Rico
until Friday morning. The coverage and intensity of these showers
are expected to decrease somewhat during the upcoming weekend. Wet
and unsettled weather conditions may return next week (around
Wednesday).

&&

.SHORT TERM...Today through Saturday...

A Flash Flood Watch remains in effect for Puerto Rico until at least
Friday morning. Showers and thunderstorms will develop once again
over the same areas in the afternoon hours and could linger into the
evening hours. Saturated soils and above normal streamflows from
previous days excessive rainfall continues across portions of the
Cordillera Central and eastern PR. Any additional heavy rainfall
across these areas will pose an elevated to significant threat for
flash floods and landslides.

A deep layered low over the central Atlantic and a ridge east of the
Windward Islands will continue to promote moisture pooling across
the northeastern Caribbean throughout the reminder of the forecast
period. In addition, shower and thunderstorm activity will continue
across the islands on Friday and Saturday, mainly in diurnal
activity enhanced by another mid-to upper-level trough moving from
the northwest. Due to the unstable conditions aloft and abundant
tropical moisture over the area the risk for excessive rainfall will
remain elevated each day, particularly over central PR. Across the
USVI, moisture content will peak between the afternoon/evening hours
today and on Saturday. However, thunderstorms were developing just
west and south of St. Croix earlier this morning, and mostly light
to moderate rainfall was observed over land areas.

Residents and visitors are urge to monitor the weather conditions
and remain vigilant to take necessary action to protect life and
property from the expected flooding impacts. For more information
please refer to the latest updates from the Flash Flood Watch
(FFASJU).

https://forecast.weather.gov/wwamap/wwa ... &wwa=flood%2
0watch

&&

.LONG TERM...Sunday through Thursday...

The forecast for the beginning of the week remains on track. Winds
should remain from the southeast, due to the high surface pressure
building in the Western Atlantic and the deep layered trough
northeast of the CWA. Based on the latest model guidance, PWAT
values will remain above normal (1.8 - 2.0 inches) due to high
low to mid-level moisture content. The ridging in the mid to high
levels is still expected, filtering drier air. However, the 500 mb
temperatures should continue between -7 and -8 Celsius, colder
based on climatology. Additionally, strong upper-level winds could
bring ventilation aloft and consequently increase instability.
The combination of available moisture, local effects, slowing
winds, and daytime heating will bring light to moderate showers
and isolated thunderstorms during the afternoon, mainly over
interior Puerto Rico. A transition to a more unsettled and wet
pattern by the second part of the week is still expected, with
another deep mid to upper level trough approaching the local area
by Tuesday into Wednesday. The latest model guidance solution show
a drier air mass filtering into the region. However, the
available moisture remains above climatological normals. Global
models strongly suggest well above normal moisture content pooling
into the region beginning on Wednesday. Additionally, extreme
forecast indexes (EFI) continue highlighting the significant
weather closer to the region during that period. There's
confidence that the above normal moisture and mid to upper- level
dynamics should be enough to enhance deep afternoon convection
for the second part of the next workweek.

Due to saturated soils, above normal streamflows, and the
expected weather, the flood threat will remain elevated each day,
mainly for the interior of Puerto Rico.

The tendency of observing near above-normal temperatures in the
daytime continues, but the heat risk will remain low for the long
term forecast.

&&

.AVIATION...

(06Z TAFs)

SHRA/TSRA over the Caribbean waters may cause tempo MVFR conds
across the USVI terminals during the early morning hours. The sea
breeze convergence will cause +SHRA/TSRA development around noon
over the central portions of the islands, and MVFR to brief IFR
conds are possible once again along the southern terminals of the
islands. Mtn tops obscd and BKN/OVC lyrs btw FL040-200 expected.
Winds will remain ENE up to 13 kt with sea breeze variations along
the western and southern coastal areas, and stronger gusts near
TSTMs.

&&

.MARINE...

A surface high pressure building in the Western Atlantic and a
deep layered trough northeast of the region will continue
promoting light to moderate east- northeast to northeast winds for
the next few days. Showers and thunderstorms are expected to
develop across the local waters, producing locally higher winds
and seas. Small craft should exercise caution and stay weather
alert.

&&

.BEACH FORECAST...

The moderate risk of rip currents will continue for the beaches in
northern Puerto Rico, Culebra, and now for St. Thomas and St. John
in the U.S. Virgin Islands. Beachgoers must exercise caution due
to possible life- threatening rip currents along the surf zone and
stay weather alert.

The rip current risk will be low for the local islands by the end
of the weekend.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
501 AM AST Fri May 2 2025

.SYNOPSIS...

Once again, unsettled weather is expected over the next several
days due to a combination of abundant tropical moisture and a
series of upper- level troughs. The Flood Watch was extended
until Saturday morning due to the expected weather today.
Conditions will slightly improve on Sunday, but the wet and
unsettled weather conditions are likely return the next workweek.

&&

.SHORT TERM...Today through Sunday...

...A Flash Flood Watch remains in effect for Puerto Rico through
at least Saturday...

Shower and thunderstorm activity will continue to increase across
the U.S. Virgin Islands and the eastern sections Puerto Rico through
the rest of the morning hours. Ponding of water on roads and in poor
drainage areas is expected with this activity. Then, just before
noon and similar to previous days, thunderstorms are expected to
develop along portions of the Cordillera Central and last through
the evening hours. Due to already saturated soils and above normal
streamflows from previous days excessive rainfall and runoff, quick
river rises, landslides, and flash flooding is likely with these
thunderstorms once again. Winds will remain from the ENE but with a
prevailing easterly component in the steering flow, therefore,
portions of western PR that have not received as much rainfall in
the past days will see an increase in accumulations today.

The wet weather pattern will continue through at least Saturday,
with precipitable water content peaking around 2.15 inches from this
afternoon through Saturday, and decreasing to near 1.80 inches by
Sunday evening. This higher than normal moisture content will
combine with favorable atmospheric condtions at the mid-and upper-
levels from a developing trough/low to our northwest and produce
isolated to scattered thunderstorms with periods of heavy rainfall
for the next 24-36 hours. Residents and visitors are urge to monitor
the weather conditions and remain vigilant to take necessary action
to protect life and property from the expected flooding impacts
through the weekend. On Sunday, although the overall moisture
content is expected to decrease, diurnally induced afternoon
thunderstorms will develop once again over the mountain ranges of
PR, producing periods of locally heavy rainfall and triggering once
again flood concerns over extremely saturated soils.

For more information please refer to the latest updates from the
Flash Flood Watch (FFASJU).

https://forecast.weather.gov/wwamap/wwa ... &wwa=flood%2
0watch

&&

.LONG TERM...Monday through Friday...

No significant changes were made to the long-term forecast. The
synoptic pattern continues as expected, with a surface high pressure
building in the Western Atlantic that should move eastward and an
induced low lingering over the Central Atlantic. The mid to
upper- level trough highlighted by the global models for the past
few days is still expected to approach the CWA by Wednesday,
increasing instability aloft. The wind pattern will be variable,
as ENE winds will reduce by Tuesday and remain light for the rest
of the forecast period. Regarding the shower activity, the latest
global model ensembles showed an increase in uncertainty, with
some members going for a less aggressive solution compared to the
past few days. However, they still expect PWAT values to remain
near to above climatological normals (1.7 - 1.9 inches) throughout
the entire period. The temperatures in the 500 mb should increase
to seasonal values (around -7 Celsius) by Monday and Tuesday, but
will get colder by midweek (around -8 Celsius). Additionally,
stronger upper level winds should bring ventilation aloft,
increasing instability. Therefore, there's confidence of
development of thunderstorms during the afternoons each day.

Windward sections can expect light to moderate showers
moving occasionally during the night and the morning hours, while
the deep afternoon convection will concentrate on the interior
portions of Puerto Rico. With the recent heavy rainfall, above-
normal streamflows, saturated soils, and the expected conditions,
the flood threat remains elevated mainly over the aforementioned
areas. There should be an improvement in the weather conditions by
Friday, as a drier air mass filters into the region, promoting
stable conditions across the local islands.

Seasonal temperatures should prevail for the rest of the forecast
period, with the heat risk remaining low across the CWA.

&&

.AVIATION...

(06Z TAFs)

SHRA and iso TSTMs increasing from the Atlantic and eastern waters
of the islands could move across the USVI/Eastern PR terminals thru
the rest of the morning hours. This can lead to brief MVFR cigs. Mtn
tops obscd and BKN/OVC lyrs btw FL030-250 expected aft 02/16z, when
SHRA/TSRA develops till at least 02/23z over the mountains and
western PR. Steering winds will have a more easterly component
today, but in general ENE winds expected at the sfc and increasing
btw 12-16 kt with stronger gusts aft 02/14. Stronger sustained winds
btw 16-21 kt are expected fm 02/22z-03/06z across the Atlantic and
eastern waters btw PR and the USVI.

&&

.MARINE...

A surface high pressure building across the western Atlantic and a
deep layered trough northeast of the region will continue promoting
light to moderate east-northeast to northeast winds for the next few
days. Showers and thunderstorms are expected to develop across the
local waters, producing locally higher winds and seas. Small craft
should exercise caution and stay weather alert.

&&

.BEACH FORECAST...

The moderate risk of rip currents will continue for the beaches in
northern Puerto Rico, Culebra, and St. Thomas and St. John in the
U.S. Virgin Islands. Beachgoers must exercise caution due to
possible life- threatening rip currents along the surf zone and
stay weather alert.

The rip current risk is still expected to gradually decrease this
weekend into early next week.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
457 AM AST Sat May 3 2025

.SYNOPSIS...

Unstable and wet weather conditions are anticipated to continue
through next week due to a combination of abundant tropical
moisture and a series of upper-level troughs moving over the
region. The Flood Watch was extended through this evening due to
continuous rainfall activity resulting in hazardous weather
conditions across Puerto Rico today. Unsettled weather conditions
are likely to persist through mid-week.

&&

.SHORT TERM...Today through Monday...

...A Flash Flood Watch remains in effect for Puerto Rico through
this evening...

Mostly cloudy skies prevailed overnight as strong thunderstorms
developed along the north-central to eastern sections of Puerto Rico
and across the Atlantic waters. Additional showers were increasing
in the past few hours across the Caribbean waters and the eastern
interior portions of Puerto Rico. A rain gauge in Vega Baja reported
over 6 inches of rain in less than 4 hours. River flooding was
observed in Rio Grande, Naguabo, and Luquillo, and minor river
flooding along Rio Guanajibo due to yesterday's rainfall.

The current wet weather pattern is expected to continue until late
tonight. Precipitable water values will remain above normal levels,
between 2.15 and 2.20 inches today, before gradually decreasing to
around 1.80 inches by Sunday evening. This above-normal moisture,
combined with favorable mid- to upper-level conditions from low
pressure to our north, will continue to produce isolated to
scattered thunderstorms with periods of heavy rainfall through at
least tonight. Therefore, the Flash Flood Watch was extended through
at least 8 PM AST tonight. The potential for landslides will
continue along steep terrain due to saturated soils.

Although the overall moisture content is anticipated to decrease on
Sunday and Monday, afternoon thunderstorms triggered by daytime
heating will likely develop again, mainly along portions of the
Cordillera Central and downwind from the el Yunque area. These
storms may bring localized heavy rainfall and heighten flood
concerns due to extremely saturated soils. Residents and visitors
are strongly encouraged to monitor weather conditions and be
prepared to take protective measures against potential flooding
impacts for the rest of the weekend, as waterfalls, creeks, and
small streams will react quickly to any brief period of heavy
rainfall upstream.

For the additional information and updates, please refer to: the
Flash Flood Watch (FFASJU), Hazardous Weather Outlook (HWOSJU),
Graphical Hazardous Weather Outlook
(https://www.weather.gov/erh/ghwo?wfo=sju)

.LONG TERM...Tuesday through Saturday...

A deep layerd low pressure north of the area and a series of
surface induced troughs will promote a east to northeast wind flow
for the first half of the period. Then, winds are expected to
become from the southeast by the end of the workweek as the low
pressure shifts towards the west. Abundant low-level moisture will
predominate over the long term- period with precipitable water
values between 1.60 to 1.75 inches. During this period the 500 mb
temperatures will drop into the -7 to -9 degrees Celsius,
suggesting the potential to support convective activity across the
region. Throughout the week, instability will persist as the low
pressure and the induced surface trough pattern prevail in the
region. Therefore, there is an increased potential to observe
afternoon convective activity along portions of the interior and
western Puerto Rico each day. With the rainfall events from
previous days, above- normal streamflows and saturated soils, the
flood threat remains elevated. The latest model guidances are
suggesting a change in the weather pattern by the end of the week
into the weekend with the entrance of drier air into the area.
Seasonal temperatures are anticipated to prevail for the rest of
the forecast period, with the heat risk remaining low.

&&

.AVIATION...

SHRA/TSRA will continue across the local area today. Tempo MVFR to
brief IFR conds are possible across all terminals today, during the
day particularly across PR, and in the late afternoon/evening hours
in and around the USVI terminals. Mtn tops obscd expected to
continue thru 04/00z. East winds 10-15 kt with stronger gusts and
sea breeze variations aft 03/13z.

&&

.MARINE...

A surface high pressure building across the western Atlantic and a
deep layered trough northeast of the region will promote light to
moderate east to northeast winds for the next few days. Showers and
thunderstorms are expected to develop across the local waters,
producing locally higher winds and seas. Small craft should exercise
caution and stay weather alert.

&&

.BEACH FORECAST...

There is a moderate risk of rip currents for the exposed beaches
of northern Puerto Rico, Culebra, and the U.S. Virgin Islands.
Beachgoers must exercise caution due to possible life- threatening
rip currents along the surf zone and stay weather alert. The rip
current risk is still expected to gradually decrease by early next
week.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
510 AM AST Sun May 4 2025

.SYNOPSIS...

A Significant Flooding Threat continues across Puerto Rico due to
the excessive rainfall activity expected for today in combination
with the observed activity over the past week. The Flash Flood
Watch has been extended through this evening. Strong thunderstorms
and additional heavy rainfall are expected, especially during the
afternoon, resulting in hazardous conditions for flash flooding,
landslides, quick river rises, and water surges. Residents and
emergency management partners are urged to remain vigilant,
especially in flood-prone and steep terrain areas.

&&

.SHORT TERM...Today through Tuesday...

...A Flash Flood Watch remains in effect for Puerto Rico through
this evening...

Late Saturday night, a line of heavy rain impacted the northern
coastline of PR, but it dissipated by midnight. On the other hand, a
line of thunderstorms moved over St Croix after midnight, producing
between 1 and 2 inches of rain over portions of the vicinity of the
islands. Additionally, river sensors along the Rio Guanajibo, Rio
La Plata, and Rio Grande de Manati surpassed the flooding stage
overnight. However, at the moment of this discussion, rivers have
returned below the flood stage. Winds are mainly from the east to
east-southeast at less than 10 MPH, but locally higher near
thunderstorms. Minimum temperatures along the interior higher
portions of Puerto Rico are in the low 60s, while along the US
Virgin Islands are in the low 70s in Cotton Valley, St Croix.

A Significant flooding threat persists across Puerto Rico due to the
excessive rainfall activity observed over the past week. Radar
Estimated Rainfall Accumulations have surpassed 15 inches in some
areas, especially along the interior and mountain sections, where
soils are saturated and river levels are running high. Due to these
preexisting hazardous conditions, the Flash Flood Watch has been
extended through this evening, as we expect another round with
widespread rain activity, especially along and to the north of
Cordillera Central and La Sierra de Luquillo. The primary weather
threats include urban and small stream flooding, river flooding,
flash flooding, mudslides, and landslides, particularly in
mountainous, steep terrains. Additionally, strong thunderstorms
capable of producing strong winds, frequent lightning, and even hail
are expected, especially during the afternoon. Residents and
emergency management partners are urged to remain vigilant,
especially in flood-prone and steep terrain areas. Continue to
monitor official updates and be prepared to take immediate action
should Flash Flood or Flood Warnings be issued.

The typical May convective pattern will prevail on Monday and
Tuesday. Due to the vulnerable preexisting environmental conditions,
we might continue to see flooding and landslides over areas where
the afternoon convection develops. Also, an east-northeast wind flow
expected to return around Monday and Tuesday, combined with the land
breeze, will promote low-level convergence along the northern
sections of PR and near the US Virgin Islands, where we might see
periods of moderate to locally heavy rain in the evenings, too.


.LONG TERM...Wednesday through Sunday...

A low pressure system north of the area will promote east to
northeasterly winds trough the first half of the long term period.
However, winds are expected to shift from the southeast as the
low pressure migrates westwards over the Atlantic. The latest
model guidances have been consistent with previous model runs on
the entrance of a relatively drier airmass into the region,
promoting stable conditions over the islands. The precipitable
water content (PWAT) will remain within normal climatological
values of 1.6 to 1.8 inches through much of the forecast period.
Nonetheless, at the 500 mb level the temperatures will drop into
-9 to -10 degrees Celsius suggesting the potential to support
convective activity during the afternoon hours over the islands.

Under the aforementioned pattern, typical seasonal weather
conditions are anticipated with sunny to partly cloudy mornings
across Puerto Rico and the U.S. Virgin Islands. Then, followed by
afternoon convective activity over portions of central and western
Puerto Rico each afternoon. With the rainfall activity from previous
days/weeks, it is important to remember to stay weather alert due to
above-normal streamflows and saturated soils that may result in
localized flooding across portions of Puerto Rico. The 925 mb
temperatures will remain at normal or below-normal values during the
week. Highs are anticipated in the low to mid 80s across the
coastal and urban areas, and in the mid to upper 70s.

&&

.AVIATION...
(06Z TAFs)

SHRA/TSRA continues to affect the local flying area, this will
lead to periods of MVFR or IFR conds. Afternoon convection will
develop from 4/15 to 4/22z. Periods with SHRA/TSRA will impact the
eastern sections of PR and the USVI, where MVFR or even IFR conds
can be expected if the activity affects the local terminal. Winds
will generally be calm to light and vrb thru at least 4/13z, when
they will return from the E-ESE at around 10 kt, with sea
breezes, becoming calm to light and variable aft 4/23z once again.


&&

.MARINE...

A surface high pressure building across the western Atlantic and a
deep layered trough northeast of the region will promote light to
moderate east to northeast winds for the next few days. Showers and
thunderstorms will continue to develop across the local waters today,
producing locally higher winds and seas.

&&

.BEACH FORECAST...

There is a moderate risk of rip currents for the beaches of Puerto
Rico from Aguadilla to Fajardo. Beachgoers must exercise caution
due to possible life- threatening rip currents along the surf zone
and stay weather alert. The rip current risk is still expected to
gradually decrease by early this week.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
416 AM AST Mon May 5 2025

.SYNOPSIS...

A drier air mass filtering over the region will maintain calm and
stable weather conditions through the morning hours. Later today,
afternoon convective will return, enhanced by topographic effects,
sea breezes, and diurnal heating, resulting in periods of
moderate to locally heavy rain due to thunderstorms. A short wave
trough will reach the islands on Tuesday, increasing instability
and the potential to observe heavy rainfall once again. There is
a limited to elevated risk of flooding rains across the island
each day.

&&

.SHORT TERM...Today through Wednesday...

A drier air mass filtering over the islands mainly resulted in clear
skies across Puerto Rico and the US Virgin Islands. GOES-19 infrared
channel and the Doppler radar observed some clouds and showers,
respectively, mainly across the Caribbean waters overnight. Once
again, low temperatures dug into the low 60s along mountains and
valleys as the clear skies enhanced nighttime cooling. Winds were
calm to light and variable, influenced by land breeze.

This morning, we expect calm conditions, allowing the temperature to
reach the upper 80s or even the low 90s, especially along urban
areas or coastal locations. These air temperatures, combined with
the available moisture, will promote the return of warm heat
indices, especially during the maximum heating time near noon.
However, the seasonal afternoon convection will return, enhanced by
local mountains, sea breezes, and diurnal heating, resulting in
periods of moderate to locally heavy rain due to thunderstorms. The
highest rainfall amounts are expected across the interior sections
and downwind from the Luquillo Mountain Range, giving place to the
San Juan Streamer. Model guidance generally suggests between 1 and 2
inches of rain with locally higher amounts, especially along PR's
interior portions. Since mid-April, PR received between 10 and 20
inches of rain along the interior sections, saturating the soils and
producing above-normal river levels. Thus, PR has an elevated threat
of flooding, as many locations in the interior and near mountains
are vulnerable. Showers will move inland over the US Virgin Islands
from mid-morning onward as additional moisture will be lifted from
the Caribbean, especially across St Croix.

A short wave trough aloft will swing by the islands on Tuesday, and
a vertical transect shows deeper moisture pooling over the islands
by the peak of the diurnal heating, which could assist in the
formation of showers one more time by Tuesday afternoon. Also, as
winds return from the northeast during the evening, they will
increase the interaction with the land breeze, promoting late
evening activity along the Atlantic coastline of PR. The afternoon
and evening activities will create a limited to elevated risk of
flooding rains across the islands. As the mid to upper-level trough
amplifies over the Northeast Caribbean, instability will increase
the potential to observe deep convection. The limiting factor we see
in the model guidance is the moisture erosion they suggested.
However, we will continue to monitor the evolution of the weather
conditions as we expect the afternoon and evening convection to
develop each day.

.LONG TERM...Thursday through Monday...

A strong surface high pressure located over the central toward the
northeastern Atlantic will promote east to southeasterly winds
throughout the forecast period. Winds will become from the east on
Sunday, as another surface high builds over the western Atlantic and
moves toward the central Atlantic. A mid-level ridge is expected to
build over the region, promoting relatively drier conditions and
stability aloft. The latest precipitable water content has near
normal climatological values from 1.4 to 1.6 inches. Under this
pattern, limited rainfall activity is expected over the area.
However, afternoon showers are possible over portions of the
interior, western and northern Puerto Rico with isolated
thunderstorms due to the combination of daytime heating and
topographic effect. By the end next weekend, a wind surge could
potentially reached the area, increasing once again the likelihood
to observe showers showers and isolated thunderstorms over the
island. The 925 mb temperatures will remain at normal
climatological values for this time of the year, with temperatures
in the mid 80s along the coastal and urban areas; and from the
mid to upper 70s in the mountains. Across the U.S. Virgin Islands,
mainly fair weather conditions will prevail with limited or none
precipitation.

&&

.AVIATION...
(06Z TAFs)

VFR conditions will persist this morning. However, SHRA/TSRA will
develop near ISX around noon and across the interior sections of PR,
impacting JSJ/JBQ and the VCTY of JPS. This activity will mainly
form between 5/15-22z, when MVFR conditions are likely, if it moves
over those terminals. The winds will be calm to light and VRB thru
5/13z, then increasing at 9-13 kt from the E-ESE with sea breeze
variations.

&&

.MARINE...

A broad surface high pressure extending from the western into the
Central Atlantic, in combination with an induced surface trough just
northeast of the region, will result in light to moderate easterly
winds across the local waters. Mariners can expect seas between 3 to
5 feet for the next several days. Thunderstorms are likely today
across the regional waters, resulting in higher seas with the
strongest activity.

&&

.BEACH FORECAST...

There is a moderate risk of rip currents for the beaches of Puerto
Rico from Aguadilla to Fajardo. Beachgoers must exercise caution
due to possible life- threatening rip currents along the surf zone
and stay weather alert. The rip current risk is still expected to
gradually decrease by Tuesday through the rest of the week.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
459 AM AST Tue May 6 2025

.KEY MESSAGES...

* Afternoon showers and thunderstorms will continue to pose an
elevated threat of flooding, especially today and Wednesday.

* Due to ongoing soil saturation, the risk of mudslides/landslides
persists along the steep terrains.

* Conditions will gradually improve after midweek as a somewhat
drier air mass and more stable conditions build over the
islands.

* The risk of rip currents will become moderate by Sunday and
Monday as the easterly winds increase across the islands.

&&

.SHORT TERM...Today through Thursday...

Mostly calm weather conditions prevailed overnight across Puerto
Rico and the U.S. Virgin Islands. Doppler radar and satellite
observations showed the development of passing showers, mainly over
the local Caribbean waters. Winds were light and variable throughout
much of the night. Minimum temperatures were seen in the mid to
upper 60s in the mountains, and from the low to mid 70s along the
coastal and urban areas.

Today, fair weather conditions are expected to prevail during the
morning hours with few passing showers reaching the windward
portions of the islands. However, the proximity of a short wave
trough aloft and abundant moisture over the region will help to
enhance afternoon convective activity over Puerto Rico today through
Wednesday. The latest precipitable water content guidance (PWAT) has
values of 1.8 to 2.0 inches. In addition, at the 500 mb level the
temperatures will drop into -8 to -9 degrees Celsius, increasing the
potential to support deep convection. Under this moist environment
in combination with daytime heating and local effects, heavy showers
with thunderstorms are likely over the interior and western Puerto
Rico. Therefore, there is a limited to elevated risk of flooding
rains, once again, over the islands. Weather conditions will likely
improve from Thursday onward with the entrance of a drier airmass
into the region with PWAT values at normal-to-below normal
climatological values (1.4 to 1.6 inches).

Seasonal temperatures will continue over the next several days.
Maximum temperatures are expected to remain in the mid 80s along the
coastal and urban areas, and from the upper 70s to low 80s across
the Central Mountain Range.

Due to the recent rain events over Puerto Rico, soils are very
saturated and any additional rainfall activity could lead to flash
flooding, mudslides and landslides, quick river rises, and water
surges along already impacted areas. Residents and visitors should
continue to monitor the weather conditions in your location as the
day progresses for safety concerns.

.LONG TERM...Friday through Tuesday...

When the upper-level trough exits the region by Friday, moving
eastward into the Atlantic Ocean, model guidance indicates dry air
intrusion above 700 MB over the Northeast Caribbean. This air
mass aloft will induce subsidence, limiting the potential for
widespread rain activity each day. However, at low levels,
sufficient tropical moisture interacting with the easterly winds
will continue to promote periods of showers across the windward
locations in the US Virgin Islands and Puerto Rico, mainly due to
low-level convergence, followed by afternoon convection over the
interior and western Puerto Rico due to sea breeze, local effects,
and diurnal heating each day.

Winds will increase by the end of the week as a surface high-
pressure building across the Central Atlantic tightens the local
pressure gradient. An advective pattern may increase the frequency
of the typical passing showers across the windward locations,
moving further inland across PR due to these rising winds.

Model guidance shows another deep trough approaching the
Northeast Caribbean by next Tuesday, potentially increasing the
instability over the region and the likelihood for thunderstorm
development with flooding rain.

&&

.AVIATION...
(06Z TAFs)

Mainly VFR conds will prevail across all TAF sites during the
forecast period. However, SHRA/TSRA development is likely over the
vicinity of TJPS, resulting in periods of brief MVFR conds aft 6/17-
22Z. Calm to light VRB winds will prevail thru 5/13z, then
increasing at 10-13 kt from the ENE with higher gusts and sea
breeze variations.

&&

.MARINE...

A broad surface high pressure extending into the Central Atlantic,
in combination with an induced surface trough northeast of the
region, will result in light to moderate easterly winds across the
local waters today, then becoming light to gentle through the end of
the workweek. Mariners can expect seas between 2 to 4 feet,
occasionally 5 feet, for the next several days. Occasional
thunderstorms are likely across the regional waters, especially in
the afternoon, resulting in dangerous conditions for mariners.

Choppy seas may return by the end of the week and early next week.

&&

.BEACH FORECAST...

Beachgoers can expect a low risk of rip currents across the local
beaches. However, remember that rip currents often occur near
groins, jetties, reefs, and piers. The risk of rip currents will
become moderate on Sunday and Monday next week.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
457 AM AST Wed May 7 2025

.KEY MESSAGES...

* Due to afternoon rain and thunderstorms, flooding will likely
return in the PR's interior and western areas.

* Since the soil is already saturated, there is a moderate to
high chance of mudslides and landslides in steep places in PR.

* Conditions should gradually improve from Thursday onward as
drier air and more stable weather build over the islands.

* The risk of rip currents will return to moderate or high levels
by next week as easterly winds strengthen across the Northeast
Caribbean.

&&

.SHORT TERM...Today through Friday...

Calm weather conditions prevailed overnight, under clear to partly
cloudy skies. Doppler radar analysis showed a small area of
convective activity southwest of Cabo Rojo producing frequent
lightning, however, this activity remained over the Caribbean
waters. Minimum temperatures were seen in the low to mid 60s along
the Central Mountain Range, and in the low to mid 70s along the
coastal and urban areas of the islands. Winds were light and
variable throughout the night.

Mainly fair weather conditions are anticipated this morning with few
passing showers moving over the windward portions of the islands
from time to time. However, as the day progresses conditions will
become unstable and favorable for afternoon convective activity,
particularly over central Puerto Rico.

The proximity of a deep-layer trough and sufficient moisture over
the region will favor the development of heavy rainfall activity and
thunderstorms today. The precipitable water values (PWAT) of 1.8 to
2.0 inches, cooler temperatures at the 500 mb level (-8 to -9
degrees Celsius), daytime heating and local effects will support and
enhance the expected activity. Therefore, the potential to observe
flash flooding, mudslides/landslides, quick river rises and water
surges remain high.

By Thursday into the weekend, weather conditions will begin to
improve. As the deep-layer trough migrates towards the east, drier
air will start to filter into the area. The latest model guidance
continues to suggest a drop of PWAT values to below-normal
climatological values (1.4 to 1.5 inches) and warmer temperatures at
the mid-levels. This pattern of drier and stable conditions aloft
will limit the rainfall activity over the area. Nonetheless, showers
are possible over portions of western Puerto Rico due to daytime
heating and local effects, mainly in the afternoon. Seasonal
temperatures will continue over the islands for next several days.
Maximum temperatures are expected to remain in the mid 80s along the
coastal and urban areas, and from the upper 70s to low 80s across
the Central Mountain Range.

Soils are very saturated across the region from the previous days
rainfall events. Therefore, any additional rainfall this afternoon
over central Puerto Rico could lead to flash flooding,
mudslides/landslides, quick river rises, and water surges along
already impacted areas. Residents and visitors should continue to
monitor the weather conditions today for safety concerns.

.LONG TERM...Saturday through Wednesday...

A mid-level high-pressure system will build over the islands on
Saturday, leading to dry air and subsidence aloft. This will limit
the potential for widespread rain each day. However, the
available low-level tropical moisture, combined with easterly
winds, will still result in periods of showers across the windward
areas in the US Virgin Islands and Puerto Rico. This activity
affecting the windward sections could be enhanced by low-level
convergence. The sea breeze, local effects, and daily heating will
drive the afternoon convection over the interior and western
Puerto Rico.

Winds will pick up over the weekend as a surface high-pressure
builds across the Central Atlantic, tightening the local pressure
gradient. This change in weather patterns will increase the
typical passing showers in the windward areas, which could extend
further inland across Puerto Rico and the US Virgin Islands due to
the increasing winds.

&&

.AVIATION...
(06Z TAFs)

Mainly VFR conds will prevail across all terminals during the next
24 hrs. However, periods of brief MVFR conds are likely at TJPS due
to SHRA/TSRA btw 07/17-23Z. Light and variable winds will prevail
thru 07/13z, increasing at 10-15 kt from the ENE aft 07/14Z. Higher
gusts are possible in and near TSRA.

&&

.MARINE...

A broad surface high pressure extending into the Central Atlantic,
in combination with an induced surface trough northeast of the
region, will result in light to gentle through the end of the
workweek. Winds will increase by the end of the weekend as the
surface high pressure builds across the Atlantic. Mariners can
expect seas between 2 to 4 feet, occasionally 5 feet, for the next
several days. Occasional thunderstorms are likely across the regional
waters, especially in the afternoon, resulting in dangerous
conditions for mariners.

&&

.BEACH FORECAST...

Beachgoers can expect a low risk of rip currents at local beaches
throughout the workweek. However, keep in mind that rip currents
often occur near groins, jetties, reefs, and piers. The risk of
rip currents will increase to moderate from Saturday onward.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
511 AM AST Thu May 8 2025

.KEY MESSAGES...

* Afternoon convection is expected every afternoon across the
interior and southwestern PR with showers and isolated
thunderstorms.

* The risk of flooding remains elevated for the same vulnerable
areas that have received rain during the past consecutive days.
Soils remain saturated, therefore landslides are possible.

* Strengthening winds by early next week will elevate the risk of
life-threatening rip currents for beachgoers and create rough
seas for small craft.

&&

.SHORT TERM...Today through Saturday...

Radar and satellite showed an area with showers and thunderstorms
extending from the Caribbean Offshore waters into the islands of St
Croix. Rain gauges across the island reported around half an inch of
rain across the northern portion, near Christiansted. The northern
USVI and PR observed quiet weather conditions with little or no
rain. Minimum temperatures dropped into the low 60s along the
mountains and valleys to the low 70s along the coastal locations.
Winds were calm to light and variable under land breeze influence.

An upper-level trough will linger near the region, leaving the
islands under unfavorable dynamics for organized widespread
convection. A drier air mass will also build aloft, while the
available low-level moisture will continue to pull over the islands.
Therefore, during the morning, we expect muggy apparent temperatures
in the mid or upper 90s, with a mixture of sunshine and clouds.
Then, local effects, diurnal heating, and sea breeze will promote
the formation of isolated thunderstorms, mainly across the mountain
areas, spreading to the southwest due to the northeasterly winds. As
a result, we left the elevated threat of flooding rains during the
afternoons. Additionally, under the east-northeast wind flow, a line
of showers may develop each evening along the northern coast of PR,
affecting those coastal municipalities.

A similar weather pattern is expected on Friday. While there won't
be a strong trade wind inversion and overall instability will be
low, afternoon showers and isolated thunderstorms may still occur
due to lingering moisture and daytime heating. These storms are
likely to be brief, but heavier downpours could cause localized
flooding, especially in areas with saturated soils.

On Saturday, the surface high pressure building across the Central
Atlantic will tighten the local pressure gradient, increasing local
winds and pooling additional tropical moisture across the islands.
Under this advective pattern, we expect the arrival of showers
across the windward locations, moving further inland due to the
increasing winds.


.LONG TERM...Sunday through Thursday...

The inherited forecast remains valid, with the latest model
guidance continuing to support near-normal precipitable water values
and 500 mb temperatures for this time of year. A mid-level high-
pressure system is expected to strengthen over the region during
the weekend, promoting dry air intrusion and subsidence aloft. As
a result, the potential for widespread rainfall will remain
limited throughout the long-term period.

Nonetheless, pockets of low-level tropical moisture, in combination with
prevailing easterly winds, will support periods of morning
showers across windward sections of Puerto Rico and the US Virgin
Islands. During the afternoon hours, local effects such as sea
breeze convergence, diurnal heating, and orographic influences
will contribute to the development of convective showers,
particularly across interior and western Puerto Rico.

From Monday through Wednesday, surface winds are expected to gradually
increase as a strong high-pressure system builds over the central
Atlantic. This will tighten the local pressure gradient and
enhance trade wind flow across the region.

&&

.AVIATION...
(06Z TAFs)

VFR conditions will prevail today. However, SHRA/TSRA will develop
near St Croix early this morning and could impact ISX. In the
afternoon, SHRA/TSRA will develop along the interior of PR and
downwind from USVI, briefly affecting local terminals between 0817
and 0823z. Another round may form during the evening, impacting JSJ.
Expect calm to light and variable winds through 8/13z, then
returning from the E/ENE at 10 to 15 kt, but locally higher due to
sea breeze and near TSRA.

&&

.MARINE...

A broad surface high pressure extending into the Central Atlantic,
in combination with an induced surface trough northeast of the
region, will result in light to gentle through the end of the
workweek. Winds will increase by the end of the weekend as the
surface high pressure builds across the Atlantic. Mariners can
expect seas between 2 to 4 feet, occasionally 5 feet, for the next
several days. Occasional thunderstorms are likely across the regional
waters, especially in the afternoon, resulting in dangerous
conditions for mariners.

&&

.BEACH FORECAST...

Beachgoers can expect a low risk of rip currents at local beaches
throughout the workweek. However, keep in mind that rip currents
often occur near groins, jetties, reefs, and piers. The risk of
rip currents will increase to moderate from Saturday onward.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
455 AM AST Fri May 9 2025

.KEY MESSAGES...

* Showers will continue to filter across eastern Puerto Rico and
the U.S. Virging Islands through the morning hours today.

* Like previous days, afternoon showers and isolated
thunderstorms are expected each day and could generate localized
flooding impacts, including landslides in areas of steep
terrain, particularly in vulnerable areas with saturated soils.

* Strengthening winds over the weekend into early next week will
elevate the risk of life-threatening rip currents for beachgoers
and create rough seas for small craft.

&&

.SHORT TERM...Today through Sunday...

A variable weather pattern prevailed during the night hours, where
shower activity was observed throughout northeastern Puerto Rici.
Most of the showers were observed first along Dorado and the
vicinity around Rio Grande and Loiza. Rainfall accumulations were
one to two inches in some areas. Overnight temperatures remained in
the lower 80s around the coastal areas and even more fresh across
the interior sections.

A stable and generally dry weather pattern will persist across
Puerto Rico and the U.S. Virgin Islands through at least today,
primarily due to the presence of a mid-to upper-level ridge
extending over the northeastern Caribbean. This ridge promotes
atmospheric subsidence, suppressing vertical motion and deep
convective development. Model guidance indicates that lapse rates in
the mid-levels, between 700 and 500 millibars, range from 5.0 to 5.5
degrees Celsius per kilometer,allowing a more stable pattern.
Additionally, temperatures at 500 millibars remain cool, near minus
7 degrees Celsius, but not cold enough to generate significant
widespread thunderstorms activity. Moisture content remains limited,
with PWAT values fluctuating between 1.70 and 1.75 inches, which
aligns closely with climatological normals. These conditions will
continue to support mostly stable weather, with only isolated to
scattered afternoon showers developing across interior and western
Puerto Rico due to local sea breeze convergence and orographic
effects. Thunderstorm activity is expected to remain limited because
of the weak instability and capping aloft. Across the U.S. Virgin
Islands, stable and dry conditions will dominate, with only a few
brief and shallow showers possible in the early morning hours.

By Saturday into Sunday, conditions turn more stable, as shown by
the 250 MB with the presence of a mid to upper-level ridge. This
feature will provide stable and drier conditions aloft and warmer
temperatures at 500 MB, rounding from -7 to -6 Celsius degrees.
Although upper-level conditions will significantly improve, PWAT
water values will rise slightly from 1.70 to 1.90 inches. The
available moisture will support more favorable conditions for
afternoon shower development. Although this increase in moisture may
lead to more frequent afternoon showers, particularly across the
northwestern and interior portions of Puerto Rico, the lack of
significant instability aloft will limit the intensity and vertical
growth of any convection. Rainfall accumulations are expected to be
light to moderate at most. The U.S. Virgin Islands may experience a
slight increase in early morning or overnight showers, but no major
rainfall or thunderstorm activity is anticipated. Overall,
conditions will trend toward slightly wetter afternoons while still
being influenced by stable upper-level conditions.


.LONG TERM...Monday through Friday...

The long-term period begins with a strengthening surface high over
the central Atlantic, which will tighten the local pressure
gradient and lead to increasing trade winds from Monday through at
least Wednesday. At the same time, precipitable water values are
expected to remain near seasonal normals (around 1.6 to 1.8
inches), supporting typical afternoon shower and thunderstorm
development across the interior and western sections of Puerto
Rico. Eastern Puerto Rico and the US Virgin Islands will likely
experience brief, trade wind-driven showers during the late night
and early morning hours.

During the second half of the workweek, a developing low-pressure system
over the western Atlantic will introduce changes to the overall
pattern. As it deepens and moves eastward, it will increase
moisture transport into the region while weakening the trade wind
inversion and enhancing upper-level support. PWAT values could
rise above 1.8 inches, allowing a more humid and unstable
environment. This evolving setup will favor more widespread and
intense convection Thursday and Friday, with showers becoming
deeper and more persistent. We encourage people to stay informed
with the latest updates.

&&

.AVIATION...
(06Z)

VCSH to SHRA will persist along TJSJ, TIST until 09/15Z.
Winds will continue VRB peaking up at 09/15Z from the E at 15
knots with gusty winds near the showers. SHRA/TSRA will start at
around 09/18Z across mountains, inducing lower ceilings and a
reduction in VIS. VCSH/SRHA will affect TJBQ at 09/18Z.

&&

.MARINE...

A broad surface high pressure extending into the Central Atlantic,
in combination with an induced surface trough northeast of the
region, will result in light to gentle flow through the end of the
workweek. Winds will increase by the end of the weekend as the
surface high pressure builds across the Atlantic. Mariners can expect
seas between 2 to 4 feet, occasionally 5 feet, for the next several
days. Occasional thunderstorms are likely across the regional waters,
especially in the afternoon, resulting in dangerous conditions for
mariners.

&&

.BEACH FORECAST...

Beachgoers can expect a moderate risk of rip currents along the
northwestern coastal areas of Puerto Rico, while the rest of the
local beaches should experience a low risk throughout the
workweek. However, life- threatening rip currents often occur near
groins, jetties, reefs, and piers.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
518 AM AST Sat May 10 2025

.KEY MESSAGES...

* Variable weather conditions with afternoon showers are forecast
from today into early next workweek.

* An unstable and wet pattern is forecast for the last part of the
long term.

* Warmer-than-normal conditions are likely over the weekend.

* There is a moderate risk of rip current across the northern
coastal areas of Puerto Rico and St. Croix.

&&

.SHORT TERM...Today through Monday...

Overnight, generally calm weather prevailed across the interior and
western portions of Puerto Rico. In contrast, the eastern half of
the island, along with Vieques, Culebra, and the U.S. Virgin
Islands, experienced persistent rainfall after 3 AM. The heaviest
precipitation accumulations ranged from 1 to 4 inches in
municipalities like Ceiba, Fajardo, Luquillo, and Rio Grande,
prompting the issuance of flood advisories in those municipalities.
Temperatures remained in the mid to upper 70s across coastal and
urban areas, while mountain regions observed cooler conditions, with
lows in the 60s to low 70s. Winds were light and generally from the
east-southeast.

Looking ahead to today and through the rest of the weekend, a
gradual shift toward a more humid and unstable weather pattern is
expected. Precipitable water values will range between 1.6 and 1.9
inches, indicating increased moisture availability. This increase in
moisture, along with the approach of a mid- to upper-level shortwave
trough, will enhance atmospheric instability, particularly from late
Saturday into Sunday.
At the surface, an intensifying high-pressure system over the
Atlantic will promote east-southeasterly winds across the region.
This flow will support warmer-than-normal temperatures, especially
in low-lying and urban areas. Combined with daytime heating,
elevated moisture, and the effects of local topography, these
conditions will favor the development of showers and isolated
thunderstorms mainly during the afternoon hours when convective
activity is expected to peak, which may lead to localized flooding,
especially in areas where soils are already saturated. Shower
activity is expected to diminish significantly after sunset.
However, overnight rainfall cannot be ruled out, particularly across
eastern Puerto Rico and the U.S. Virgin Islands, due to continued
east-southeasterly flow.

Limited to elevated risks of excessive rainfall, lightning, and heat-
related impacts remain possible in the coming days. For updated
information on potential hazards and areas of concern, please refer
to the Experimental Graphical Hazardous Weather Outlook.

.LONG TERM...Tuesday Through Saturday

The long-term forecast begins with a benign and stable weather
pattern across the islands. At the upper levels, a strong mid- to
upper-level ridge is positioned over western Puerto Rico, placing
the region on the subsident side of the ridge. This synoptic setup
will promote dry and stable atmospheric conditions, further
enhanced by a pronounced trade wind inversion, which will suppress
vertical development of convection and limit significant shower
activity. Despite the stable environment aloft, modest low- to
mid-level moisture between 700 and 500 MB will persist, with
precipitable water (PWAT) values near 1.6 inches, which is
approximately at or slightly below climatological norms. Given
this setup, typical diurnally driven afternoon showers remain
possible, primarily across the interior and western interior of
Puerto Rico. Localized areas may experience moderate rainfall
accumulations, though widespread impacts are not anticipated
during this period.

Deterministic guidance from both the GFS and ECMWF models
suggests a transition to a more unsettled and wetter pattern
beginning Friday. This shift will occur as the mid- to upper-level
ridge weakens and is replaced by increased instability associated
with an upper-level trough propagating eastward from the western
Atlantic into the central Atlantic basin. This upper-level feature
will induce a surface trough, resulting in a change in the low-
level wind flow. Surface winds are expected to shift from the
east-southeast on Friday and veer to a more southerly direction by
Saturday. This shift will advect deeper tropical moisture from the
Caribbean into the region, with PWAT values exceeding 2.0 inches.
The resulting thermodynamic profile will become increasingly
favorable for enhanced convective development, particularly across
the interior and western portions of Puerto Rico, where orographic
and diurnal effects may further enhance rainfall efficiency. At
this time, Friday and Saturday are forecast to be the most active
days within the long-term period. Residents and visitors are
advised to remain attentive to future updates, as evolving
conditions may warrant additional weather advisories or
statements.

&&

.AVIATION...
(06Z)

VCSH and SHRA will continue to affect TJSJ through 10/10Z. SHRA/TSRA
are expected to develop around 10/17Z, particularly across western
and northwestern Puerto Rico. This activity may lead to brief
reductions in visibility and lower ceilings. VCSH and VCTS are
forecast to impact TJBQ beginning around 10/18Z. Winds will remain
variable overnight, becoming east-southeasterly around 10/14Z and
increasing to 15–18 knots, with higher gusts possible near the
heaviest showers.

&&

.MARINE...

A broad surface high pressure system stretching from the central
to the western Atlantic will continue to drive moderate easterly
trade winds across the regional waters. As this high gradually
shifts southward over the next few days, the pressure gradient
will tighten, leading to an increase in wind speeds and building
seas up to 6 feet, especially in offshore waters. Small craft
should exercise caution due to moderate to locally fresh trades
and choppy conditions. Additionally, isolated to scattered
thunderstorms are possible, particularly during the afternoon and
evening hours, potentially resulting in brief periods of stronger
winds, higher seas, and reduced visibility. Mariners are advised
to remain alert to the evolving conditions and consult the latest
marine forecasts.

&&

.BEACH FORECAST...
There is a moderate risk of rip current across the northern
coastal areas of Puerto Rico and the St. Croix. The risk will
remain low to moderate along the coastal areas of the islands. Life-
threatening rip currents often occur near groins, jetties, reefs,
and piers. The moderate risk will expand to most beaches of
Culebra and St Croix, as well as beaches of Vieques and
southeastern PR on Monday.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
522 AM AST Sun May 11 2025

.KEY MESSAGES...

* Another active afternoon is forecast for today with shower
activity along the mountains and western interior.

* An improving weather pattern is forecast from Monday into
Thursday, becoming more unstable and wet by Friday into the
upcoming weekend.

* Breezy conditions will begin today, especially along the coastal
areas.

* A low to moderate risk of rip current along all the coastal.

&&

.SHORT TERM...Today through Tuesday...

Generally, calm weather prevailed overnight across Puerto Rico and
the US Virgin Islands. A few light showers moved through eastern
Puerto Rico, but rainfall amounts were minimal or below 0.50 inches.
Overnight temperatures remained in the mid to upper 70s Fahrenheit
across coastal and urban areas, while higher elevations experienced
cooler conditions, with lows in the high 60s to low 70s. Winds were
light, mainly from the east-southeast.

Looking ahead, model guidance shows that a surface high-pressure
system over the central Atlantic will continue to dominate,
maintaining an east-to-east-southeast wind flow. This will support
slightly warmer-than-normal temperatures, particularly at low
levels, as 925 mb temperatures trend near or slightly above normal.
Tonight through Monday, isolated to scattered showers are expected
to continue during the overnight and early morning hours, especially
over eastern Puerto Rico. During the afternoon, local and diurnal
effects will lead to the development of showers and isolated
thunderstorms mainly across the interior and northwestern sections
of Puerto Rico. There remains an elevated risk for localized
flooding due to these afternoon showers. By Monday into Tuesday, a
mid-level ridge will begin to build over the region, replacing the
influence of a departing shortwave trough and resulting in slightly
more stable weather conditions. Winds will gradually shift to a more
east-northeasterly direction, while moisture levels decrease, with
precipitable water values dropping to between 1.4 and 1.6 inches.
Temperatures aloft will warm slightly to around -6 degrees Celsius,
supporting a more stable atmosphere overall. Although isolated
afternoon showers or thunderstorms will still be possible,
particularly over interior and western areas, activity is expected
to be less widespread and less intense compared to previous days.
Therefore, the risk of flooding for the beginning of the week should
remain limited to none in some areas.


.LONG TERM...Wednesday through Sunday...

The long-term forecast will begin with a generally stable pattern
over the region, under the influence of a mid to upper-level
ridge centered over the western Caribbean and Puerto Rico. This
ridge places the islands on its subsident side, favoring stable
conditions aloft, as supported by rising 250 MB heights and
gradually warming 500 MB temperatures from around -7°C to near
-5°C by the end of the workweek, according to GFS. From midweek
through Thursday, a pronounced trade wind inversion will help
suppress deep convective activity. However, precipitable water
values are expected to range between 1.5 and 1.7 inches, and
700–500 MB relative humidity will increase at around 40 to 50
percent. These values may still support isolated afternoon
showers, particularly across the interior and western Puerto Rico.
Overall instability will remain limited, which will help keep
rainfall coverage and intensity in check. Later in the period,
model guidance shows a transition to a wetter and more unstable
pattern.

As the mid to upper-level ridge weakens, an upper-level
trough will move eastward, lowering 500 MB temperatures and
weakening the trade wind inversion. A surface trough is forecast
to develop as well, shifting winds from the east-southeast to a
more southerly component, which will allow for deeper tropical
moisture to move into the region. As a result, precipitable water
values are expected to exceed 2.0 inches by the weekend. By the
weekend, the environment becomes significantly more conducive to
enhanced convection, with increasing mid-level moisture and a more
unstable atmospheric profile. These conditions will support
widespread showers and thunderstorms, particularly across the
Cordillera Central and western Puerto Rico, aided by diurnal and
orographic effects. This pattern will likely peak in activity
during the weekend, when conditions will favor more organized
convection and higher rainfall totals. Localized flooding is
possible. Residents and visitors should stay alert for updates in
case weather advisories or special statements become necessary.

&&

.AVIATION...
06Z)

VFR conditions are expected to prevail across all terminals through
the morning hours. However, VCSH will affect TJSJ, TIST, and TISX
from time to time through at least 11/12Z. After 11/17Z, SHRA and
isolated TSRA are expected to develop, mainly across W and NW PR,
potentially affecting TJBQ. This convection may result in brief
reductions in visibility and periods of lower ceilings. Surface
winds will remain from the ESE at 10 to 15 knots, with occasional
sea breeze variations in the afternoon.

&&

.MARINE...

The presence of the broad surface pressure extending across most
of the Atlantic Basin will promote more moderate to locally fresh
winds from today into Wednesday. This will favor more choppy
marine weather with winds up to 20 knots. This will lead to an
increase in wind speeds and the building of seas up to 6 feet,
especially in offshore waters. Small craft should exercise
caution across the local exposed waters. Additionally, isolated to
scattered thunderstorms are possible, particularly during the
afternoon and evening hours, potentially resulting in brief
periods of stronger winds, higher seas, and reduced visibility.

&&

.BEACH FORECAST...
There is a moderate risk of rip current along the north coast or
Puerto Rico, Culebra and the St. Croix. The low to moderate risk
will persist for the rest of the weekend into the workweek.
Residents and visitors are urge to stay alert of Life- threatening
rip currents that occur near groins, jetties, reefs, and piers.

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
527 AM AST Mon May 12 2025

.KEY MESSAGES...

* Afternoon showers and thunderstorms will affect western PR and
downwind of the local islands.

* More unstable and wet weather conditions are forecast by Friday
and into the upcoming weekend.

* Breezy conditions will persist for the next few days.

* Increasing winds will lead to choppy to rough seas and a
moderate risk of rip currents.

&&

.SHORT TERM...Today through Wednesday...

Variable weather conditions persisted across the local islands
during the night and early morning hours. Brief showers were
detected by Doppler radar over portions of the eastern region,
leaving minimal rainfall accumulations. Across the western half of
Puerto Rico, mostly clear skies prevailed. Overnight temperatures
remained in the lower 80s along coastal areas and were noticeably
cooler in the mountainous regions.

From today into early Wednesday, the weather pattern is expected
to become more favorable across the CWA as a mid-to-upper-level
ridge establishes itself over the western Atlantic. This feature
will promote drier conditions aloft and a pronounced trade wind
cap inversion, which will limit the vertical development of
stronger showers. At the surface, a broad high-pressure system
over the central Atlantic extending into the Caribbean will
slightly tighten the pressure gradient, resulting in breezier
conditions across the CWA. These conditions will support a stable
but variable weather pattern during the morning, with extended
periods of sunshine and some brief showers over eastern Puerto
Rico and the U.S. Virgin Islands. Although the potential for
significant rainfall is reduced, afternoon convection due to
diurnal heating is forecast across the western interior and nearby
municipalities. Rainfall totals are expected to range between 1
and 2 inches in areas affected by the bulk of the activity, though
fast-moving showers driven by the prevailing trade winds will
likely result in only localized impacts.

A similar pattern is expected on Tuesday; however, GFS model
guidance suggests a slight decrease in precipitable water values
from 0–3 km, down to around 1.1 inches. These drier conditions
indicate that Tuesday may be the most stable day across the
region. By Wednesday, the surface high over the western Atlantic
is forecast to sink southward and interact with an induced
surface trough, resulting in veering winds across the region. This
southeasterly wind flow will lead to an increase in atmospheric
moisture, raising the potential for shower development and
contributing to higher heat index values, marking the beginning of
a warming trend.

.LONG TERM...Thursday through Monday...

Increasingly wet and unstable condtions are forecast during most
of the long term forecast period. After mid-week, current model
guidance has precipitable water (PWAT) values close to around 2
inches, above normal values for this time of the week. A decrease
in PWAT values is forecast by late Sunday and Monday, decreasing
to around 1.8 inches. A mid to upper-level ridge present on
Thursday will gradually weaken as a mid to upper level trough
moves eastward from the western Atlantic towards the local
islands, this will promote more favorable conditions for shower
and thunderstorm development late Thursday onwards. A surface
trough will also develop, also providing instability and
promoting, along with a surface high over the central Atlantic,
more east-southeast to southeast steering flow over the region.
Deep tropical moisture will start to move into the region, with
current model guidance showing a completely moist atmospheric
profile, possibly being somewhat confined once again to below
650mb by late Saturday and into early next week. With the
prevailing wind flow, increased temperatures are also forecast in
areas without significant cloudiness, particularly during the late
morning hours. Ultimately this diurnal heating, along with sea
breeze convergence and local orographic effects, can also help
promote shower and thunderstorm development, adding to the already
unstable atmospheric conditions. By Friday and into the weekend,
conditions will be conducive to increased convective activity.
Widespread showers and thunderstorms are forecast, particularly
across the Cordillera Central and western Puerto Rico, with lines
of convection possibly also developing from the local islands and
El Yunque. With already saturated soils and these moist and
unstable conditions, a limited to elevated flooding risk is
forecast during these days, meaning that urban, small stream and
flash flooding is possible. Stay tuned for any updates.

&&

.AVIATION...

(06Z TAFs)

SFC will will peak at 12/14Z from the E up to 15 knots with gusty
winds up to 30 knots. After 12/18Z localized areas of SHRA/TSRA are
expected with local MVFR conds TJBQ and TJSJ reducing VIS a lowering
flight ceilings. Winds will remain up to 10 k knots after 12/23Z.


&&

.MARINE...

A broad surface high pressure over the Central Atlantic will sink
southward over the next few days, resulting in increasing winds
and choppy conditions across the offshore waters. A Small Craft
Advisory is now in effect for the Atlantic offshore waters and the
Anegada Passage due to seas building up to 7 feet by this
afternoon. Small Craft Should Exercise Caution over most of the
other waters. Thunderstorm activity is likely across the regional
waters, especially in the afternoons and evenings, resulting in
locally higher winds and seas.


&&

.BEACH FORECAST...

There is currently a moderate risk of rip currents for the
northern to eastern beaches of Puerto Rico, from Aguadilla to
Ceiba, as well as for southwestern Puerto Rico, and most of
Culebra, Vieques, St. Croix, St. John and St. Thomas. The moderate
risk of rip currents will extend tonight to areas of southern and
northwestern Puerto Rico tonight. In general, a low to moderate
risk of rip currents will persist through the workweek. Life-
threatening rip currents often occur in the vicinity of groins,
jetties, reefs, and piers.

If you become caught in a rip current, yell for help. Remain
calm, do not exhaust yourself and stay afloat while waiting for
help. If you have to swim out of a rip current, swim parallel to
shore and back toward the beach when possible. Do not attempt to
swim directly against a rip current as you will tire quickly.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
512 AM AST Tue May 13 2025

.KEY MESSAGES...

* Generally stable weather conditions today with afternoon showers
and isolated thunderstorms, driven by local effects, are
anticipated across western Puerto Rico and downwind of the local
islands.

* Breezy conditions will persist for the next few days, mainly
across coastal areas.

* Increasing winds will result in choppy to rough seas and a
moderate risk of rip currents through the end of the workweek.

* A deep layer trough and abundant tropical moisture will promote
wet and unstable weather, with an increased flooding risk, by
Friday and into the upcoming weekend. Stay tuned for updates.

&&

.SHORT TERM...Today trough Thursday....

During the overnight and early morning hours, variable conditions
prevailed across the region. Doppler radar detected isolated
showers over the U.S. Virgin Islands early in the night; these
showers later moved over eastern Puerto Rico, while mostly clear
skies dominated the western half of the island. Rainfall
accumulations associated with these showers were minimal.
Overnight temperatures ranged from the lower 80s along coastal
areas to noticeably cooler values in the mountainous regions.

The short-term forecast remains on track. From today into tomorrow,
stable weather conditions are expected to persist as a mid-to-upper-
level ridge centered over the western Atlantic dominates the local
region, promoting drier air aloft and supporting a trade wind cap
inversion. This ridge will enhance subsidence, thereby suppressing
significant vertical cloud development throughout the day. At the
surface, the synoptic pattern remains similar, with high pressure
over the central Atlantic extending into the region, tightening the
pressure gradient and reinforcing the steering flow. Winds will
remain from the east today. GFS model guidance continues to indicate
a mostly stable weather pattern, with precipitable water (PWAT)
values dropping to around 1.4 inches (near the 25th percentile) and
700–500 mb relative humidity remaining below 60%. These drier
conditions will favor mostly sunny skies during the morning hours,
with only isolated afternoon showers possible across western Puerto
Rico.

By Wednesday afternoon into Thursday, winds are forecast to veer in
response to an induced surface trough associated with an approaching
upper-level trough over the western Atlantic. This shift will
promote increased moisture transport into the region, with PWAT
values rising toward 1.8 to 2.0 inches and relative humidity in the
700–500 mb layer reaching 70–80%. As a result, the potential for
afternoon convection will increase, particularly across the interior
and northwestern Puerto Rico. Although sufficient moisture will be
present to support shower development, 500 mb temperatures are
expected to hover near -4 C, which is nearly +2 standard deviations
above normal; this suggests that thunderstorm activity is not
likely, though one or two isolated thunderstorms cannot be
completely ruled out. Additionally, southeasterly winds will lead to
warmer conditions and increasing heat index values through Thursday,
marking the start of a gradual warming trend.

.LONG TERM...Friday through Tuesday...

Wet and unstable conditions are forecast to end the workweek and
through early next week. A deep layered trough, currently affecting
the western Caribbean and western Atlantic, will gradually move
eastward towards the local islands, this will promote more
favorable conditions for widespread shower and thunderstorm
activity late in the workweek and during the weekend. A surface
trough will also develop, also providing instability and
promoting, along with a surface high over the central to eastern
Atlantic, light east- southeast to southeast surface flow over the
region by Saturday. Deep tropical moisture will also start to
move into the region from the east-southeast, with current model
guidance showing a completely moist atmospheric profile, possibly
being somewhat confined to below 500mb by late in the weekend and
into early next week. By Friday, current model guidance has
precipitable water (PWAT) values around 2.25 inches, above normal
values for this time of the week. A decrease in PWAT values is
forecast by late Sunday and Monday, decreasing to around 1.8 to
1.9 inches, before increasing again to around 2 inches on Tuesday.
A factor that could inhibit this activity is a Saharan Air Layer
that could also reach the islands this weekend. Diurnal heating,
along with sea breeze convergence and local orographic effects,
will also help promote shower and thunderstorm development, adding
to the already unstable atmospheric conditions. Widespread
showers and thunderstorms are forecast, particularly over the
eastern region and interior PR, increasing the risk of urban and
small stream flooding, flash flooding, river rises and debris flow
in steep terrains. With already saturated soils, elevated streams
and these future moist and unstable conditions, a limited to
elevated flooding risk is forecast during these days, further
monitoring will continue and a significant flooding threat can be
forecast soon. Stay tuned for any updates.

&&

.AVIATION...

(06Z TAFS)

VFR conditions will persist along all the TAF sites during the
period. Winds will continue from the E peaking up up to 15 knots
with gusty winds at 13/15Z. VCSH/SHRA are possible near TJBQ at
around 13/19Z, this will reduce the VIS briefly, and it will lower
ceilings.

&&

.MARINE...

A broad surface high pressure over the Central Atlantic will sink
southward over the next few days, resulting in increasing winds and
choppy conditions across the offshore waters. A Small Craft Advisory
is in effect for the Atlantic Offshore and Caribbean Offshore waters
and the Mona and Anegada Passage due to seas building up to 7 feet.
Small Craft Should Exercise Caution over most of the other waters.
Thunderstorm activity is likely across the regional waters,
especially late in the workweek and into the weekend, resulting in
locally higher winds and seas.

&&

.BEACH FORECAST...

There is a moderate risk of rip currents today for the northern
to eastern beaches of Puerto Rico, from Rincon to Ceiba, as well
as for southeastern Puerto Rico, sectors of southwestern Puerto
Rico, and most of Culebra, Vieques, St. Croix, St. Thomas and St.
John. In general, a low to moderate risk of rip currents will
persist through the workweek, before becoming low on Saturday.
Life- threatening rip currents often occur in the vicinity of
groins, jetties, reefs, and piers.

If you become caught in a rip current, yell for help. Remain
calm, do not exhaust yourself and stay afloat while waiting for
help. If you have to swim out of a rip current, swim parallel to
shore and back toward the beach when possible. Do not attempt to
swim directly against a rip current as you will tire quickly.

&&

.HYDROLOGY...

Forecast models continue to indicate the development of another wet
and unstable weather period in recent updates. By the end of the
workweek, increasing atmospheric instability, combined with abundant
tropical moisture, is expected to result in widespread thunderstorm
activity, with some storms capable of producing heavy rainfall. This
pattern will be driven by the interaction between a deep-layered
trough and unusually high precipitable water values for this time of
year, ranging from approximately 2.0 to 2.25 inches. The wet and
unstable weather pattern is expected to persist through the weekend.

Prolonged periods of moderate to heavy rainfall will increase the
risk of urban and small stream flooding, flash flooding, and
mudslides in areas of steep terrain. Additionally, significant
runoff from excessive rainfall could result in quick river rises,
with some rivers potentially exceeding flood-stage levels. Soils
remain saturated and streamflows elevated due to the extended wet
period experienced in recent weeks. These antecedent conditions will
further exacerbate the aforementioned impacts across the region.
Residents and visitors, especially those in flood-prone areas or
planning outdoor activities, are advised to closely monitor the
latest weather forecasts and updates.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
508 AM AST Wed May 14 2025

.KEY MESSAGES...

* An approaching trough and a surge in tropical moisture will
result in a gradual transition to a wet and unstable weather
pattern, with and increased flooding risk, through the end of
the workweek and the weekend.

* Breezy to locally windy conditions will persist for the next
few days.

* Increasing winds will result in choppy to rough seas and a
moderate risk of rip currents through the end of the workweek.

&&

.SHORT TERM...Today through Friday...

Overnight conditions were relatively quiet across the region.
However, an increase in cloud cover and trade wind showers was
observed as a plume of tropical moisture continued to spread across
the area. Strengthening easterly winds allowed some of these showers
to push farther inland, reaching the central interior of Puerto
Rico. Radar estimates indicated isolated rainfall totals of around
three-quarters of an inch, mainly over eastern Puerto Rico. Winds
ranged from 5 to 15 mph in windward areas, while lighter and more
variable conditions prevailed inland and across leeward areas.
Minimum temperatures dropped to around 60°F in higher elevations,
with the local island remaining near 80°F.

Looking ahead, a gradual transition to a wetter and more unstable
weather pattern is expected through the end of the week, with Friday
likely being the most active day. A broad high-pressure system over
the North Atlantic will maintain breezy to locally windy conditions
today, steering trade wind showers across windward coastal areas,
especially overnight and early mornings. Meanwhile, a weakening
ridge and an approaching trough from the west-northwest will also
interact with a surge of tropical moisture from the southeast. As a
result, precipitable water values will climb sharply, from below 1.5
inches to above 2.0 inches by tonight, promoting deep-layer moisture
and an increasingly humid, unstable atmosphere.

Rainfall activity today is expected to remain relatively localized,
mainly affecting northwestern Puerto Rico. However, as moisture
levels and upper-level support improve, showers and thunderstorms
are forecast to become more widespread and intense on Thursday and
Friday. With PWAT values peaking near 2.2 inches and 500 mb
temperatures dropping to around -8 °C, conditions will be favorable
for moderate to heavy rainfall periods. While Saharan dust and cloud
cover may limit some convective development, the overall risk for
urban and small stream flooding—and potentially isolated flash
flooding—will increase. A Hydrologic Outlook may be issued in the
coming days, with a Flash Flood Watch possible if forecast
confidence continues to grow. Residents and partners are encouraged
to stay informed and monitor future updates, including the
Experimental Graphical Hazardous Weather Outlook for evolving hazard
information.

.LONG TERM...Saturday through Wednesday...

A wet and unstable weather pattern is forecast Saturday through
early next week. A deep layered trough, currently over the western
Caribbean and western Atlantic, will gradually move eastward
towards the local islands, this feature will promote more
favorable conditions for widespread shower and thunderstorm
activity during the weekend. A surface trough will also develop,
also providing instability and promoting, along with a surface
high over the central to eastern Atlantic, light east- southeast
to southeast surface flow over the region to start the period.
These features will converge with deep tropical moisture that will
also be over the region and will continue to arrive from the
east- southeast, with current model guidance showing a completely
moist atmospheric profile, possibly being somewhat confined to
below 500mb by late Sunday and into early next week. By Saturday,
current model guidance continues to indicate precipitable water
(PWAT) values around 2.25 inches over the islands, above normal
values for this time of the week. A slight decrease in PWAT values
is forecast at times during the period but will increase again to
around 2 inches. A limiting factor for this activity could be
Saharan Air Layer that could also reach the islands this weekend.
Although PWAT values will continue to be elevated, the deep layer
troughs influence will not be as pronounced Tuesday and Wednesday.
Widespread showers and thunderstorms are forecast particularly
over the eastern region and interior PR and with already saturated
soils and elevated streams, there is an increased risk of urban
and small stream flooding, flash flooding, river rises and debris
flow in steep terrains. Up to an elevated flooding risk is
forecast during these days. Further monitoring will continue and
a significant flooding threat may be added and a Hydrologic
Outlook may be issued soon, a Flash Flood Watch is also possible.
Stay tuned for any updates.

&&

.AVIATION...

(06Z TAFs)

Generally, VFR conditions are expected across all TAF sites,
though brief MVFR conditions are possible due to trade wind
showers and afternoon SHRA/TSRA. While the chance for MVFR
conditions will persist at TJSJ and USVI terminals, TJBQ and TJPS
may experience MVFR conditions after 14/16Z and 14/22Z,
respectively. Easterly winds will range from 5–10 knots,
increasing to 15–20 knots after 14/13Z, before becoming light and
variable after 14/22Z. Higher gusts are possible in and near
SHRA/TSRA.

&&

.MARINE...

A broad surface high pressure over the Central Atlantic will
promote breezy easterly winds that will result in choppy
conditions across the offshore waters. A Small Craft Advisory is
in effect for the Offshore Atlantic and Anegada Passage through at
least this evening due to seas building up to 6 to 7 feet. Small
Craft Should Exercise Caution over most of the other local waters.
A deep trough will promote an unsettled weather pattern with a
high chance for thunderstorm development from Thursday afternoon
onward, resulting in locally higher winds and seas.


&&

.BEACH FORECAST...

There is a moderate risk of rip currents today for the northern
to eastern beaches of Puerto Rico, from Aguadilla to Ceiba, as
well as for southeastern Puerto Rico, sectors of southwestern
Puerto Rico, and most of Culebra, Vieques, St. Croix, St. Thomas
and St. John. In general, a low to moderate risk of rip currents
will persist through the workweek, before becoming mostly low on
Saturday and Sunday. Life- threatening rip currents often occur
in the vicinity of groins, jetties, reefs, and piers.

If you become caught in a rip current, yell for help. Remain
calm, do not exhaust yourself and stay afloat while waiting for
help. If you have to swim out of a rip current, swim parallel to
shore and back toward the beach when possible. Do not attempt to
swim directly against a rip current as you will tire quickly.

&&

.HYDROLOGY...

Abundant tropical moisture and a lingering trough will enhance the
potential for showers and thunderstorms across Puerto Rico and the
Virgin Islands by the end of the workweek and into the weekend.
Soils are saturated (with soil saturation > 80%), and streams are
running at normal to above-normal levels, heightening the risk of
flooding. Rainfall could range from 2-4 inches each day, with the
highest risk expected on Friday and Saturday. As winds weaken over
the weekend, any rainfall that develops will persist longer,
increasing the risk of mudslides, rapid river rises, and isolated
flash flooding. While there is some uncertainty related to increased
cloud cover and Saharan dust particles limiting rainfall
development, the overall period is expected to remain unsettled.
Residents and visitors are urged to stay informed for updates.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
518 AM AST Thu May 15 2025

.KEY MESSAGES...

* A wet and unstable weather pattern will continue through the
end of the workweek and the weekend, heightening the risk of
flooding across Puerto Rico and the U.S. Virgin Islands,
especially on Friday and Saturday.

* Breezy winds will maintain choppy to rough seas, with a moderate
risk of rip currents through at least Saturday.

* Suspended Saharan dust will begin moving into the region on
Friday, resulting in hazy skies in areas with little or no
rainfall.

&&

.SHORT TERM...Today through Saturday...

A transition into a wet and unstable pattern continues to be
forecast as we head towards the end of the week. A deep layered
trough, currently west-northwest of our local islands, will
gradually move eastward and promote more favorable conditions for
widespread shower and thunderstorm activity, especially late
Thursday onwards. East- southeast steering flow over the region will
persist during the period and continue to bring a surge in moisture
over the islands. The deep layered trough will converge with this
deep tropical moisture that will arrive from the east- southeast,
with current model guidance showing a completely moist atmospheric
profile. Current satellite derived precipitable water values are
currently at around 1.8 to more than 2.0 inches above most of the
region. Current model guidance continues to indicate precipitable
water (PWAT) values around 2.25 inches over the islands, above
normal values for this time of the year with slight decreases in
PWAT values at times.Current model guidance also has the trough
moving quicker than before, but still affecting the local islands.

As they were during the early morning hours, trade wind showers (and
possible isolated t-storms) will continue to affect windward sectors
of the islands from the southeast during this morning, while this
afternoon convection is forecast mainly over NW PR and downwind of
El Yunque and the local islands but more generalized than yesterday.
A broad high-pressure system over the Atlantic will continue to
maintain generally breezy conditions today and tomorrow, gradually
decreasing on Saturday. 925 mb temperatures will be at normal values
through late Friday, when they are forecast to drop to below normal
values.

With moisture and instability increases (500mb temperatures dropping
to around -7 to -8C), showers and thunderstorms are forecast to
become more widespread as the week continues, particularly on Friday
into Saturday, over southeastern and eastern Puerto Rico, Vieques,
Culebra, and the U.S. Virgin Islands. There is a moderate chance (40-
60%) of receiving 2 to 4 inches across these areas with locally
higher amounts of up to 6 inches each day. A Saharan Air Layer
continues to approach the islands and could be a limiting factor
(along with cloud coverage) for this wet pattern during the short
term period. With already saturated soils and elevated streams,
there is an increased risk of urban and small stream flooding,
potentially isolated flash flooding, river rises and debris flow in
steep terrains. Please refer to the latest Hazardous Weather Outlook
and the latest Hydrologic Outlook for more information.

.LONG TERM...Sunday through Wednesday...

Despite recent model guidance introducing a few notable changes, a
dynamic interplay between upper-level and surface features will
continue to drive periods of marginal instability and variable
winds across the northeastern Caribbean. A Tropical Upper
Tropospheric Trough (TUTT) Low and its associated surface-induced
trough will dominate on Sunday, with its divergent side supporting
cooler-than-normal 500 mb temperatures and a weakened trade wind
inversion, favorable for deep convection. As the TUTT Low lifts
northeastward, a large upper-level trough digging into the western
Atlantic will reinforce this pattern, while a developing mid-
level ridge emerges far to the west.

At the surface, the induced trough will continue to disrupt the
trade wind flow, even after detaching from its parent feature,
maintaining lighter, more variable winds through the period.
Meanwhile, a broad surface high over the central North Atlantic
and a weaker high near the Bahamas will help trap tropical
moisture across the region. On Sunday, precipitable water values
may reach up to 2.0 inches. As the weak high lifts northeastward
and pushes the moisture southeastward, a gradual drying trend is
anticipated, with a return of deeper moisture expected by
midweek as strengthening east-southeasterly winds reestablish.

During this period, Puerto Rico will experience fluctuating
moisture levels and variable wind patterns early on, while
generally moist and breezy conditions are expected to persist
longer over Vieques, Culebra, and the U.S. Virgin Islands. Despite
these variations, the overall moist and marginally unstable
environment will enhance shower and thunderstorm development,
particularly during the afternoon. Slackened winds will reduce
ventilation, allowing convective cells to linger longer and
increasing the risk of locally heavy rainfall and flooding.


&&

.AVIATION...
(06Z TAFs)

Generally VFR conditions across the TAF sites with brief MVFR
conditions possible due to trade wind SHRA and afternoon SHRA/TSRA,
affecting TJSJ/TISX, the TJPS (or its VCTY) and, during the
afternoon (after 15/16z), TJBQ. E-SE steering winds will increase to
15–20 kts after 14/13Z, becoming light and variable after 15/22Z
(however higher gusts are possible in and near SHRA/TSRA).


&&

.MARINE...

A broad surface high pressure over the Central Atlantic will
promote breezy easterly winds. As a result, small craft operators
should exercise caution due to choppy conditions through Friday
night across most local waters. A surface trough will gradually
weaken winds over the weekend into early next week. Meanwhile, a
deep trough will bring an unsettled weather pattern with a high
chance of thunderstorm development beginning Thursday afternoon,
leading to locally higher winds and seas.


&&

.BEACH FORECAST...

Life-threatening rip currents are possible along most northern,
southern, and eastern exposed beaches of the islands today and
tonight. The risk will likely diminish this weekend as winds ease
gradually. For more information, please refer to the latest
Coastal Hazard Message (CFWSJU) and Surf Zone Forecast (SRFSJU).

Shower and thunderstorm activity will likely increase by the end
of the week and continue into the weekend as the region
transitions back to a wet and unstable weather pattern. Reminder:
Seek shelter and leave the water or beach immediately at the
first sign of thunder or lightning.


&&

.HYDROLOGY...

Due to abundant moisture and increasing instability associated
with an upper-level trough, the risk of flooding across Puerto
Rico and the U.S. Virgin Islands is increasing for Friday and
Saturday. The heaviest rainfall is currently expected across
southeastern and eastern Puerto Rico, Vieques, Culebra, and the
U.S. Virgin Islands, where 2 to 4 inches of rain are likely, with
locally higher amounts possible. Saturated soils and elevated
river levels will enhance the threat of urban and flash flooding,
river flooding, and mudslides, particularly across central and
eastern Puerto Rico. For additional details, refer to the
Hydrologic Outlook (ESFSJU). If forecast confidence and risk
continue to increase, a Flash Flood Watch may be issued later
today or tonight.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
515 AM AST Fri May 16 2025

.KEY MESSAGES...

* Abundant tropical moisture and a strong upper-level trough to the
west will bring an unsettled weather pattern, increasing the
risk of excessive rainfall impacts across Puerto Rico and the
U.S. Virgin Islands, especially on Friday and Saturday.

* Breezy winds will maintain choppy to rough seas, with a
moderate risk of rip currents through at least late tonight.

* Saharan dust will continue to filter the region, resulting in
hazy skies in areas with little or no rainfall.


&&

.SHORT TERM...Today through Sunday...

A deep layered trough, currently over La Espanola and the Mona
Passage, will continue to gradually move eastward towards our region
and promote more favorable conditions for widespread shower and
thunderstorm activity, and generally wet and unstable conditions,
while lso ehancing the diurnal convective pattern each afternoon.
East- southeast steering flow over the region will persist during
the period, although interrupted by and induced surface trough, and
continue to bring increased moisture over the islands. Current model
guidance indicates less precipitable water (PWAT) totals over the
region than previous runs, but still indicate normal to above normal
values for this time of the year with slight decreases at times. The
deep layered trough from the west will converge with this deep
tropical moisture from the east-southeast. This trough and possible
TUTT low, will gradually start to move away from the area late in
the period. A broad surface high pressure system over the Atlantic
moving further into the central Atlantic will continue to maintain
generally breezy conditions today, gradually decreasing on Saturday.
925 mb temperatures are forecast to drop to below normal values
through Sunday night, where they return to normal values.

With moisture and instability (500mb temperatures droping to around
-7 to -8.5C) increasing, showers and thunderstorms are forecast to
become more widespread as we continue through the short term period,
particularly over northwestern, interior, southeastern and eastern
Puerto Rico, Vieques, Culebra, and the U.S. Virgin Islands. However,
a Saharan Air Layer will continue to filter into the local area
during the short term period resulting in hazy conditions. will be
present across the USVI and PR. This could be a limiting factor
(along with cloud coverage) for this wet pattern during the short
term period. Current model guidance does show a slight delay in the
arrival of the bulk of the Saharan Air Layer, compared to previous
runs and we continue to lean towards a wetter forecast during the
period. With already saturated soils and elevated streams, there is
up to an elevated risk of urban and small stream flooding,
potentially isolated flash flooding, river rises and debris flow in
steep terrains. Please refer to the hydro section below, the latest
Hazardoud Weather Outlook and the latest Hydrologic Outlook for more
information.

.LONG TERM...Monday through Thursday...

Recent model guidance shows no significant changes. A dynamic
interplay between upper-level and surface features will continue
to drive periods of marginal instability across the northeastern
Caribbean. A Tropical Upper Tropospheric Trough (TUTT) Low will
keep lifting northeastward and will likely exit the region by
Monday. A second short-wave upper-level trough will follow,
settling into the region starting Tuesday. This second feature
will help sustain the developing mid-level ridge over the western
Caribbean, reinforcing a marginally unstable weather pattern
across the local area.

At the surface, a weakening induced trough will continue to
disrupt the trade wind flow, keeping winds lighter and more
variable early in the week. A broader surface high over the
central North Atlantic will help trap tropical moisture across the
eastern Caribbean, while a weaker high lifting northeastward over
the western Atlantic will help push most of that moisture south
of the local islands. As this high dissipates, east-southeasterly
winds will likely strengthen and become more established by
midweek, continuing through the latter part of the week. This
pattern shift will not only support a gradual increase in tropical
moisture but may also lead to warmer-than-normal conditions.

The combination of moisture and marginal instability will continue
to favor shower and thunderstorm development, especially in the
afternoons, due to daytime heating and local effects. Starting
Wednesday, conditions will likely become more favorable for deeper
thunderstorm activity as 500 mb temperatures drop to near-normal
levels for this time of year, below -6 °C, through the second half
of the week. Light winds, particularly through Tuesday, will
limit storm movement and ventilation, allowing showers and storms
to linger longer over the same areas, increasing the potential for
locally heavy rainfall and flooding.

Meanwhile, Saharan dust will continue over the region, with
concentrations likely peaking on Monday. This could temporarily
suppress rainfall and lower air quality, especially across the
Virgin Islands and eastern Puerto Rico.


&&

.AVIATION...
(06Z TAFs)

Generally VFR conditions across the TAF sites with MVFR conditions
possible due to trade wind SHRA and afternoon SHRA/TSRA, affecting
TJSJ/TISX/TIST/TJPS and, TJBQ (after 16/16z). E-SE steering winds
will increase to 15–20 kts after 16/14Z, becoming light and variable
after 16/22Z (however higher gusts are possible in and near
SHRA/TSRA). In general, SHRA/TSRA is expected to increase during the
period while minor concentrations of Saharan dust will also filter
in.le in and near SHRA/TSRA).


&&

.MARINE...

A broad surface high pressure over the central Atlantic will
continue to promote moderate to locally fresh easterly winds
through tonight. As a result, small craft should continue to
exercise caution. Over the weekend and into early next week, a
surface trough will gradually weaken these winds. At the same
time, a deep trough to the west of the region will support an
unsettled weather pattern, with a high chance of thunderstorm
development through at least Saturday. These storms could lead to
locally higher winds and seas. In addition, hazy conditions are
likely over the weekend due to the presence of Saharan dust.


&&

.BEACH FORECAST...

Life-threatening rip currents are possible along most northern and
east-southeast exposed beaches of the islands today and tonight.
The risk will likely diminish by Saturday as winds ease gradually.
However, moderate rip current risk will likely return for Saint
Croix early next week. For more information, please refer to the
latest Coastal Hazard Message (CFWSJU) and Surf Zone Forecast
(SRFSJU).

Shower and thunderstorm activity will likely increase by the end
of the week and continue into the weekend as the region
transitions back to a wet and unstable weather pattern. Reminder:
Seek shelter and leave the water or beach immediately at the first
sign of thunder or lightning.


&&

.HYDROLOGY...

Abundant moisture and increasing instability associated with an
approaching upper-level trough will heighten the risk of flooding
across Puerto Rico and the U.S. Virgin Islands today and Saturday.
With already saturated soils and elevated river levels in some
areas, any additional heavy rainfall could lead to urban and flash
flooding, river flooding, and landslides, even after the heaviest
rain has ended. For more details, please refer to the Hydrologic
Outlook (ESFSJU).