Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Tue Feb 25 2025

.SYNOPSIS...

A variable weather pattern is forecast for today with the arrival
of moisture and cloudiness across the islands and the influence of
a pre-frontal trough. Improving marine and coastal conditions
will persist with a moderate risk of rip currents.

&&

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

Cloudy skies persisted through the overnight period, and frequent
showers have been moving primarily across the eastern and
southeastern regions of Puerto Rico and the surrounding islands.
Based on Doppler radar estimates, around 0.10 to 0.35 inches of
rainfall had fallen as of 430 AM AST. Winds are predominantly from
the southeast at 10 knots or less, with variations due to land-sea
breeze effects. Surface observations recorded overnight temperatures
in the low to mid-70s along coastal and lower elevation areas, and
in the low 60s across the mountains of Puerto Rico. Temperatures
ranged in the 70s across the U.S. Virgin Islands.

During the short-term period, weather conditions are expected to
remain showery and variable. The main features include a surface
frontal boundary over the western Atlantic, extending from that area
through Cuba, as well as mid-level ridging to our northeast. As the
boundary approaches from the northwest, a southeast steering wind
flow will prevail through at least Wednesday (tomorrow). This change
in the winds will continue to push a surface perturbation located
southeast of Puerto Rico and St. Croix over the region today. As a
result, the latest model guidance suggests an increase in
precipitable water values, up to 1.60-1.70 inches, which is
considered above the climatological normal. For today, expect an
increased frequency of trade wind showers, particularly across the
southeast and southern areas of Puerto Rico, and potential afternoon
convective development, which could result in periods of moderate to
locally heavy rainfall. Note that the flood threat is expected to
remain limited, with the main risks being ponding of water on
roadways and in poorly drained areas. Residents and visitors are
urged to monitor the forecast and exercise caution on the roads.

A similar weather pattern is expected to persist through the rest of
the forecast period, as moisture convergence dominates over the
area. By Thursday, precipitable water values are forecast to
slightly decrease to average levels, allowing for less rain
accumulations. With the southeasterly winds, there is an increasing
tendency for 925 MB temperatures to rise to the 75th percentile
today and Thursday, peaking up to two standard deviations by
Wednesday. This will likely result in slightly warmer temperatures
across the area, keep that in mind if planning outdoor activities.

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

The weather is expected to become more unstable during the first
part of the long-term forecast. An upper-level subtropical trough
will enhance instability aloft, creating favorable conditions for
shower development. At the surface, a broad high-pressure system
anchored over the central Atlantic will promote an east-
southeasterly wind flow across the region. Global model guidance
continues to indicate the arrival of a wind surge with
precipitable water (PWAT) levels at +2 standard deviations above
normal. This increase in moisture, combined with instability and
relative humidity trapped between 850-500 MB, along with colder
temperatures at 500 MB, will likely lead to more intense showers
across the islands. Most models predict a wet pattern from Friday
into Saturday. However, the NASA Goddard Earth Observing System
Model V5 suggests a slight increase in Saharan dust particles,
which could lead to hazy skies in some areas, affecting
visibility.

Instability is expected to persist throughout the
remainder of the long-term period. A significant development is
the establishment of a 500 MB ridge, which will result in a trade
wind cap and warmer temperatures at mid to upper levels.
Additionally, drier air masses will begin to move in and out
during this time, interspersed with patches of shallow moisture.

&&

.AVIATION...
(06Z)
VFR conditions are expected for the next hours. However, VCSH and
SHRA are expected to approach TAF sites terminals causing BKN cigs,
mountain obscuration, and reduced vis at times mainly aft 25/14z
through 05/20-21Z. SE winds will persist at 15-20 kt with sea breeze
variations and higher gusts aft 25/14z. SE winds at around 10 kts or
less aft 25/23Z.

&&

.MARINE...

A broad surface of high pressure anchored over the northeastern
Atlantic extends into the Central Atlantic, and a front moving
from the western Atlantic into the Central Atlantic will turn
winds more from the southeast today into the rest of the workweek.
Shower activity will increase through midweek as the front moves
closer to the area and a surface trough develops over the
northeastern Caribbean.

&&

.BEACH FORECAST...
Improving coastal conditions will be present along the north
coastal areas of Puerto Rico with a moderate risk of rip currents.
Similar coastal conditions will prevail in the coming days.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
451 AM AST Wed Feb 26 2025

.SYNOPSIS...

For today, the islands will experience a more variable weather
pattern with some cloudiness and southeasterly winds. These actual
conditions will result in cloudiness and showers over the
southeastern and southern sections of the islands and slightly
warmer temperatures across the northern coastal areas. For Friday
into Saturday, an increase in moisture will increase the frequency
in the shower activity once again across the CWA.

&&

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

Satellite imagery showed partly cloudy skies overnight. Passing
showers have been moving primarily across the eastern and southern
sectors of Puerto Rico. Doppler radar estimated maximum
accumulations around 0.10 to 0.25 inches of rainfall. Mainly
southeast winds prevailed at 10 to 15 knots or less. Surface
observations recorded overnight temperatures in the mid to upper 70s
along coastal and lower elevation areas, and in the mid 60s across
the mountains of Puerto Rico. Temperatures ranged in the upper 70s
across the U.S. Virgin Islands.

During the short-term period, weather conditions are expected to
remain showery and variable. The pattern remains on track: an
amplifying surface low over the western Atlantic will continue to
move northeast today, while its associated frontal boundary,
extending from the western Atlantic all the way down into eastern
Cuba, is expected to remain northwest and north of our region
throughout the short-term period. This weather pattern, accompanied
by a surface high pressure across the central and eastern Atlantic,
will support the continuation of a southeast steering wind flow
through this evening and moisture convergence across the region over
the next few days. Precipitable water content is expected to
fluctuate between 1.5 and 1.7 inches today, which is considered
above climatological levels. Consequently, today we can expect
similar weather conditions to yesterday, but models are in agreement
that accumulations should be slightly lighter. Overall, expect an
increased frequency of trade wind showers, particularly across the
southeast and southern areas of Puerto Rico, with potential
afternoon convective development over the northwest later in the
afternoon, enhanced by diurnal heating and sea breeze variations,
which could result in periods of moderate to locally heavy rainfall.
Note that the flood threat is expected to remain limited, with the
main risks being ponding of water on roadways and in poorly drained
areas, but residents and visitors are still urged to exercise
caution on the roads. With the southeasterly winds, the latest
models continue to suggest an increasing tendency in the 925 MB
temperatures, peaking up to two standard deviations today during the
early afternoon and returning to the 75th percentile by Thursday,
which is still considered above climatological levels for this time
of year. As a result, expect an increase in temperatures across the
area over the next few days. By Thursday, precipitable water values
are forecast to slightly decrease to average levels as winds shift
more from the east and patches of drier air with low concentrations
of Saharan dust begin to pull into the area. This will allow a break
from rain during the day; however, western municipalities will
likely experience some afternoon convection due to available
moisture and local effects, but rainfall accumulations are expected
to be lesser. By the end of the week, an upper-level subtropical
trough will enhance instability aloft, creating favorable conditions
for shower development. Combined with a surface trough and
increasing precipitable water values, a day of wet and unstable
conditions is anticipated.

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

For the long-term forecast, a variable weather pattern will
persist across the CWA. For Saturday, global model guidance
continues to show plenty of moisture, with precipitable water
(PWAT) levels in the 75th percentile. This increase in humidity
trap in the 850-500 MB, combined with some of the diurnal and
local effects, will likely lead to more intense showers across the
islands, especially across the eastern sections of Puerto Rico in
the morning hours. At mid-day on Saturday, the bulk of the
moisture will be out of the region, and a drier airmass with some
Saharan Dust particles will move in, eroding the potential for
shower development.

By Monday into the rest of the workweek, a dominant mid-level
ridge will continue to promote mostly stable conditions. However,
some instability will be present at the upper level due to an
upper-level trough. At the surface, a broad surface high pressure
over the Central Atlantic will continue to impulse pulses of
shallow moisture, enhancing a variable weather pattern during the
period. Residents and visitors should prepare for a variable
weather pattern with showers in the morning over eastern PR and
across the mountains in the afternoon hours. On Monday, some
particles of Saharan dust will move into the region resulting in
hazy skies.

&&

.AVIATION...
(06Z TAFs)

Mainly VFR conditions are expected this period. However, VCSH and
possible -RA/SHRA are expected to approach TAF sites terminals
causing intermittent BKN cigs, mountain obscuration, and reduced vis
at times, mainly TJBQ around 26/17-22. SE winds will persist at 10
to 15 kt with sea breeze variations, becoming E-SE and lighter aft
26/23Z.

&&

.MARINE...

A front moving from the western Atlantic into the central
Atlantic will turn winds more from the south-southeast this
morning, and then winds will return from the east-southeast later
today. Shower activity will increase through midweek as the front
moves closer to the area and a surface trough develops over the
northeastern Caribbean. Additionally, a surface high pressure
across the central Atlantic will tighten the local pressure
gradient, promoting moderate to locally fresh easterlies from
Friday onward.

&&

.BEACH FORECAST...

Improving coastal conditions will be present along the north
coastal areas of Puerto Rico with a moderate risk of rip currents.
Similar coastal conditions will prevail in the coming days.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
509 AM AST Thu Feb 27 2025

.SYNOPSIS...

A mass of air with low concentrations of saharan air particulates
approaches the region. Showers will still affect the islands and
eastern Puerto Rico during the morning hours and afternoon
convective showers will affect western Puerto Rico. Another surge
of moisture will result in a wet and showery weather pattern late
Friday night into Saturday. Winds will increase and become more
east- southeast during the weekend. A low to moderate risk of rip
currents is forecast during the next few days.

&&

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

A variable weather pattern prevailed across the local islands during
the overnight into the early morning hours. At 1 AM, the Doppler
Radar showed isolated to scattered showers affecting northwestern
municipalities, leaving almost half an inch in rainfall accumulations.
Shower activity prevailed over the local waters for the rest of
the early morning hours and affected St. Thomas. Overnight minimum
temperatures remained in the low 70s along the mountains and in
the upper 70s to the low 80s across the coastal areas.

A wet and unstable weather pattern will be present for the rest of
the day. At the surface, the proximity of a pre-frontal trough from
a frontal boundary north of the region, interacting with a broad
surface high pressure, will enhance light and easterly wind flow.
Under this wind pattern, moisture will enhance low-level convergence
showers for the rest of the morning into the afternoon hours. Shower
activity will remain relatively frequent in the morning along the
eastern coastal areas, developing over the interior sections for the
afternoon hours.

A rapidly drying trend will appear as a drier airmass with particles
of Saharan Dust moved into the area this afternoon. PWAT values of
that slot of drier air remain in the 1.17 to 1.23 inches as
suggested by the Satellite-derived Imagery from the GOES. Therefore,
residents and visitors could expect mostly hazy skies and limited
showers from this evening into the evening. On Friday into Saturday,
a more southeasterly wind flow will be present as the frontal
boundary moves more into the Central Atlantic and the pre-frontal
stalls just over the western Caribbean. Under this surface wind
pattern, patches of moisture trapped in the 850-500 Mb will continue
to reach the islands, leaving a variable weather pattern.

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

For the next week, a variable weather pattern is forecast. Current
model guidance suggests that both pockets of more humid and
pockets of drier air will reach the region Sunday through Monday.
Low saharan dust concentrations will also move into the region
late Sunday into Monday, resulting in hazy skies. In the mid to
upper levels, a ridge will dominate throughout the first few days,
before an upper level trough approaches the islands from the
north Wednesday and into Thursday, increasing instability. A
series of surface highs and frontal lows will move into the
western to central Atlantic during the period, resulting in east-
southeast flow over the islands, with model guidance suggesting
more south-southeast flow Wednesday into Thursday. East-southeast
flow will steer more frequent patches of moisture into our area by
Tuesday onwards. Precipitable water (PWAT) values will be above
1.5 inches (above normal) with these moist patches. With the more
southerly flow Wednesday and Thursday, current model guidance
suggests PWAT values increasing towards near 2 inches. Available
moisture should be confined to below 700 mb, Sunday and Monday,
gradually moving above it to around 500 mb afterwards. The
variable weather pattern will include overnight and early morning
showers steered towards along eastern and southern coastal
sections of the islands with afternoon convection expected focused
across the central interior and north/northwest sectors of Puerto
Rico. With the approach of an upper-trough and increasing
moisture, a boost in this pattern is forecast by midweek. 925 mb
temperatures will be up to above normal values during the period.

&&

.AVIATION...

(06Z TAFs)

VFR conditions are expected to prevail across all TAF sites through
the forecast period. VCSH to -RA will prevail during the day
resulting in lowering ceiling and reduction in VIS. Winds will
increase at around 27/15Z from the E at 15 knots with gusty winds
near showers.

&&

.MARINE...

A pre-frontal trough from a frontal boundary north of the region,
interacting with a broad surface high pressure over the Atlantic,
will promote light to moderate enhance light to moderate east to
east-southeast winds. As the surface high pressure builds across the
central Atlantic the local pressure gradient will tighten, promoting
a moderate to locally fresh east-southeast wind flow throughout the
weekend.

&&

.BEACH FORECAST...

A moderate risk of rip currents remains today and tonight for the
north oriented beaches of Puerto Rico, from Aguadilla to Rincon,
northern Culebra and easternmost St. Croix. The risk for rip
currents is low elsewhere, however, life-threatening rip currents
often occur in the vicinity of groins, jetties, reefs, and piers.
A low to moderate risk of rip currents is forecast through the
weekend.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
448 AM AST Fri Feb 28 2025

.SYNOPSIS...

Shower activity will continue to reach windward sectors this
morning as patches of moisture filter in and a trough is near the
region. During the afternoon, stronger shower activity is
forecast for mainly northwestern Puerto Rico. Saturday looks like
a transition day as a wide area of drier air approaches from the
Lesser Antilles. As the environment dries out, minor
concentrations of Saharan dust will filter in, creating hazy
skies. East- southeast winds will increase during the weekend. A
mid to upper- level trough will approach the northeast Caribbean
during the early to mid part of the next workweek, followed by a
surface frontal boundary by the end of the next workweek.

&&

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

A small area of moisture approached St. Croix around midnight, and
eastern Puerto Rico early in the morning hours. These showers were
not strong, only leading to wet roads and ponding of water in low-
lying areas. Temperatures cooled down to the low and mid-70s in
coastal areas, and into the low 60s (cooler in isolated spots) in
the mountain. Right now, the axis of the surface trough is centered
just to the south of Puerto Rico, hence winds have shifted from the
southeast. This feature will move additional showers into the Virgin
Islands and eastern Puerto Rico this morning.

At the low and mid levels, high pressure centered over the eastern
Atlantic will keep these winds coming from the southeast through the
forecast period. Today, near normal moisture will combine with
diurnal heating, creating streams of showers that will reach the
Virgin Islands, and the east and northwest of Puerto Rico, as well
as the San Juan metropolitan area. The heaviest activity is
anticipated for the northwest, where minor urban and small stream
flooding could develop. Saturday looks like a transition day between
the moisture brought by the surface troughs and a wide area of drier
air approaching from the Lesser Antilles. It is likely that showers
will also develop Saturday afternoon, but more confined to the
northwestern quadrant of Puerto Rico. As the environment dries
out, minor concentrations of Saharan dust will filter in, creating
hazy skies. These conditions will continue into Sunday, with some
brief shower interruptions, particularly for the easternmost
sections of Puerto Rico, as well as the Virgin Islands.

It will be warmer than normal too, especially during the afternoon
hours. The 925-mb temperature values are about one standard
deviation above the climatological mean. Even with cooling still
happening in the overnight hours, the highs will climb to the low
and mid 80s in low-elevated areas, and into the upper 70s and low
80s in the highest mountains.

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

Both pockets of more humid and pockets of drier air will reach
the region Monday and early Tuesday. Low saharan dust
concentrations will also move into the region on Monday,
resulting in hazy skies, and linger through at least Tuesday. In
the mid to upper levels, a high pressure will be present
throughout early Tuesday, before an trough moves in Tuesday and
into late Wednesday, increasing instability. Current model
guidance suggests that the trough will be well east by Thursday
and Friday. A series of surface highs and frontal lows will move
into the western to central Atlantic during the period, resulting
in east to east- southeast flow over the islands. This windflow
will steer more frequent patches of moisture into our area by
Tuesday onwards. Precipitable water (PWAT) values will be above
1.5 inches (above normal) with these moist patches. Moisture from
a frontal boundary north of the area could also reach us by
Friday. Most available moisture should by below 700 mb, during the
period. A variable weather pattern will include overnight and
early morning showers steered towards along eastern and southern
coastal sections of the islands with afternoon convection forecast
to focus across the central interior and north/northwest sectors
of Puerto Rico. With the approach of an upper-trough and
increasing moisture, and boost in this pattern is forecast by
midweek. 925 mb temperatures will be up to above normal values
during the period.

&&

.AVIATION...

(06z TAFS)

SHRA will move across the Caribbean waters, occasionally
reaching the USVI and TJSJ terminals. After 17Z, showers will also
develop across TJBQ. These showers could lead to brief periods of
reduced VIS and low ceilings, especially for TJBQ. Mountain
obscuration across the Cordillera Central is also expected from 17-
22Z. Winds will be from the ESE at 11-17 kts, with stronger gusts.

&&

.MARINE...

A surface trough with an axis centered just south of the region and
a broad surface high pressure over the eastern Atlantic will promote
up to moderate east-southeast winds. As the surface high pressure
builds over the Atlantic the local pressure gradient will tighten,
promoting a moderate to locally fresh east-southeast wind flow late
tonight and throughout the weekend. This could promote Small Craft
Should Exercise Caution criteria over some areas.

&&

.BEACH FORECAST...

A moderate risk of rip currents is forecast for today and tonight
for the north oriented beaches of Puerto Rico, from Aguadilla to
Rincon, northern Culebra and easternmost St. Croix. The risk for rip
currents is low elsewhere, however, life-threatening rip currents
often occur in the vicinity of groins, jetties, reefs, and piers.
The increasing winds expected for the weekend, will maintain up to a
moderate risk of rip currents for the islands.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
443 AM AST Sat Mar 1 2025

.SYNOPSIS...
A few passing showers are expected to move into the islands today,
with stronger showers developing in the northwestern corner of
Puerto Rico this afternoon. Some Saharan dust will filter in,
resulting in hazy skies. A trough will approach by midweek, with
heavy showers expected to develop across the interior and western
Puerto Rico each afternoon. Breezy conditions will promote choppy
seas this weekend, with a moderate rip of rip currents
anticipated.


&&

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

Current satellite derived precipitable water (PWAT) imagery show an
area of moisture over the USVI, Vieques, Culebra and eastern Puerto
Rico with values ranging from 1.45 to 1.50 inches. During the
overnight hours light to moderate showers steered, by east-southeast
winds, reached the aforementioned areas. Lows were in the upper 60s
(Puerto Rico) to mid 70s across coastal areas of the islands and in
the low 60s (locally cooler) at higher elevations of Puerto Rico.
The area of moisture will move over the islands during the day,
followed by a transition into drier pattern late in the afternoon
into tomorrow. This will be due to a mass of drier air that will
reach the islands and decrease PWAT values to around an inch.
Passing showers will move into the eastern region during the morning
hours. During the afternoon, convective shower activity will
concentrate over northwestern Puerto Rico, promoting a limited
excessive rainfall risk. Both pockets of more humid and pockets of
drier air will reach the region Sunday and Monday, passing advective
showers will still affect windward sectors of the islands during the
overnight to morning hours and afternoon convective showers will
affect W-NW PR each day. These showers will continue to be under E-
SE flow as a surface high centered over the eastern Atlantic will
continue to promote these increasing winds. In the mid to upper
levels, high pressure will be present throughout the short term
period, with most available moisture remaining below 700mb. Low
concentrations of saharan dust will filter into the region during
the weekend, promoting hazy skies. The east-southeasterly flow will
promote warmer than normal temperatures, particularly during the
afternoons. 925mb temperatures, will fluctuate between 1 to 2
standard deviations above the climatological mean. Highs will reach
the low to mid 80s at lower elevations of the islands, with some
areas reaching the upper 80s, and the upper 70s to low 80s at higher
elevations of Puerto Rico.


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

A mid to upper level trough will be approaching the islands by
Tuesday. A piece of the jet stream will also reach the islands,
while temperatures at 500 mb will cool down too. As a result,
instability aloft will be increased, enhancing the potential for
strong afternoon showers developing across the interior of Puerto
Rico. The areas that will receive the strongest winds will depend on
the dominant winds for each day. Easterly winds on Monday will
transport the showers toward the west, but winds will be more
southeasterly on Tuesday, so the northwest will likely experience
the strongest rains. The wind flow could slow down by Wednesday, so
the rain will linger across the interior, then being transported
southward by the northerly mid-level winds. While the main threat is
expected to be localized urban and small stream flooding, the
instability and diurnal heating could aid in the development of
lightning too, so thunderstorms were added to the forecast. By the
end of the week, yet another mid to upper level trough will approach
the region. The pattern will again favor the formation of showers
across the interior and western Puerto Rico each afternoon.

Each day of the workweek, the winds will also carry some showers
over eastern Puerto Rico and the Virgin Islands too. It is worth
mentioning that moisture content is not expected to be too abundant,
acting as a limiting factor for the intensity of the afternoon rain.
Also, traces of Saharan dust will linger into Tuesday, resulting in
hazy skies.


&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions expected. VCSH and possibly -SHRA will affect
TJSJ/TIST/TISX during the morning hours, gradually decreasing in
coverage. After 01/17Z, showers will also develop over NW PR and
affect TJBQ, possibly leading to brief periods of reduced VIS and
low ceilings, especially for TJBQ. ESE at 12-18 kts, with stronger
gusts, after 01/13Z.

&&

.MARINE...
A broad surface high pressure over the eastern Atlantic will promote
moderate to locally fresh winds this weekend. Small concentrations of
Saharan dust will result in hazy skies, but visibilities should
remain greater than 10 miles. Passing showers will continue across
the Caribbean and Atlantic waters.

&&

.BEACH FORECAST...
Increasing winds will maintain a moderate risk of life threatening
rip currents along the north, east, and southeast coast of Puerto
Rico, as well as for Vieques, Culebra, Saint Thomas, Saint John,
and Saint Croix.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST Sun Mar 2 2025

.SYNOPSIS...
Drier air has moved into the islands, with only isolated showers
expected today. An increase in showers is expected by midweek due
to the proximity of a trough, with the strongest activity across
the interior and northwestern Puerto Rico. A cold front is
expected to linger north of the area by the end of the week.

&&

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

Current satellite derived precipitable water (PWAT) imagery show a a
dry air mass over the islands with values ranging from 0.90 to 1.10
inches, 0.90 inches of PWAT is 2 standard deviations below normal
for this time of the year. During the overnight hours, light to
locally moderate showers steered by east-southeast winds affected
sectors of the islands. Radar estimated rainfall totals since
midnight indicate low accumulations over southeastern to eastern and
eastern interior Puerto Rico, Vieques, St. Croix, St. Thomas and St.
John. Stations reported minimum temperatures in the upper 60s to low
70s (some isolated mid 70s) at lower elevations of Puerto Rico, in
the mid 70s over Vieques, Culebra and the USVI, and in the upper 50s
to low 60s at higher elevations of Puerto Rico.

Low concentrations of Saharan dust will filter into the region
during the period, promoting hazy skies. Passing showers will move
into the eastern region during the morning hours as patchy fog over
some areas dissipates. During the afternoon, convective shower
activity will concentrate again over northwestern Puerto Rico,
however PWAT values today will be generally less than during the
rest of the period. During the overnight hours, a patch of moist
air will move in from the southeast, passing advective showers
will affect windward sectors of the islands. An area of moisture
(PWAT values at 1.5 or more) is expected to move south of the area
tomorrow as a trough develops north of the area and a cold front
approaches from the west. If the trough moves in during the
afternoon hours, the shifting steering flow from the east to
northeast can focus afternoon showers over west to southwest PR. A
dry air mass with PWAT values around an inch will affect the
islands tonight and into the overnight hours.

After this, a wetter and more unstable pattern is forecast for
Tuesday and into the long term period. A mid to upper level trough
will approach the islands by Tuesday. With an area of the jet stream
reaching the islands and 500 mb temperatures cooling down,
instability will increase and enhance the potential for stronger
afternoon convection, leading to a limited to elevated excessive
rainfall risk over interior to northwestern Puerto Rico. A limited
lightning risk was kept in the forecast, as diurnal heating and
the presence of saharan dust can also aid in thunderstorm
formation. A limiting factor is the moisture content as PWAT
values will be at around 1.5 inches.

Up to breezy E-SE flow will continue today due to a surface high
over the eastern Atlantic. This will promote warmer than normal
temperatures, particularly during the afternoons. Temperatures at
925mb will fluctuate between 1 to 2 standard deviations above the
climatological mean. Maximum temperatures will reach the low to
mid 80s, some areas in the upper 80s, at lower elevations of the
islands, and in the upper 70s to low 80s at higher elevations of
Puerto Rico.

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

A surface high pressure over the central Atlantic will maintain
the trade winds from the southeast at moderate speeds. At the mid
to upper levels, the axis of the trough will be positioned just to
the northeast of the islands. Even though, some instability will
remain over the islands, with mid-level temperatures a little
cooler than normal. A surface reflection of the trough will also
move over the islands, bringing some showers over the Virgin
Islands and eastern Puerto Rico. However, the strongest showers
are expected for the interior and northwest of Puerto Rico, where
there is also a chance of lightning.

By the end of the week, the winds will gain a southerly component
due to a cold front that exits the eastern coast of the United
States. As the front approaches, the winds will become light and
variable. The moisture and showers associated with this front will
likely reach the islands as fragmented patches of clouds, so a
significant increase in showers is not expected. However, with
light winds, any episode of rain that develops will likely linger,
resulting in an elevated risk of urban and small stream flooding.
Additionally, with these southerly winds on Thursday and Friday,
it is likely that temperatures will feel above normal, with highs
in the upper 80s for coastal areas.

The forecast is a little more uncertain by late Saturday and
Sunday. There are discrepancies on how much moisture will reach
the islands by then. For now, a wetter solution is shown, with a
40-50% chance of showers increasing across the Atlantic waters,
the northern and eastern municipalities of Puerto Rico, and also
for the Virgin Islands.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions expected. VCSH will affect TJSJ/TJPS/TIST/TISX
during the morning hours. After 02/17Z, showers will also develop
over NW PR and affect TJBQ, possibly leading to brief periods of
reduced VIS and low ceilings. ESE winds at 10-15 kts, with stronger
gusts, after 02/13Z. THe presence of Saharan Dust will promote some
HZ, but visibilities will be P6SM.

&&

.MARINE...
A broad surface high pressure over the eastern Atlantic will promote
moderate to locally fresh southeasterly winds through tomorrow.
Moderate east to northeast trades return on Tuesday. A cold front
will move across the western Atlantic, approaching the islands from
the west Monday and Tuesday. Additionally, a surface trough will
bring passing showers across the local waters.

&&

.BEACH FORECAST...
The rip current risk will be moderate for the north, east,
southeast coast of Puerto Rico, and also for Vieques, Culebra,
Saint Thomas, Saint John, and Saint Croix. This risk is expected
to continue for the next several days.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST Mon Mar 3 2025

.SYNOPSIS...

A patch of moisture will promote light to moderate showers under
southeasterly flow this morning, afternoon showers mainly over
northwestern PR are forecast. The arrival of a surface trough on
Tuesday will increase the potential for showers across the
islands. Then, an upper- level trough will increase instability,
and interacting with the induced pre- frontal trough will result
in scattered to numerous showers and even thunderstorms through at
least Wednesday.

&&

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

Lots of clouds were observed across the Virgin Islands during the
night hours, while skies were mostly clear to partly cloudy across
Puerto Rico. Early in the night hours, some showers moved over
eastern Puerto Rico, and new showers developed early in the morning
across the Caribbean waters. Temperatures cooled down to the low and
mid-70s for coastal area, and the low and mid-60s for the
mountains.

Wetter conditions are anticipated this week for the islands. First,
winds will be modulated by a surface high pressure over the eastern
Atlantic and a mid to upper level trough (with its associated cold
front) to the northwest of the region. These features are weakening
the pressure gradient, causing lighter winds, out of the southeast
at 10 knots or less. As the trough approaches, conditions aloft will
become more favorable for shower production too. A patch of
moisture is moving into the islands today, bringing near normal
precipitable water content (1.4-1.6 inches). This layer of
moisture stretches into the mid-levels (to around 650 mb).
Considering all these factors, as well as diurnal heating and
local effects, it is likely that showers will fire up this
afternoon across the interior and northwestern Puerto Rico,
potentially lingering into the night hours (50-80% chance). The
risk of urban and small stream flooding will be elevated, with
water surges and potential mudslides as well. Conditions are not
too favorable for thunderstorms yet, as 500 mb temperatures are
still warmer than normal, but isolated lightning cannot be ruled
out.

Then, a surface trough will approach early on Tuesday, increasing
the frequency of showers for the Virgin Islands, Vieques, and
Culebra. Again, afternoon convection is anticipated for the
interior, west and northwest Puerto Rico in the afternoon hours. One
key difference for Tuesday is that the mid level temperatures will
cool down, so it will be more likely to see lightning with the
stronger showers. Moving into Wednesday, instability persist, but
there is uncertainty on where the afternoon showers will form.
First, the low level winds will contribute in the initiation of
convection in the interior, as usual, but then the movement of this
activity will depend on how much these showers grow vertically. If
the showers are shallow enough, a north-northwesterly progression is
expected, but if the showers manage to be steered by the mid-level
winds, then they will likely move southward. The forecast is a
compromise of both solutions, showing a widespread area of 30-50% of
probability of precipitation across most of Puerto Rico, but with
the higher chances (50-70%) for the northwest corner.

Also, the aerosol models show lingering Saharan dust today,
gradually clearing out by mid-week. Low concentration of Saharan
dust may increase the frequency of lightning within the
thunderstorms. And finally, temperatures...it will be warmer than
normal for areas that do not experience as much rain, since 925-mb
temperatures are one to two standard deviation higher than normal.
Highs can be expected in the mid to upper 80s for coastal areas, and
cooler in the mountain.

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

By Thursday, the upper level trough will be east-northeast of the
islands and will continue to move away from the islands. To start
the long term period, at surface level, a high pressure system will
be over the central Atlantic, while a frontal low moves into the
eastern Atlantic. Current model guidance suggests this and other
frontal lows moving into the Atlantic during the period on Thursday,
Friday and Monday before high pressure builds and dominates late
Monday. This will cause changes in the steering flow during the
period, east-southeast on Thursday, east-southeast to east-northeast
on Friday (due to an approaching cold front), east-northeast on
Saturday and then gradually veering during the weekend to east-
southeast late Sunday into Monday. The period will start off with
precipitable water (PWAT) values around 1.5 inches, mainly
maintained by an approaching frontal boundary with the lingering
traces of saharan dust dissipating. Model discrepancies are present
regarding moisture during the weekend, with one more inclined to
patches of moisture reaching the island during that time. This
includes small pockets of moisture with PWAT values around 1.4 to
1.5 inches reaching the islands. Available moisture should remain
below 750 mb Thursday through Saturday, and below 850 mb by Sunday
and Monday. As the front approaches the region to end the workweek,
winds will decrease to become light and variable, this will result
in slow and lingering showers, elevating the excessive rainfall risk.
During the period, the diurnal pattern will vary depending on the
steering flow. This includes, overnight and early morning showers
steered towards windward sectors of the islands while afternoon
convection will focus over the interior to either northwestern
(under southeast flow) or southwestern (under northeast flow) PR
depending on the steering flow that day. 925 mb temperatures will be
up to above normal values during the period, especially on days with
east-southeast to southeast flow.

&&

.AVIATION...

(06Z TAFS)

Increasing SHRA expected today, especially after 17Z for the
northwestern quadrant of PR. Periods of reduces VIS and low
ceilings expected for TJBQ at least until 22Z. Mountain
obscuration is also expected for the western Cordillera Central.
Winds will be from the SE at 8-12 kts, with stronger gusts.

&&

.MARINE...

A frontal boundary approaching from the western Atlantic will slowly
loosen the pressure gradient associated with the broad surface high
pressure extending from the eastern to central Atlantic. This will
promote east-southeast winds today and tonight. Winds will back
to become east to northeast through tomorrow as an induced surface
trough associated with the frontal boundary moves in. This will
also increase the risk of showers and even thunderstorms across
the regional waters late tonight through Wednesday.

&&

.BEACH FORECAST...

For today, a moderate rip of rip currents will be present at the
easternmost beaches of St. Croix, life-threatening rip currents are
possible in the surf zone. Other coastal areas across the islands
will have a low risk of rip currents today, however, life-
threatening rip currents often occur in the vicinity of groins,
jetties, reefs, and piers. During the rest of the workweek, a
moderate risk of rip currents will be in effect for the north-facing
beaches of Puerto Rico, Culebra and the USVI at times.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
459 AM AST Tue Mar 4 2025

.SYNOPSIS...

Unstable weather conditions will persist today through the end of
the workweek as a trough crosses the forecast area. Expect shower
and isolated thunderstorm activity during this period. More stable
weather condtions expected this weekend. A northwesterly swell
will reach the Atlantic waters this weekend resulting in potential
hazardous seas and beach conditions.

&&

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

The axis of a surface trough was located just east of the Virgin
Islands early this morning. This trough maintains the winds from the
northeast, bringing a few showers across the Virgin Islands, and the
north and east coast of Puerto Rico. Other than that, lots of clouds
lingered across southwestern Puerto Rico, while variably cloudy
skies were observed elsewhere.

A mid to upper level trough is located just to the northwest of the
area. Instability aloft is expected to increase, with mid-level
temperatures cooling down today and tomorrow. This system maintains
the trade winds weak, generally coming out of the southeast at 7 to
9 kts. The surface trough will increase moisture, from the surface
to nearly 700 mb. In fact, precipitable water values are expected to
be above normal through Wednesday, around 1.6-1.8 inches. This will
translate into another active afternoon, with widespread showers,
and even thunderstorms developing. For eastern Puerto Rico and the
Virgin Islands, the frequency of showers will increase this morning
and early in the afternoon hours. However, the strongest activity is
anticipated again for the interior and western Puerto Rico. Since
the axis of the trough will be likely crossing the area early this
afternoon, it is not clear whether the winds will shift on time to
move the showers into the northwestern corner of Puerto Rico or if
the main focus will be the southwest, like yesterday. Due to this
uncertainty, an elevated flooding risk is shown for all the western
municipalities of Puerto Rico, as these rains could result in urban
and small stream flooding, water surges, and isolated mudslides.

A similar story is expected for tomorrow, but by Thursday, the mid
to upper level trough will departs and a ridge will build behind.
Conditions aloft will no longer favor the formation of
thunderstorms, but enough surface moisture will drag additional
showers across eastern Puerto Rico and the Virgin Islands, while
another round of showers is anticipated for the west in the
afternoon hours.

Temperatures will continue to cool down in the overnight hours, with
values in the low and mid 60s for the mountain, and the mid 70s for
coastal areas. However, it will warm up during the daytime. Right
now, 925 mb temperatures are expected to be one to two standard
deviation above the climatological value, meaning that highs will
reach the mid to upper 80s in areas without any significant
afternoon rain.


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

Friday will be a transition day as marginal instability from
lingering troughiness aloft, combined with sufficient low-level
moisture, persists. At the surface, a frontal boundary will continue
approaching from the northwest. Ahead of it, a shearline with an
associated col region will move across the forecast area, causing
wind speeds to plummet.

During the morning hours, expect scattered showers to develop over
regional waters, occasionally drifting inland across eastern Puerto
Rico and the smaller islands. By the afternoon, diurnal heating,
combined with lingering moisture and instability, will promote
convective development. Weak steering winds will enhance sea breeze
convergence and orographically driven convection, potentially
resulting in isolated thunderstorms. Additionally, slow-moving
showers will elevate the risk of localized flooding, particularly
along the central mountain range of Puerto Rico, where limited to
moderate flooding is possible.

For the remainder of the long-term period, moisture levels will
remain near to below normal, while upper-level dynamics will remain
mostly stable. This stability is supported by increasing 250 mb
height fields and slightly warmer-than-usual 500 mb temperatures as
a mid-level ridge builds over the northeastern Caribbean. Shower
activity will follow a seasonal weather pattern, with passing
showers moving over windward coastal areas during the night and
morning hours. By the afternoon, localized shallow convection will
develop across western Puerto Rico. However, given the stable
conditions and limited moisture, no significant flooding risk is
anticipated.


&&

.AVIATION...
(06Z TAFs)

Isolated to scattered SHRA expected this morning for the local
waters, occasionally moving over the Virgin Islands and TJSJ
terminals. After 17Z, SHRA and TSRA are expected for the Cordillera
Central, potentially reaching TJSJ, TJBQ and TJPS. Some periods
of reduced VIS and low ceilings are anticipated. Winds will pick
up after 13-14Z, coming out of the ENE at the SFC at 9-11 kts,
then gaining a SE component after 15Z from 6-12 kft.


&&

.MARINE...

A frontal boundary approaching from the western Atlantic will slowly
loosen the pressure gradient associated with the broad surface high
pressure extending from the eastern to central Atlantic. This will
result in winds becoming east to northeast through tomorrow as an
induced surface trough associated with the frontal boundary moves in.
This will also increase the risk of showers and even thunderstorms
across the regional waters today through Wednesday. A long-period
northwesterly swell will reach the regional waters this weekend,
likely resulting in hazardous seas across the Atlantic waters and
northern portions of the local passages.

&&

.BEACH FORECAST...

Life-threatening rip current conditions are possible today along
beaches in northwestern and north-central Puerto Rico, as well as
St. Croix. By late tonight and into tomorrow, a weak northwesterly
swell will reach the Atlantic waters, increasing breaking wave
heights. This will, in turn, possibly elevate the risk of rip
currents along northern exposed beaches.

Residents and visitors in these areas should heed warnings and stay
informed through updates from local authorities.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
Issued by National Weather Service Miami FL
414 AM AST Wed Mar 5 2025

.SYNOPSIS...

An unstable weather pattern is expected today through the end of the workweek,
as instability and moisture persist over the region. Morning conditions
will be variable, followed by afternoon convection developing along
the mountainsides and in the northwestern quadrant. There is an
elevated threat of urban flooding, particularly in areas that have
experienced recent rainfall.

&&

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

As expected, the mid-to upper-level trough persisted over the local area,
although the most active region remained well north of the northeastern
Caribbean. Still, the land breeze combined with sufficient low-level
moisture and instability aloft generated a line of heavy showers
just offshore of northern coastal Puerto Rico. These showers persisted
for most of the night, occasionally brushing portions of the coast.
Marine Weather Statements were issued throughout the night for this
area. Similar activity is expected to continue over the next few hours,
with some areas along northern coastal Puerto Rico likely to see an
increase in showers as the land breeze subsides and some of these
showers move inland.


The strongest phase of the trough will occur today, promoting low 250 mb
height fields and cool 500 mb temperatures. However, as mentioned earlier,
its most active area will remain north of the Caribbean. At low levels,
an induced surface trough will continue moving across the forecast
area today, maintaining above-normal moisture content. This pattern,
combined with diurnal heating and sea breeze convergence, will
lead to another active afternoon. Showers and isolated thunderstorms
are expected to develop over interior Puerto Rico by early afternoon,
propagating outward toward coastal areas through the evening.
Later tonight, shower activity is expected to develop over regional
waters, with some showers potentially affecting coastal areas of
Puerto Rico and the U.S. Virgin Islands, particularly St. Thomas.
However, significant rainfall accumulations are not anticipated
during this period.

A similar weather pattern is expected on Thursday and Friday, with
dynamics aloft gradually becoming less unstable as the trough
moves eastward and weakens, though some marginal instability will
linger through Friday. Meanwhile, moisture content will slightly
decrease to near normal levels. However, a frontal boundary
northwest of Puerto Rico will approach the northeastern Caribbean.
As it nears, winds will shift more southeasterly on Thursday and
southerly by Friday, while wind speeds will plummet as a col
settles just north of Puerto Rico. Although above-normal moisture
and instability are not expected for the remainder of the short-
term forecast, sufficient moisture will still combine with surface
heating during the afternoon hours. Additionally, weak steering
winds will prolong the residence time of showers and any thunderstorms
that develop, enhancing rainfall accumulations. As a result, expect
a limited to elevated flooding risk each afternoon, mostly across
interior Puerto Rico, potentially leading to urban and small-stream
flooding. Quick river rises and water surges are also anticipated
in some rivers.

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

Mid- to upper-level atmospheric stability will remain in place from
Saturday through Wednesday as a mid-level ridge builds over the western
Atlantic, extending into the Caribbean. This feature will support
warmer-than-normal 500 mb temperatures, suppressing deep convective
development across the region.

A broad surface pressure system will dominate the region through the
weekend, maintaining a northeasterly wind flow until Sunday morning.
Under this wind flow, mostly shallow patches of moisture with
precipitable water (PWAT) values below climatological normals
will persist. However, surface heating and local effects will
contribute to shower development shifting toward the southwestern
quadrant of Puerto Rico. By late Sunday, winds will gradually
shift from the east-southeast as a surface high pressure moves
westward into the central Atlantic. According to the model global
guidance, Precipitable water values would remain near or just
below normal. As a result, shower activity will follow a seasonal
pattern, with isolated to scattered showers moving across windward
coastal areas during the night and early morning hours, followed
by localized shallow convection developing across western and some
interior sections of Puerto Rico in the afternoons. Given the
stable conditions and limited moisture availability, significant
rainfall accumulations or widespread flooding concerns are not
anticipated.

By early next workweek, drier air will gradually filter into the
region. Tuesday and Wednesday are expected to be the driest days
under the influence of the mid-level ridge and limited moisture
availability. Overall, a quiet weather pattern is expected through
the long-term period, with limited shower activity and stable
atmospheric conditions dominating the local forecast.

&&

.AVIATION...
(06Z TAFs)

VFR conds will prevail except for MVFR in passing SHRA, particularly
for TJSJ taf site. Expect areas of +SHRA/TSRA to bring MVFR/IFR
conds to wrn and interior PR with mtn obscurations aft 05/17Z,
SHRA will diminish aft 05/23Z, but sct SHRA will cont ovr ern PR.
Sfc winds E 10-15 kts with hir gusts in sea breezes. Winds bcmg
land breezes at less than 10 kts aft 06/00Z.

&&

.MARINE...

A frontal boundary approaching from the western Atlantic will
gradually weaken the pressure gradient associated with the broad
surface high pressure extending from the eastern to central
Atlantic, leaving mostly light to moderate easterly winds. An
upper-level trough and the associated instability will continue to
result in showers and some isolated thunderstorms over the
regional waters throughout the day. Additionally, a long-period
northwesterly swell is expected to arrive this weekend, likely
creating hazardous marine conditions across the Atlantic waters
and northern local passages.

&&

.BEACH FORECAST...

A moderate risk of rip currents will persist along the northern
coastal areas of Puerto Rico due to a brief and weak northerly
swell. Breaking waves are expected to reach up to 5 feet along
northern areas, with lower heights across the rest of the coastal
sections of the islands.

Coastal conditions are expected to deteriorate over the weekend
as another northerly swell arrives, increasing breaking waves
along the northern sections of the islands.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
436 AM AST Fri Mar 7 2025

.SYNOPSIS...There is an elevated risk for urban and small stream
flooding this afternoon as showers with isolated thunderstorms
develop across central and south Puerto Rico. A drier weather
pattern is expected to prevail during the weekend into early the
next workweek. Dangerous surf conditions are anticipated Saturday
and Sunday as a long period northwesterly swell spreads mainly
across the Atlantic waters.


&&

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

Satellite-derived data showed above-normal PWAT values, mainly over
and to the south/east of the forecast area, throughout the night.
The land breeze and generally weak winds promoted a convergence zone
between eastern/southeastern Puerto Rico and Vieques/Culebra,
leading to the development of a southwest-to-northeast oriented line
of strong showers that remained mostly stationary for an extended
period. Due to the islands' land breezes, the line of showers stayed
mostly over the waters, with some occasionally brushing coastal
municipalities in southeastern Puerto Rico. During the morning
hours, expect a few showers over the waters that could move onshore
at times, but with minimal rainfall accumulations.

A southwest-to-northeast oriented frontal boundary currently
northwest of Haiti will continue to approach the area today. This
will push a col region, currently over the Dominican Republic, over
the forecast area. As a result, light steering winds will persist.
Wind direction will be variable today, shifting from southerly in
the morning to more northerly in the afternoon as the col region
moves eastward. Dynamics aloft will be marginal, with mid-level
drier air persisting, which will inhibit deep convection for the
most part. However, sufficient low-level moisture, combined with
surface heating and sea breeze convergence enhanced by orographic
effects, will promote shower activity. Showers will first develop
over the Cordillera Central and later move southward due to the
northerly steering wind flow. The very light winds will cause these
showers to move slowly, enhancing rainfall accumulations.

Hi-Res models indicate a limited to elevated flooding threat across
these areas. However, some of these models have been slightly
bullish with rainfall accumulations over the past 24 hours.
Nevertheless, it is important to continue monitoring weather
conditions this afternoon, as moderate to locally heavy rainfall,
with isolated amounts exceeding an inch, could lead to urban and
small-stream flooding.

For this weekend, a more northeasterly flow on Saturday, shifting to
an easterly flow on Sunday, will steer drier air into the region.
This will combine with ridge building at mid to upper levels,
leading to more stable weather conditions. However, passing showers
can still be expected during the morning hours, with isolated to
scattered showers developing in the afternoon. The risk of flooding
will be minimal to none.

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

The ridge pattern aloft is expected to weaken early in the
forecast cycle as a trough pattern develops north of the area.
The trough aloft and associated surface boundary will enhance
moisture advection by the end of the workweek, with the latest
guidance suggesting a sharp increase in precipitable water Friday
into Saturday. At lower levels, a light east to east southeast
wind flow will prevail throughout the week, becoming northeasterly
Saturday into Sunday as the aforementioned frontal boundary
approaches the local islands. Under this evolving pattern, limited
shower activity is expected across the local islands Monday and
Tuesday being Tuesday the driest day. Then, an increase in
afternoon showers and thunderstorms is expected across central and
western Puerto Rico due to moisture advection, diurnal heating,
and sea breeze convergence. Therefore, a limited risk for urban
and small stream flooding is expected on Wednesday and Thursday,
becoming elevated on Friday and Saturday.

&&

.AVIATION...

06Z TAFs)

Mainly VFR conditions will prevail across most terminals. Afternoon
SHRA could cause mtn top obsc and MVFR/IFR at TJPS between 07/17-
22Z. Calm to light and variable winds becoming more northerly with
sea breeze variations at 8-11 mph aft 07/14Z. Winds become light and
variable aft 07/22Z.

&&

.MARINE...

Deteriorating marine conditions are expected mainly across the
Atlantic waters as a long period northwesterly swell spreads
across the local waters late tonight into Saturday. As a result,
building seas up to 7 feet, with occasional seas up to 9 feet,
are expected tonight into Saturday with Small Craft Advisories
for AMZ711 and AMZ712. Marine conditions are expected to improve
Monday onwards.

&&

.BEACH FORECAST...

Dangerous surf conditions are anticipated for the weekend as a
long period northwesterly swell spread mainly across the Atlantic
waters. Therefore, there is a High Risk of Rip Currents from
northwest Puerto Rico eastward to Luquillo and Fajardo. Life-
threatening rip currents often occur in the vicinity of groins,
jetties, reefs, and piers.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
449 AM AST Sat Mar 8 2025

.SYNOPSIS...

Expect a mix of sunshine and scattered showers throughout the
morning, mainly across northern and eastern Puerto Rico and the
smaller islands, followed by afternoon showers over southwestern
Puerto Rico. A long-period northerly swell will create hazardous
seas and coastal conditions today. High Rip Current Statements,
Small Craft Advisories, and High Surf Advisories are in effect.

&&

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

Overnight, calm weather prevailed across Puerto Rico and the U.S.
Virgin Islands, with mostly clear skies and isolated showers over
northwestern Puerto Rico, Culebra, Vieques, and Saint Thomas.
Coastal and urban areas saw temperatures in the 70s, while
mountainous and rural areas remained in the 60s. Winds were light
from the northeast.

Today, winds will continue from the northeast, shifting easterly on
Sunday. Model guidance indicates drier air and a mid-to-upper-level
ridge, promoting stable weather with reduced rainfall through the
weekend. However, passing morning showers and isolated to scattered
afternoon showers are still expected. The risk of flooding remains
low, particularly in the afternoons.

Early next week, the ridge aloft will weaken as a trough develops
north of the region.

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

The long-term forecast begins with generally fair weather as ridging
aloft dominates the area. Well-below-normal moisture content will
prevail from Tuesday through early Wednesday, with precipitable
water and 500 mb relative humidity values likely dropping below 1.0
inch and 5%, respectively. This will limit shower activity across
the islands, with mostly clear and sunny skies prevailing.

By midweek, some weakening of the mid-level ridge is expected in
response to a deep-layered trough moving north of the forecast area.
Additionally, there is potential for a jet around 200 mb to impact
the region, which could enhance ventilation aloft. A frontal
boundary associated with the trough will approach the region from
the northwest by Thursday, stalling over the northern Caribbean
through Saturday. Winds will weaken and become more variable as a
shear line and col cross the islands on Wednesday. Afterward, winds
will remain mostly from the northeast on Thursday before shifting
more from the southeast on Friday, eventually becoming variable as a
surface-induced low develops northwest of Puerto Rico and moves
eastward through the period.

Meanwhile, moisture will surge beginning Thursday due to convergence
over the area, with patches of moisture pushing in, slowing down,
and interacting with both the frontal boundary and the surface-
induced low. Moisture content, which was previously confined below
750 mb, will extend up to the 500 mb layer. The combination of
increased instability, above-normal moisture levels, and low-level
convergence will result in an uptick in shower and thunderstorm
activity, particularly from Thursday through the end of the forecast
period. As a result, a limited to elevated flooding threat is
expected to return by Thursday of next week, increasing the
potential for urban and small-stream flooding. Isolated flash
flooding and mudslides cannot be ruled out.

Forecast confidence is near normal. Sources of uncertainty include
the positioning of the trough and its associated frontal boundary
relative to the islands, as well as the timing and magnitude of
moisture levels.


&&

.AVIATION...
(06Z TAFs)

VFR conditions will mainly prevail across all TAF sites. VCSH will
affect TJSJ, TISX, and TIST after 08/13Z, and SHRA could affect TJPS
after 08/17Z. Winds will remain from the NE at around 5 to 13 kt
with sea breeze variations.


&&

.MARINE...

A northwesterly swell is beginning to reach the offshore Atlantic
waters, and will deteriorate marine conditions as it spreads across
the local waters today. Small Craft Advisories are in effect through
late tonight for the offshore and nearshore Atlantic waters.
Winds will be east-northeasterly to east during the weekend, as a
cold front north of the local area dissipates.


&&

.BEACH FORECAST...

Model guidance indicates that a long-period northwesterly swell will
reach the Atlantic waters from the morning through the afternoon.
Based on the expected magnitude of this swell, large breaking waves
of 8 to 10 feet could impact coastal areas from Rincon and Aguada,
along the northern coastline of Puerto Rico through Fajardo, as well
as Culebra and northern U.S. Virgin Islands.

This will result in minor beach erosion and hazardous swimming
conditions across northern Puerto Rico, with life-threatening rip
currents affecting the rest of the impacted beaches, including
Culebra and the northern U.S. Virgin Islands. As a result, High Surf
Advisories and Rip Current Statements are in effect. 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
510 AM AST Sun Mar 9 2025

.SYNOPSIS...

Similar weather conditions to yesterday can be expected today, with
a mix of sunshine and scattered showers throughout the morning,
mainly across northern and eastern Puerto Rico and the smaller
islands, followed by afternoon showers over interior and
southwestern Puerto Rico. A wet and unstable weather pattern is
expected by the end of the workweek. Meanwhile, a subsiding long-
period northerly swell will continue to promote hazardous beach
conditions today.


&&

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

Tonight, showers filtered across eastern Puerto Rico, Culebra, and
Vieques, bringing periods of light to moderate rainfall. This
rainfall activity left minimal accumulations, with no significant
flooding or disruptions reported. Skies remained mostly cloudy in
affected areas, while the western half experienced clear conditions.
Temperature-wise, coastal and urban areas saw in the 70s, while
mountainous and rural regions remained in the 60s. Light
northeasterly winds persisted throughout the night. Patchy fog was
seen along the Cordillera Central, especially where the skies were
clear. Looking ahead, isolated showers may continue into the early
morning hours, with a gradual improvement in weather conditions as
drier air filters across Puerto Rico and the U.S. Virgin Islands.

As the frontal boundary continues to dissipate north of the region,
winds will gradually shift easterly today. The latest model guidance
suggests that dry air, along with a mid-to-upper-level ridge, will
build aloft, promoting a stable weather pattern. However, occasional
patches of moisture will still move in with the trade winds,
bringing passing clouds and brief showers to windward areas through
the beginning of the workweek. In the afternoons, local effects will
drive convection, leading to showers developing over the mountains
and western Puerto Rico, as well as downwind of the islands.

By late Monday into Tuesday, a multilevel trough is expected to
develop north of the region. Current model projections indicate that
precipitable water values will range from near-normal to below-
normal for this time of year, suggesting limited moisture
availability.

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

The long-term forecast remains on track as model guidance continues
to suggest an unstable weather pattern developing by the end of the
workweek into the weekend. Wednesday will start fairly calm, with
well-below-normal moisture, as ridging aloft dominates the forecast
area. However, by Thursday, the weather pattern will begin to change
as the mid-level ridge erodes and is pushed eastward by a series of
back-to-back mid-to-upper-level troughs crossing the northern
Caribbean.

This pattern will promote cold air advection at 500 mb, dropping
temperatures to between -7C and -9C. Additionally, 250 mb heights
and 1000-500 mb thickness values will drop to near-normal levels,
accompanied by strong cyclonic vorticity advection in the vicinity.
This instability will combine with above-normal moisture content as
a frontal boundary, associated with upper-level dynamics, stalls
over the islands, leading to low-level convergence. Considering the
09/00Z model run cycle, the median quartile of precipitable water
values in the region, based on ensemble data from the ECMWF, GFS,
and CMC global models, ranges between 1.5 and 1.9 inches by
Friday. This supports high forecast confidence in near to well-
above-normal moisture content across the region.

Therefore, expect a gradual increase in shower and thunderstorm
activity across the northeastern Caribbean. On Thursday, the
weather pattern will follow a more seasonal trend, with showers
developing over windward coastal areas of the islands in the
morning and later across interior and southwestern portions of
Puerto Rico in the afternoon, as diurnal heating and sea breeze
convergence combine with instability aloft.

The areal coverage of showers and thunderstorms will begin to
increase from Thursday night through the weekend as instability and
moisture content continue to rise. A limited to elevated flooding
threat will prevail, leading to urban and small stream flooding, as
well as potential landslides and rockfalls in vulnerable and steep
terrain.


&&

.AVIATION...
(06Z TAFs)

VFR conditions will prevail across all TAF sites. VCSH will affect
TJPS and TJBQ after 09/17Z. Winds will prevail from the NE and
gradually become E at around 4 to 14 kt with sea breeze variations.

&&

.MARINE...

A frontal boundary will continue to dissipate near the region today,
inducing east-northeasterly to east winds. Another surface high
pressure will build north to the northeast across the Central
Atlantic by Tuesday, while a surface low and associated frontal
boundary moves across the western Atlantic. This will bring shower
and thunderstorm activity across the region by the end of the
workweek. Another long-period northerly swell will spread across the
Atlantic waters and local passages by next weekend, resulting in
hazardous seas once again.

&&

.BEACH FORECAST...

Nearshore buoy data continue to indicate estimated breaking waves of
6-8 feet. Therefore, the High Rip Current Risk has been extended
through noon today for all beaches from Rincon and Aguada, along
the northern coastline of Puerto Rico through Fajardo, as well as
Culebra and the northern U.S. Virgin Islands. We will continue to
monitor beach conditions as the northerly swell gradually subsides
and extend the rip current risk if deemed necessary.

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

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
347 AM AST Mon Mar 10 2025

.SYNOPSIS...

In general, fair weather conditions and warmer temperatures will
persist through at least midweek under ESE winds. However, a wet
and unstable weather pattern is forecast by the end of the
workweek into the weekend due to the arrival of upper-level
troughs and a frontal system. A long-period northerly swell will
spread across the Atlantic waters and local passages next weekend,
resulting in hazardous marine and coastal conditions.


&&

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

Overnight, mostly cloudy skies with showers affected northern and
western Puerto Rico. However, rainfall accumulations were minimal,
with no significant flooding or disruptions. Temperatures remained
in the 70s across coastal and urban areas, while mountainous and
rural regions stayed in the 60s. Winds were light and variable from
the east, and patchy fog developed along the Cordillera Central,
particularly in areas where skies cleared.

Today and Tuesday, generally dry and stable conditions will prevail
across Puerto Rico and the U.S. Virgin Islands as a drier air mass
moves in and a mid-to-upper-level ridge holds. However, despite this
stability, east-southeasterly winds will continue to bring pockets
of moisture, leading to occasional cloud cover and passing showers
in windward areas. As in previous days, late afternoon convection
driven by sea breeze and local effects may develop over the
mountains, west-northwestern Puerto Rico, and downwind of the Virgin
Islands.

By Tuesday night into Wednesday, the ridge aloft will weaken as an
upper-level trough approaches the Northeast Caribbean from the west.
Model guidance indicates that the moisture content will remain below
850 mb, suggesting that any showers that do form will be shallow
with limited vertical development (low chance for it to have
opportunity for strong development) due to insufficient
instability.

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

Back-to-back mid-to upper-level troughs will move across the
northeastern Caribbean on Thursday and Friday. This transition
will promote cold air advection at 500 mb, causing temperatures to
drop to around minus 7 degrees Celsius aloft. Additionally,
heights at 250 mb and thickness values between 1000-500 mb will
return to near-normal levels. This instability, combined with
normal to above-normal precipitable water (PWAT) content
(1.40-1.60 inches) from a stalled frontal boundary just north of
the area, will enhance the development of afternoon convection
over the interior and southwestern sections of Puerto Rico each
day.

Thereafter, a building surface high pressure over the western
Atlantic will promote moderate to fresh (15-20 knots)
northeasterly winds across the local area through the weekend,
pushing the remnants of the front over the islands. This will
further increase PWAT values to nearly 1.80 inches by Saturday
afternoon. Consequently, there will be a limited to elevated
excessive rainfall threat, leading to urban and small stream
flooding and potential landslides and rockfalls in vulnerable and
steep terrain, mainly over portions of the Cordillera and
west/southwest PR. Across the U.S. Virgin Islands, the highest
probability of precipitation(40%-60%) is from late Friday through
the weekend as shower activity increases due to the expected
frontal passage.

At the upper levels, a ridge building from the western Caribbean
late in the forecast cycle is expected to promote drier air and
more stable conditions. Therefore, fair weather conditions are
expected across the islands on Monday.


&&

.AVIATION...

(06Z TAFs)

VFR conditions will prevail across all TAF sites. VCSH will affect
TJPS and TJBQ after 10/18Z. Winds will prevail from the E-SE around
4 to 14 kt with sea breeze variations.


&&

.MARINE...

A surface high pressure will build and migrate toward the central
Atlantic early this week, while a surface low and associated frontal
boundary moves across the western Atlantic. This will shift the winds
from the east-southeast through Wednesday. By the end of the week,
the potential for showers across the local waters will increase as
the front moves closer to the area, and winds turn from the east to
northeast. Another long-period northerly swell will spread across
the Atlantic waters and local passages next weekend, resulting in
hazardous seas once again.


&&

.BEACH FORECAST...

Lingering north-northeast swell continues to spread across the
Atlantic waters. Offshore buoy 41043 about 170 NM NNE of San Juan
indicated swell heights between 4.9-5.6 feet at 11-12 seconds
after midnight. Swell decay will cause seas to range between 3-5
feet at 11-13 seconds at times across the nearshore Atlantic waters
of the islands through the rest of the morning hours. Therefore, a
moderate to high risk of rip currents will continue today, and a
High Rip Current Risk was reissued for the northern coast of
Puerto Rico.

Another northerly swell will spread across the Atlantic waters on
Thursday and Friday, increasing the potential for life-threatening
rip currents once again. A larger swell is expected later during
the weekend.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
402 AM AST Tue Mar 11 2025

.SYNOPSIS...

Fair weather conditions and warmer temperatures will persist
through Wednesday under southeasterly winds. A wet and unstable
weather pattern is forecast by the end of the workweek into the
weekend due to the arrival of upper-level troughs and a frontal
system. A long-period northerly swell will spread across the
Atlantic waters and local passages next weekend, resulting in
hazardous seas and life-threatening rip currents.


&&

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

A calm night prevailed across Puerto Rico and the U.S. Virgin
Islands, with patchy fog developing along the Cordillera Central,
especially in areas where skies cleared. Similar to the previous
night, temperatures remained in the 70s across coastal and urban
areas, while mountainous and rural regions cooled to the 60s.
Winds were light and variable.

Today is expected to be the driest and most stable day of the
short-term period as a mid-to-upper-level ridge remains in place,
keeping most humidity below 700 mb. However, despite this
stability, east-southeasterly winds will continue to bring pockets
of moisture, leading to passing showers. As in previous days,
late afternoon convection driven by sea breezes and local effects
may develop over west-northwestern Puerto Rico.

By Wednesday, the ridge aloft will begin to weaken as an upper-
level trough approaches the Northeast Caribbean from the west,
gradually increasing atmospheric instability.

On Thursday, winds will become variable, gradually shifting from
the south-southwest before transitioning to a north-northeasterly
flow. Instability will further increase as mid-level temperatures
will drop to around -7 degrees Celsius while moisture levels will
extend up to 500 mb. This suggests that any showers that develop
will have a higher potential for vertical growth, increasing the
likelihood of stronger convection. Additionally, a frontal
boundary will stall just north of the region, enhancing afternoon
convection over Puerto Rico’s interior and southwestern areas.
Given these conditions, isolated thunderstorms are currently
forecast, particularly on Thursday.

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

A short-wave trough will move quickly just north of the area on
Friday, and the 500 MB temperatures are now expected to warm by a
few degrees to around minus 6/5 degrees Celsius. However, a
surface front, pushed by a building surface high pressure over the
western Atlantic, is expected to move over or close to the islands
and linger across the region over the weekend. The relatively
colder mid-level temperatures, combined with above-normal
precipitable water (PWAT) content of 1.50 to 1.70 inches, will
promote a wetter pattern across Puerto Rico and the U.S. Virgin
Islands in general during the first part of the long-term period,
with increasing chances of isolated thunderstorm development.

Consequently, there will be a limited to elevated risk of
excessive rainfall, leading to urban and small stream flooding and
potential landslides and rockfalls in vulnerable and steep
terrain. In the U.S. Virgin Islands, the highest probability of
precipitation (40% to 60%) will occur from late Friday through the
weekend as shower activity increases due to the expected frontal
passage.

An upper-level ridge building from the western Caribbean and a
developing TUTT-low northeast of the Leeward islands will promote
a drying trend across the local area for Monday and Tuesday, with
PWAT values dropping between 1.00-1.20 inches. Meanwhile, the
surface high pressure over the western Atlantic will strengthen,
and the low-level winds will increase between 20 and 25 knots
across the Atlantic waters and the Anegada Passage, particularly
on Monday. Therefore, breezy conditions and an advective weather
pattern are expected, with passing showers moving at times across
the windward areas of the islands and limited afternoon shower
development over the SW quadrant of PR.


&&

.AVIATION...

(06Z TAFs)

All TAF sites should experience VFR conditions. VCSH will affect
TJPS and TJBQ after 11/18Z. Winds will prevail from the SE around
4 to 14 kt with sea breeze variations.


&&

.MARINE...

A surface high pressure will build and migrate toward the central
Atlantic early this week, while a surface low and associated front
moves across the western Atlantic. Winds will prevail from the
east-southeast today, becoming lighter and from the south on
Wednesday. By the end of the week, the potential for showers over
the local waters will increase as the front moves closer to the
area, and winds turn from the east to northeast. Another long-period
northerly swell will spread across the Atlantic waters and local
passages next weekend, resulting in hazardous seas.


&&

.BEACH FORECAST...

There is a low to moderate risk of rip currents across the islands
today.

A 4 to 5 ft northerly swell will spread across the Atlantic
waters on Thursday and Friday, increasing the potential for life-
threatening rip currents. A larger swell (6 to 8 ft) is expected
later during the weekend, causing large breaking wave action along
the north-facing beaches of the islands. High surf advisory
conditions and life-threatening rip currents are likely,
particularly on Sunday.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
408 AM AST Wed Mar 12 2025

.SYNOPSIS...

A broad surface low over the western Atlantic will move into the
central Atlantic by Thursday, while an associated surface front
extending north of Hispaniola will continue to sink further into
the northeastern Caribbean during the next few days. At upper
levels, a series of troughs will provide some instability to
enhance showers with possible isolated thunderstorms over the
local area. The wettest period is expected from Thursday through
Saturday. A drying trend is forecast for early next week.

A long-period northwesterly swell will spread across the Atlantic
waters and local passages on Thursday, resulting mainly in
life-threatening rip currents. Another larger northerly swell is
expected to fill across the local waters during the weekend,
promoting hazardous seas and rough surf conditions.


&&

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

Clear skies prevailed across most of Puerto Rico overnight, with fog
developing along the Cordillera Central. Overall, calm and stable
conditions dominated across Puerto Rico and the U.S. Virgin Islands.
Temperatures remained in the low to mid-70s in coastal and urban
areas, while mountainous and rural regions remained in the 60s.
Winds were light and southerly.

Today, the ridge aloft will begin to weaken as an upper-level trough
approaches the Northeast Caribbean from the west, gradually
increasing atmospheric instability. Afternoon convection driven by
sea breezes and local effects may develop over interior and western
Puerto Rico today.

On Thursday, winds will become variable, shifting from the south-
southwest before transitioning to a north-northeasterly flow.
Instability will further increase as mid-level temperatures drop to
around -7°C while moisture levels extend up to 500 mb. These
conditions suggest that any developing showers will have a higher
potential for vertical growth, increasing the likelihood of stronger
development. As a result, the risk of thunderstorms and heavy
rainfall will rise, with further intensification expected by the end
of the workweek.

By Friday, an approaching frontal boundary will enhance shower
activity throughout the day, with stronger afternoon convection
anticipated over interior and southwestern Puerto Rico. Isolated
thunderstorms are expected, particularly with the heaviest rainfall.
At this time, there is an elevated risk of flooding across the
islands, meaning that flooding in urban areas, roads, small streams,
and washes is expected, along with a low chance of isolated flash
floods.

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

A mid-to upper-level trough will move over the Anegada Passage on
Saturday, and the 500 mb temperature will remain around -6/5
degrees C. This will promote marginal instability aloft for
isolated thunderstorm development. A stalled surface front over
the islands will continue to promote above normal moisture content
across the local area with precipitable water (PWAT) content
fluctuating between 1.50 to 1.70 inches. Therefore, a wetter
pattern is expected to continue across Puerto Rico and the U.S.
Virgin Islands, with a limited to elevated risk of excessive
rainfall, leading to urban and small stream flooding and potential
minor landslides in steep terrain. Lingering moisture across the
area will continue on Sunday as the front moves further south
under moderate to locally fresh northeast winds.

For the first half of the week, an upper-level ridge building
from the western Caribbean and a developing TUTT-low northeast of
the Leeward islands will promote a drying trend across the local
area, with PWAT values dropping between 1.00-1.20 inches.
Meanwhile, the surface high pressure over the western Atlantic
will strengthen, and the low-level winds will increase up to 20
knots across the Atlantic waters and the Anegada Passage,
particularly on Monday. Therefore, breezy conditions and an
advective weather pattern are expected, with shallow passing
showers moving at times across the windward areas of the islands
and limited afternoon shower development over the SW quadrant of
PR.


&&

.AVIATION...

(06Z TAFs)

All terminals should experience VFR conditions. VCSH will affect
TJPS and TJBQ after 12/17Z. and TJSJ, TIST, and TISX after 12/23Z.
Winds will prevail from the SE around 4 to 10 kt with sea breeze
variations. A gradual increase in rainfall is anticipated across all
TAF sites from this evening onwards.


&&

.MARINE...

A surface high pressure over the far eastern Atlantic and a
surface low and associated front moving over the western Atlantic
will maintain a southerly wind component through this morning.
Winds will become light and variable, but with a northerly
component later in the afternoon. By the end of the week, the
potential for showers over the local waters will increase as the
front moves closer to the area, and winds turn from the east to
northeast. A long-period northwesterly swell will spread across
the Atlantic waters on Thursday and linger through Friday. Late in
the weekend into early next week, a larger northeasterly swell
will bring hazardous seas once again across the Atlantic waters
and passages.


&&

.BEACH FORECAST...

The surface low over the western Atlantic will produce a long
period northwesterly swell that will arrive across the local
waters on Thursday. Life-threatening rip currents are likely
across the north-facing beaches of the islands. Seas are forecast
to build up to 6 feet across the Atlantic waters, but model
guidance could be underestimating the swell height and high surf
advisory conditions cannot be ruled out across some of the
northern beaches of Puerto Rico. This swell will increase the risk
of life-threatening rip currents across the northern exposed
beaches of the islands through at least Friday.

A larger northeasterly swell with seas building up to 8 feet is
expected late in the weekend into early next week, causing large
breaking wave action along the north-facing beaches of the
islands. High surf advisory conditions and life-threatening rip
currents are likely, particularly on Sunday and Monday.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
516 AM AST Thu Mar 13 2025

.SYNOPSIS...

A front just north of the area will slowly sink southwards during
the next few days. Aloft, a series of troughs will provide some
instability, enhancing shower development with possible isolated
thunderstorms over the local area. The wettest period is expected
from today through Saturday. A drying trend is forecast for early
next week.

A long-period northwesterly swell will spread across the Atlantic
waters and local passages today, resulting in high surf conditions
and life-threatening rip currents. Another larger northeasterly
swell is expected late in the weekend, promoting hazardous seas
and rough surf conditions through early next week.


&&

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

Showers developed later in the night, mainly across Atlantic water
and into windward sections of the local islands. Doppler radar
rainfall estimates reached half an inch in northwestern portions of
PR. Minimum temperatures in lower terrains remained in the mid to
upper 70s while stations in the higher terrains reported low to mid
60s.

The short term forecast remains on track. A wetter and unstable
pattern is expected for the next few days as a frontal boundary
continues moving across the region. Current satellite-derived
products show PWAT values increasing associated with the frontal
boundary. Latest model guidance suggests an increase of moisture
content in the low to mid level layers, with PWAT values will above
climatological normal (up to 1.9 inches). The combination of local
effects, high moisture content, and see breeze convergence will
enhance convection activity each afternoon, mainly over the
Cordillera Central. With the variable slow winds, showers developing
over theses areas shall remain longer and leave significant rainfall
accumulations, increasing flood potential. Therefore, ponding of
water in roadways, urban, and poorly drained areas is very likely,
along urban and small streams flooding each day. As a series of
upper level troughs move nearby the CWA and increase instability
aloft, and 500 mb temperatures ranging from -6 to -8 Fahrenheit, the
chance of isolated thunderstorm is likely each afternoon.

Temperatures will remain seasonal, with highest temperatures in the
mid to upper 80s in the urban and coastal areas while the interior
sections might experience low to mid 70s.


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

Lingering moisture from the remnants of the front will continue across
the area on Sunday. Moderate east to northeast winds will prevail
in general, and afternoon showers should develop mainly over the
interior and west/southwest portions of Puerto Rico. Across the
USVI, passing showers could move briefly over land areas, and
mainly during the morning hours as the old frontal boundary is
expected to move over the Caribbean waters, and further away of
the islands.

For the first half of next week, an upper-level ridge building
from the western Caribbean and a developing TUTT-low northeast of
the Leeward islands will promote a drying trend across the local
area, with precipitable water (PWAT) values dropping between
1.00-1.25 inches. Meanwhile, the surface high pressure over the
western Atlantic will strengthen, and the low-level winds will
increase up to 20 knots across the local waters by midweek.
However, another pulse of shallow moisture from a weak front over
the Atlantic waters is expected to reach the area by Tuesday
morning and the PWAT increases to near 1.50 inches. Therefore,
breezy conditions and an advective weather pattern are expected to
prevail, with showers increasing in coverage on Tuesday across
the windward areas of the islands, and diurnally induced afternoon
showers developing over the SW quadrant of PR. Model guidance
suggest a deep upper level trough reaching the northeastern
Caribbean late in the forecast period, with 500 mb temperatures
forecast to drop to near -10C, well below normal levels. Although
this can enhance thunderstorm activity during the afternoons, the
overall moisture content is forecast to remain low at this moment.


&&

.AVIATION...

(06z TAFs)

Mainly VFR conds across all TAF sites. However, a frontal boundary
moving from the Atlc waters will bring occasional periods of -RA/+RA
across JBQ/JSJ through the morning hours, and to JPS after 18z,
reducing CIG/VIS and tempo MVFR conds. Winds will remain N-NE
from 5 to 10 kt btw 13/15-13/23z, becoming light and vrb after
13/23z.


&&

.MARINE...

A surface high pressure over the far eastern Atlantic and a
surface low and associated front moving over the western Atlantic
will maintain light to moderate northeast winds for the next few
days. The potential for showers over the local waters will increase
through at least Saturday as the front moves across the region. A
long-period northwesterly swell will continue to spread across the
Atlantic waters through Friday. Late in the weekend into early next
week, a larger northeasterly swell will bring hazardous seas once
again across the Atlantic waters and passages.


&&

.BEACH FORECAST...

A long period northwest swell will promote high surf conditions
and life-threatening rip currents across most northern beaches of
PR, Culebra, and the U.S. Virgin Islands today. The swell will
slowly subside by late Friday and the high risk of rip currents
will persist through at least Friday evening. A larger northeast
swell will fill across the local waters from Sunday through early
next week, promoting high surf advisory conditions and an increase
risk of life-threatening rip currents once again.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
338 AM AST Fri Mar 14 2025

.SYNOPSIS...

A front will stall over the local area through at least Saturday,
promoting a wet weather pattern over the islands. An upper level
trough will provide some instability, enhancing shower development
with possible isolated thunderstorms today. A drying trend is
forecast from Sunday through early next week. A polar trough and
another front are expected to move near the area on Wednesday.
Long period northerly swells will cause life-threatening rip
currents, mainly across the northern beaches of the islands today
and on Sunday.


&&

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

A very wet night prevailed as strong showers moved mainly over
eastern and northern Puerto Rico, and St. Thomas and St. John in the
U.S. Virgin Islands due to the passing of a frontal boundary.
Elevated to significant Doppler radar rainfall estimated ranged from
1 to 4 inches along these sectors, with localized areas such as Toa
Baja, Bayamón, and other reaching 5 inches. Flood advisories and
Flash Flood Warnings were issued. Rivers and streams including Río
Blanco in Naguabo, Río Grande de Manatí, Río Grande Loíza, and
Quebrada Margarita in Guaynabo were under minor to moderate flooding
stage. Minimum temperatures remained lower today, with stations in
urban and coastal areas reporting mid to upper 70s with localized
areas in the low 70s while interior sectors remained in the low to
mid 60s.

The outlook for this weekend remains wet and unstable, with an
improvement in weather conditions by Sunday. The frontal boundary
will continue moving across the region and linger today and
Saturday. The latest model guidance suggests that PWAT values remain
above climatological normals (1.6 - 1.8 inches), mostly higher than
normal moisture content between low to mid-level layers, and 850-700
mb lapse rates will remain above normal (5-6 C/km). Winds will
remain light from the NE, dragging high moisture content over the
CWA. This, in combination with local effects, sea breeze
convergence, saturated soils, and moderate to high streamflows will
enhance shower activity once again, increasing flood potential
mainly over the northern, eastern, and interior PR, including
Vieques, Culebra, and the U.S. Virgin Islands. Rainfall
accumulations will leave significant amounts that will enhance urban
and small streams flooding, including isolated flash floods.

Drier air will filter later on Sunday, bringing stability and mostly
fair weather as the highest moisture content will remain over the
offshore Caribbean waters. Maximum temperatures will remain
seasonal, from low to mid 80s for the lower terrains and mid to
upper 70s for higher terrains.

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

At least through early Tuesday, an upper-level ridge building from
the western Caribbean and a developing TUTT-low northeast of the
Leeward islands will promote a drying trend across the local area,
with precipitable water (PWAT) values dropping between 1.00-1.25
inches. Meanwhile, the surface high pressure over the western
Atlantic is now forecast to weaken and move further into the north
central Atlantic as the TUTT-low induces a surface low northeast of
the region, and a deep polar trough with associated surface front
moves into the western Caribbean by Tuesday. This synoptic pattern
will cause winds to become light and variable, with weak sea breezes
dominating the steering winds on Monday and Tuesday.

By midweek onwards, the polar trough and surface front are expected
to move across the northeastern Caribbean. In response, the steering
winds will acquire westerly component, but a col area will develop
over or just north of the area, maintaining light and variable winds
in general. The 500 mb temperatures are forecast to drop below normal
levels around minus 8C on Wednesday, while low-level moisture
increases gradually from around 1.25 inches on Wednesday to 1.75
inches on Friday. Therefore, the potential for excessive rainfall
and isolated thunderstorm development will increase during the
second part of the workweek.


&&

.AVIATION...

(06z TAFs)

Mostly VFR conds for JPS, JBQ, and ISX for the TAF prd. The frontal
boundary will linger and bring SHRA for IST and JSJ and reduce
CIG/VIS through at least 14/22z, therefore, tempo MVFR to brief
IFR conds are possible across these terminals. NE-ENE winds at 5-10
kt for most terminals sites btw 14/13-23z, with gusty winds for
JBQ around 14/18z. Winds will become lighter after 14/23z.


&&

.MARINE...

A surface high pressure over the far eastern Atlantic and a
surface low and associated front moving over the western Atlantic
will maintain light to moderate northeast winds for the next few
days. The potential for showers over the local waters will increase
through at least Saturday as the front moves across the region. A
long-period northwesterly swell will continue to spread across the
Atlantic waters through today. Late in the weekend into early next
week, a second pulse of the swell from the northeast could bring
hazardous seas once again across the Atlantic waters and passages.


&&

.BEACH FORECAST...

Slowly subsiding swell today will maintain a high risk of rip
currents across the northern beaches of Puerto Rico, Culebra, St.
Thomas and St. John. A second pulse of the swell but from the
northeast will spread across the local waters from Sunday through
early next week, promoting life-threatening rip currents once
again across the north and east facing beaches of the islands.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
459 AM AST Sat Mar 15 2025

.SYNOPSIS...

Today's instability will decrease as the trough moves away from
the Northeast Caribbean. However, afternoon convection will result
in localized flooding this afternoon. Maximum temperatures in
urban and coastal areas will range between the low and mid 80s,
with localized areas reaching the upper 80s, and in the mountain
areas in the mid to upper 70s. Another mid-to upper- level trough
will amplify from Tuesday onward, with moisture ramping up from
Wednesday onward.

&&

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

Mainly fair conditions prevailed last night, with few clouds moving
over the local area. At this time, stations reported minimum
temperatures slightly colder than yesterday, with lower elevations
of low to mid 70s while higher terrains observed low to mid 60s.

Today will be the wettest day of the short-term period, with a more
stable pattern for the start of the week. The stationary front
remains east of the region, along with a low surface pressure north
of the CWA that will keep winds variable with a northeasterly
component. The latest model guidance suggests that Precipitable
Water values will remain near above normal values (1.4 - 1.5
inches), with enough moisture content for the development of showers
today. Eastern portions of Puerto Rico and the U.S. Virgin Islands
have the highest chance of precipitation in morning. The combination
of local effect, diurnal heating, and sea breeze convergence will
enhance convection activity in the afternoon, mainly over the
interior and southern portions of Puerto Rico. There's a high chance
of observing ponding of water in roadways, urban, and poorly drained
areas, with isolated urban and small streams flooding. A drier air
mass will filter into the region early Sunday, bringing stability
and fair conditions into the CWA through Monday. Even though PWAT
values will decrease to below normal values, there's a medium chance
of shower development over interior PR in the afternoon. As the
upper-level trough continues moving away from the local area, warmer
500 mb temperatures and drier air in the mid levels will inhibit
deep convection activity and lower the chance of thunderstorm
activity for the rest of the forecast period.

Temperatures will remain seasonal today, with maximum temperatures
in urban and coastal areas in the low to mid 80s, with localized
areas reaching the upper 80s, and higher elevations in the mid to
upper 70s.

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

On Tuesday, the interaction between an induced surface low in the
Central Atlantic and a cold front moving eastward across the
Western Atlantic will create light and calm winds across the
islands. The Total Precipitable Water (TPW) is expected to be
around one inch, which is below normal and drier than usual for
this time of year. Additionally, a mid to upper-level trough will
approach from the west, potentially enhancing afternoon convection
driven by the sea breeze.

Moisture levels will begin to rise on Wednesday as the frontal
boundary draws nearer to the islands. From Thursday onward,
moisture will pool from the east to east-southeast due to the pre-
frontal trough on Thursday and Friday. This will be followed by
additional moisture being lifted by the low over the Central
Atlantic around Saturday. Instability will be enhanced as the mid-
to upper-level trough also amplifies over the Northeast Caribbean.

&&

.AVIATION...
(06z TAFs)

Mainly VFR conds will prevail at all terminals. Showers associated
with the frontal boundary will enhance -RA/+RA for IST and ISX
around 15/13z and SHRA for JPS after 15/19z, which may reduce CIGs
and lower VIS with temp MVFR conds. Mainly N-NE winds from 5 - 10 kt
btw 15/13-15/23z, then calm to light winds after 15/23z.

&&

.MARINE...

A surface low and associated front moving over the western Atlantic
will maintain light to moderate northeast winds for the next few
days. A long-period northwesterly swell will continue to subside
throughout the day. Another northeast swell will bring hazardous
seas once again late tonight into early next week across the
Atlantic waters and passages.

&&

.BEACH FORECAST...

A subsiding northerly swell will result in moderate to high rip
current risk along the northern coast of Puerto Rico, from Rincon
to Fajardo, as well as northern exposed beaches of Culebra, St
Thomas and St. John. Another pulse of a long-period northerly
swell will spread across the Atlantic waters and local passages
later tonight, increasing breaking waves and promoting life-
threatening rip currents once again. Therefore, the High Rip
Current Risk was extended through late Sunday night.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
449 AM AST Sun Mar 16 2025

.SYNOPSIS...

Light and variable winds will dominate the region through the
first part of the week. Afternoon convection will develop each day
and will result in periods of moderate to locally heavy rain.
Maximum temperatures will reach the mid and upper 80s, especially
in urban and coastal areas. Another mid-to-upper-level trough will
amplify from Tuesday onward, with moisture ramping up from
Wednesday onward due to an approaching frontal boundary and
prefrontal trough.

&&

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

The night remained calm with primarily fair weather across the local
islands. Minimum temperatures were slightly colder tonight, with
stations in lower elevations reporting low to mid 70s, and localized
areas in the upper 70s. Higher terrains observed low to mid 60s, and
a station in Jayuya reported upper 50 temperatures.

Current satellite-derived products show a drier air mass filtering
into the region. Model guidance agrees that a drier trend will
dominate for the short-term forecast, along with shallow convection
in the afternoons. The surface low pressure northeast of the CWA
will migrate to the north as it interacts with the high surface
pressure in the western Atlantic. This will maintain variable NE
winds today and on Monday, with a col region near the region that
will additionally maintain light winds. Even though the PWAT values
are expected to drop below the climatological normal (0.9-1.0 inch),
the combination of local effects, diurnal heating, and sea breeze
convergence will increase the chance of showers mainly over interior
Puerto Rico. With the col region nearby, showers that develop in the
area will likely stay longer and increase the chance of observing
rainfall accumulations in roadways, urban, and poorly drained areas.
On Tuesday, however, winds will continue to vary but with a westerly
component as another frontal boundary and its pre-frontal trough
approach the region. A deep layered trough will induce a low
pressure near the region, increasing instability. However, the
chance of convection activity will remain low due to below normal
moisture content in the low and mid layers.

Maximum temperatures today will once again remain in season, with
urban and coastal areas in the mid to upper 80s and interior
sections in the mid to upper 70s. There's a trend of 925 mb
temperatures increasing to above normal values, being Tuesday the
warmest day of the period.

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

Moisture levels will begin to rise on Wednesday as the frontal
boundary draws nearer to the islands from the west with a mid-to-
upper-level trough increasing instability. From Thursday onward,
moisture will pool from the east to east-southeast due to the
prefrontal trough on Thursday and Friday. Thus, the second part of
the workweek looks at this time unstable and with good available
moisture to bring periods of flooding rains, especially in the
afternoon and evening hours.

By next weekend, the interaction between a high pressure migrating
eastward from the Western to Central Atlantic with a surface low
will promote moisture pooling over the Northeast Caribbean on
Saturday and Sunday.

&&

.AVIATION...
(06z TAFs)

VFR conds for all TAF sites. Shallow convection in the afternoon
will bring -RA to JPS around 16/19z, which may temporarily reduce
CIG/VIS. VRB winds with an NE component from 5-10 kt in the morning
around 13-15z, then around 5 kt for most terminals after 16/23z.

&&

.MARINE...

A surface low and associated front northeast of the area will
maintain light to moderate northeast winds for the next few days. A
north-northeast swell will move across across the Atlantic waters
and passages through early this week. Another cold front with its
associated surface low will move eastward from the western to
central Atlantic, approaching the region by the middle of the week
and promoting the light and variable wind flow.

&&

.BEACH FORECAST...

A pulse of a long-period north-northeasterly swell spreading
across the Atlantic waters and local passages will promote life-
threatening rip currents along the north facing beaches from
Rincon to Fajardo, Culebra and the northern US Virgin Islands.
Therefore, the High Rip Current Risk continues in effect through
late tonight.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
350 AM AST Mon Mar 17 2025

.SYNOPSIS...

Variable weather conditions are expected today across the region,
as pockets of moisture move into the area with light to moderate
showers moving into the eastern portions of Puerto Rico and the
USVI in the morning. Afternoon convective activity is expected
across the interior and western Puerto Rico today. By midweek a
cold front will move into the area promoting additional shower
activity that could result in a limited to elevated risk of
flooding across the islands. Marine and coastal conditions will
continue to deteriorate today, as pulses from a long-period
northerly to northeasterly swell continue to arrive into the
islands.

&&

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

Calm weather conditions prevailed overnight, with a few showers
across the Atlantic Waters and some making their way into the
windward sections of PR and the northern VI. Winds prevailed from
the north to the northeast. Some stations along the mountains and
valleys reported temperatures in the low 60s and even the upper 50s.
A long-period northeasterly swell, moving across the Atlantic waters
and reaching the Atlantic coastline, created life-threatening rip
currents along the north and northeast-facing beaches in PR and the
northern USVI.

A ridge pattern aloft will promote a stable atmosphere at the mid
and upper levels. However, a surface low-pressure northeast of the
islands will push pockets of moisture and clouds to the islands,
bringing occasional showers across the windward sections.
Additionally, winds will prevail today light from the north to
the northeast under sea breeze variations. Later in the afternoon,
local effects will promote convection, and model guidance
suggests that most of the activity will affect the northeast and
interior, spreading into the south and west. Although we are not
anticipating widespread flooding, periods of heavy rain will
produce ponding of waters across these locations, where isolated
flooding cannot be ruled out.

A mid-to upper-level trough will begin approaching the islands by
Tuesday, and there will be a cold front at the low levels, which, on
that day, should be near the Hispaniola. A col will be located near
the islands, promoting calm to light and variable winds, mainly from
the southwest by the afternoon. As a result, model guidance suggests
the afternoon activity developing along the Cordillera Central and
eastern half of Puerto Rico and slowly spreading toward the east
into the US Virgin Islands by the late afternoon or evening. A
prefrontal trough will approach the islands by late Tuesday into
Wednesday, and a jet stream will accompany the trough on Wednesday.
As the cold front approaches PR/USVI from the west, winds will shift
from the north-northwest by late Tuesday night or Wednesday,
increasing by the morning and possibly becoming breezy and northerly
by the afternoon. Currently, the limiting factor for Wednesday's
activity is the low concentrations suggested by model guidance;
however, we will keep you posted as the event evolves, which may
result in a higher risk of flooding rains.

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

Moisture associated with a mid-to-upper level trough will begin to
move over the islands from Caribbean waters on Thursday into the
weekend. Under this pattern, showers are anticipated over the
eastern portions of Puerto Rico and the U.S. Virgin Islands in the
morning hours, followed by afternoon convection over the interior
and western Puerto Rico in the afternoon. Winds will be light and
variable, mostly from a south southeasterly component. Therefore,
promoting the heaviest rainfall activity over the interior,
northwestern portions of Puerto Rico and adjacent municipalities
due to the combination of the available moisture, diurnal heating
and local effects. By Saturday, moisture content is expected to be
near or at 1.6 inches, suggesting the development of additional
rainfall activity, particularly over the interior and western
Puerto Rico.

Winds are expected to shift from the east on Saturday night into
Sunday as a strong surface high pressure moves from the western
Atlantic into the central Atlantic, pushing away the low pressure in
the central Atlantic. The interaction of both systems in the
Atlantic will continue to promote the arrival moisture areas into
the region through early next week. The 925 mb temperatures will
remain normal to below-normal during the period. Highs are
expected to be in the mid to upper 80s and low 90s along the
coastal and urban areas, and in the upper 70s, to the low to mid
80s in the mountains and higher terrains.

&&

.AVIATION...
(06Z)

VFR conditions will persist across the TAF sites during the period.
Winds will continue from the N to NE between 5 and 13 kt with
occasional higher gusts and sea breeze variations after 17/13z.
Occasional SHRA embedded in the winds will affect the area
throughout the day. SHRA/-SHRA will develop across the interior,
spreading into the south and west between 1717z-1800z.

&&

.MARINE...

A surface low to the northeast of the area will keep light to
moderate northerly to north-northeast winds in place over the next
few days. This surface low has generated a long period northeasterly
swell, which is expected to worsen marine and coastal conditions in
the Atlantic waters today. In addition, another cold front with an
associated surface low will move eastward from the western to central
Atlantic, reaching the region by the middle of the week. This may
lead to light and variable wind conditions. However, there is a
slight to moderate chance of experiencing moderate to fresh
northerly winds as the front approaches. Furthermore, another long-
period northwesterly swell is expected to arrive in the latter part
of the workweek.

&&

.BEACH FORECAST...

A pulse of a long-period north-northeasterly swell spreading
across the Atlantic waters and local passages will promote life-
threatening rip currents and hazardous breaking waves along the
north facing beaches from Rincon to Fajardo, Culebra and the
northern US Virgin Islands. Therefore, a High Rip Current Risk is
in effect through late this evening. In addition, a High Surf
Advisory will be in effect from this morning through late this
evening.