Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
504 AM AST Fri Nov 8 2024

.SYNOPSIS...
Unsettled weather is returning later today and will
likely stick tonight, bringing more showers and thunderstorms. With
saturated soils, flooding impacts are possible. Are you planning to
head out on the water? You might want to rethink that—hazardous seas
and life-threatening rip currents will continue today. The good
news? Marine and coastal conditions should improve during the
weekend, although stormy weather may disrupt some outdoor plans.
Sunday, however, is looking more promising. Stay safe and informed
by following us on our social media channels! For the latest updates
on excessive rainfall, rip currents, and other hazards, visit the
Experimental Graphical Hazard Weather Outlook:
https://www.weather.gov/erh/ghwo?wfo=sju.

&&

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

Overnight radar and satellite analysis indicate generally fair
weather conditions, except for the US Virgin Islands, where showers
and a few isolated thunderstorms generated isolated rainfall totals
of up to three quarters of an inch since 8 PM AST. Overnight
temperatures ranged from the lower 60s in higher elevations to
around 80 degrees across Vieques, Culebra, and the U.S. Virgin
Islands. Winds were generally light to calm and variable.

Despite relatively fair weather observed across the region in the
last 6 to 12 hours, unsettled weather will likely return. Before
drifting further to the southwest and away from the region, the
upper-level trough will maintain favorable conditions for
thunderstorm development today, with 500 mb temperatures at typical
levels, around -6 degrees Celsius. At the surface, the dominant
feature, a trough of low pressure, with the axis extending across
the forecast area, will continue its westward movement today.
Nonetheless, its induced weak southerly flow will continue to
support an influx of abundant tropical moisture. This feature will
be quickly followed by a robust tropical wave tonight into Saturday,
with its associated moisture lingering over the region through
Sunday. In agreement with model guidance, satellite-derived
precipitable water values across the region suggest above-normal
November levels holding through most of the period, fluctuating
between 2.1 and 2.3 inches. Consequently, this synoptic setup should
support frequent and strong thunderstorms over the next 24-48 hours,
with high rain chances (70-90%) across all land areas.

Since a weaker steering flow will increase the likelihood of higher
rainfall accumulations from slow-moving showers, an elevated risk of
excessive rainfall exists today, raising concerns for urban and
small stream flooding, with localized flash floods possible. On
Saturday, the risk was elevated to significant levels, raising even
higher concerns for flash and river flooding and mudslides across
the region. Additional hazards include frequent lightning and gusty
winds generated by thunderstorms. Despite the increased chance of
rain and cloudiness, southerly winds today will result in another
warm day, as indicated by warmer-than-normal 925 mb temperatures.

According to current model guidance, Sunday's weather pattern will
likely be less stormy, with more localized showers and isolated
thunderstorms, primarily in the afternoon. Flooding impacts are
likely to occur due to periods of moderate to locally heavy rainfall
over soils that are already saturated. For updates on excessive
rainfall, lightning, and any other hazard risk in the coming days,
please visit the Experimental Graphical Hazard Weather Outlook at
https://www.weather.gov/erh/ghwo?wfo=sju.

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

No major changes are expected during the long-term period. The mid
to upper levels will maintain stability, providing mostly dry
conditions and warmer temperatures at 500 MB, which will limit the
development of deep convection. At the surface, the islands will
be mostly dominated by a broad area of high pressure extending
from the western Atlantic into the central Atlantic, gradually
shifting eastward, driven by an upper-level low reflected across
all levels. By Monday, this pattern will result in moderate to
strong easterly wind flow across northern sections. Driven by this
wind flow, abundant moisture from the previous tropical wave will
spread across the islands, enhancing the potential for early
morning showers due to an advective pattern, as well as afternoon
convection triggered by diurnal heating across the western
interior.

From Tuesday through Friday, a surface low pressure system,
reflected at the mid-levels, will move southeastward in response
to an existing surface high pressure over the CONUS. This will
create a trough just northwest of the region, resulting in veering
winds—shifting to east-southeast by Tuesday, southeast by
Thursday, and light to variable by Friday. As the week progresses,
columnar moisture is expected to decrease from Thursday to Friday
with PWAT as the global models suggest of 1.4 to 1.5 inches.

&&

.AVIATION...

(06Z TAFS) VFR conditions will prevail through 08/12-14Z. SHRA/TSRA
later this morning, bringing brief MVFR/IFR conditions at TJPS and
USVI terminals after 08/14Z, and at TJSJ/TJBQ after 08/17Z. Periodic
SHRA/TSRA pulses, associated with an approaching tropical wave, may
affect operations at all TAF sites after 09/00Z. Winds will remain
light to calm and variable, increasing to 5-10 knots from the south-
southeast, with higher gusts possible near TSRA activity.

&&

.MARINE...

Hazardous marine conditions will persist for at least the rest of
the day, improving during the night hours as energy from the
previous northerly swell and winds diminish across the local
islands. Starting tomorrow, seas will remain at 5 feet or less due
to a weakening in the pressure gradient resulting from a trough
associated with a low-pressure system moving across the region.
Additionally, local waters will experience an increase in
thunderstorm activity, leading to hazardous localized marine
conditions. A tropical wave will move northwestward into the area
by Saturday into Sunday, resulting in similar conditions and
increasing wind speeds by Monday.

&&

.BEACH FORECAST...

Recent data buoy at San Juan reported large breaking waves at
around 9 feet. Similar conditions will persist for the rest of the
morning hours across the northern section of Puerto Rico, where
hazardous swimming conditions will prevail. Given the actual
conditions, there is a high rip current risk across all the north
PR and Culebra. Beachgoers are urged to remain out of the northern
exposed local beaches. Improving coastal conditions are forecast
from Saturday into Sunday with a moderate risk of rip currents.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
513 AM AST Sat Nov 9 2024

.SYNOPSIS...
A significant flooding threat is expected today through
Sunday due to widespread moderate to heavy rainfall from a passing
tropical wave. Flooding risks include urban, small streams, flash,
and river flooding, especially in areas with saturated soils. Rapid
river rises and the potential for mudslides are also significant
threats. By Monday, marine conditions will deteriorate as a
northerly swell arrives, bringing hazardous seas and life-
threatening rip currents along exposed coastlines. Stay informed on
the latest updates for flooding, rip currents, and other hazards
through our social media channels and the Experimental Graphical
Hazard Weather Outlook: https://www.weather.gov/erh/ghwo?wfo=sju.

&&

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

Overnight radar and satellite analysis showed an active weather
pattern, with showers and isolated thunderstorms over the waters,
some of which brushed the U.S. Virgin Islands and southeastern,
eastern, and northeastern coastal areas of Puerto Rico. A few
showers moved further inland into eastern Puerto Rico. Surface
observations recorded rainfall totals of up to a quarter of an inch
in Puerto Rico's eastern interior since 8 PM AST. At the same time,
radar estimates showed around three-quarters of an inch of rain over
eastern Saint John, USVI. Temperatures ranged from the mid-60s in
higher elevations to above 80 degrees across south-central and
northeastern Puerto Rico, Culebra, and the U.S. Virgin Islands.
Winds were generally light and variable, with stronger gusts near
thunderstorms.

With a passing tropical wave bringing abundant tropical moisture
well above typical November levels, the short-term forecast focuses
on significant rainfall and flooding risks from today through
Sunday. Moderate to heavy rain from frequent showers and strong
thunderstorms will result in an elevated to significant excessive
rainfall risk across the region. Therefore, any daily decision
should account for this heightened flooding threat.

The tropical wave will also bring thunderstorms with frequent
lightning, strong, gusty winds, and breezy to windy conditions in
parts of the islands. Initially, rainfall will come from showers
moving inland from nearby waters this morning, followed by afternoon
thunderstorms fueled by daytime heating and driven by local effects.
As the wave continues across the region, it will drive the heaviest
rainfall tonight over eastern Puerto Rico, where recent rain has
left soils saturated and elevated streamflows, significantly
increasing the flooding risk. A similar pattern will repeat on
Sunday, with morning rainfall over eastern areas and the local
islands, then additional showers and thunderstorms in the northwest
in the afternoon.

A Flash Flood Watch is in effect from late this morning through
Sunday evening, with potential impacts ranging from urban and small
stream flooding to flash and river flooding, especially in saturated
areas. Rapid river rises are also likely, creating potential dangers
for anyone visiting local rivers. Those who choose to visit should
monitor conditions closely and stay informed of any guidance from
local authorities.

As the tropical wave departs by Sunday night into Monday, conditions
should improve; however, lingering moisture will likely continue to
generate rainfall across the area. While flooding risks will
subside, the risk will remain elevated. Warmer temperatures will
also return on Monday, with potential heat impacts for those
sensitive to warmer conditions, particularly outdoors without
adequate cooling and hydration. For updates on excessive rainfall,
lightning, and any other hazard risk in the coming days, please
visit the Experimental Graphical Hazard Weather Outlook at
https://www.weather.gov/erh/ghwo?wfo=sju.

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

For the long term, variable weather conditions will prevail as mid
to upper-level ridges hold for most of the period, providing
stable conditions. Although drier intrusion at the mid to upper
level will remain in place for Wednesday, tropical moisture
trapped in the lower levels will reach the islands driven by the
east-southeast winds resulting from the interaction of a broad
surface high pressure over the Central Atlantic and a frontal
boundary and the associate low pressure sinking southeastward. This
change in the surface will induce a more east-southeast across
the islands. Under this pattern for Wednesday, a drier airmass
will reach the islands, limiting the widespread shower activity.

Stable conditions will not last much, and by Thursday, the
approach of moisture from a frontal boundary and a change in the
surface winds will enhance the showery pattern across the islands
again. Although the moisture from this feature moves near and over
the region on early Thursday, good convection is forecast for the
afternoon hours across the northeastern section of the islands
due to the northeast wind flow dominating the area. By Friday into
Saturday, as the global model guidance suggested, after the
Frontal Passage (FROPA), much drier air will dominate the pattern
with less shower activity and much colder temperatures.


&&

.AVIATION...

(06Z TAFS) A passing tropical wave will increase SHRA/TSRA, likely
causing brief periods of MVFR to IFR conditions across most
terminals, which could affect operations, particularly after 09/16Z.
Winds will initially be light and variable, increasing to 8-12 knots
between 09/14-21Z, with possibly higher gusts near TSRA.

&&

.MARINE...
A surface trough will result in light to moderate winds from the
east-southeast and will prevail into the weekend. Winds are
forecast to increase again by Sunday afternoon after the passage
of the upcoming tropical wave. Seas will remain up to 5 feet for
the entire weekend, increasing by midweek. A tropical wave will
increase shower and thunderstorm activity resulting in localized
hazardous marine conditions during the weekend.

&&

.BEACH FORECAST...
Improving conditions let a moderate to low risk of rip current
across all the exposed beaches of Puerto Rico and the U.S. Virgin
Islands today. For Monday, the risk of rip current will return for
PR's northern coast. Although conditions might be suitable for
visiting the beaches, an increase in thunderstorms might result in
hazardous coastal conditions across the islands until Sunday.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
538 AM AST Sun Nov 10 2024

.SYNOPSIS...
A broad area of low pressure extending across the region from the
central Caribbean and a Tropical wave crossing the eastern Caribbean
will maintain a very moist and unstable weather pattern through the
holiday weekend and into early next week. Periods of moderate to heavy
rains with strong thunderstorms will affect the region through at
least Sunday evening or early Monday. This will result in a elevated
to significant rainfall risk. Expected hazards, include: urban and
small stream flooding, quick river rises, mudslides and flash flooding.
Therefore, a Flash Flood Watch will remain in effect for the islands
through at least Sunday evening. Rivers and streams will quickly react
to any additional rains with mudslides likely due to saturated and
loose soil. By Monday, marine conditions will deteriorate as a winds
increase and a northerly swell arrives. This will bring hazardous
seas and life- threatening rip currents along exposed coastlines.

&&

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

Overnight radar and satellite analysis showed an active weather
pattern, with showers and isolated thunderstorms over the waters and
most of the eastern sections of Puerto Rico. At around 3 AM, the
heaviest activity stopped across the islands. However, persistent
light rain remained across most of the southeastern section and the
vicinity of Caguas. According to the observations and radar,
rainfall accumulation fluctuated between 1 to 2 inches across
eastern sections. Several Advisories and warnings were issued with
the heaviest showers and across the municipalities where rivers
reacted. Temperatures ranged from the mid-60s in higher elevations
to above 80 degrees across south-central and northeastern Puerto
Rico, Culebra, and the U.S. Virgin Islands. Winds were generally
light and variable, with stronger gusts near thunderstorms.

For the rest of the day into Monday, the actual abundant tropical
moisture from the tropical wave moving over the region will continue
to provide unstable weather conditions for shower development during
the day. Given the forecasted conditions today and Monday, residents
should expect significant rainfall and flooding risks, with moderate
to heavy rain from frequent showers and strong thunderstorms resulting
in an elevated to significant excessive rainfall risk across the
region. Since soils across most of the northeast of Puerto Rico
are already saturated, flooding and mudslides will not take longer
to pose a threat today and tomorrow.

A Flash Flood Watch is in effect through this evening, with potential
impacts ranging from urban and minor stream flooding to flash and
river flooding, especially in saturated areas. Rapid river rises
are also likely, creating potential dangers for anyone visiting
local rivers. Those who choose to visit should monitor conditions
closely and stay informed of any guidance from local authorities.

By Tuesday, lingering moisture will likely continue to present across
the local islands; the lack of instability and upper forcing will
lead the islands to remain on a cloudy day with convection resulting
from the orographic effects and the diurnal effects. The southeasterly
wind flow across the region resulted from the interaction of a strong
surface high pressure and an upcoming frontal boundary that will focus
the showers across the northwestern sections and the northeastern sections
of PR. Saturated soils would lead to urban and small- stream
flooding as well.

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

Recent model guidance continued to suggest overall moist and variable
weather conditions to persist. Although mid to upper-level ridging
is expected to hold through early Wednesday, the continued low level
moisture convergent pattern will continue at least through the end
of the work week due to the approach of a frontal boundary/shearline
and associated moisture field which is forecast to reach the area,
as strong surface high pressure builds across the west and southwest
Atlantic. This in turn will induce a lighter east- southeast across
the islands by Friday then becoming more east to northeast during
the rest of the period.

Although a slightly drier pattern is expected early Wednesday these
conditions will be short-lived, as additional moisture convergence
and is expected with the aforementioned frontal boundary and the approach
of a mid to upper level polar trough which will slide eastward just
north of the region. Therefore overall good convection is forecast
for each day especially across the central interior and northeastern
sections of Puerto Rico and also in and around the U.S. Virgin Island
islands steered by the east to southeast wind flow on Wednesday, then
a more east to northeast wind flow by the end of the period. By late
Friday into Saturday, model guidance continue to suggest a gradual
drying tend with low level moisture erosion and weakening of the
mid to upper level troughiness. That said a drier patter is so far
expect by the weekend with more seasonal conditions and a mix of
sunshine and clouds followed by limited afternoon convection for
the islands.

&&

.AVIATION...

(06Z TAFS)
A tropical wave moving across the region will continue to produce
light RA across most eastern TAF sites until 10/13Z. After that,
SHRA and TSRA are forecast for most of the TAF sites with lower
VIS and clouds across FL020 and FL030 across the mountains and TAF
sites. Sfc winds were E-SE 6-12 kts with sea breeze influences
during the day and gusty winds near the showers.

&&

.MARINE...
Moderate to locally fresh winds from the east southeast will prevail
as a tropical wave crosses the region. Winds will increase by Monday
after the passage of a tropical wave and a surface high pressure
ridge builds north of the region. Moisture accompanying and
trailing the tropical wave will continue to increase of shower and
thunderstorm development across the local waters and passages
resulting in localized hazardous marine conditions during the rest
of the holiday weekend.

&&

.BEACH FORECAST...
There is a moderate to low risk of rip current across all the
exposed beaches of Puerto Rico and the U.S. Virgin Islands through
this evening. For Monday, the risk of rip current will become
high for the northern coast. Although conditions might be suitable
for visiting the beaches, the increase in thunderstorm activity might
result in hazardous coastal conditions across the islands through
this evening.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
540 AM AST Tue Nov 12 2024

.SYNOPSIS...

Trailing moisture from a tropical wave now west of our local islands
and from approaching frontal boundaries will mainly maintain above
normal moisture over the islands. Already saturated soils from previous
rains increase the risk of flooding, landslides and quick river rises.
Marine and coastal conditions will continue to deteriorate today
through at least mid week with the arrival of a northerly swell.

&&

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

Mostly cloudy skies persisted across the region overnight. However,
most of the shower activity over land diminished with only few noted
along the south and east coastal sections of Puerto Rico and around
the coastal waters of The U.S.Virgin Islands. So far no significant
rainfall accumulations were noted. Low morning temperatures were in
the upper 70s to near 80 degrees along the coastal areas and in the
interior and higher elevations the upper 60s to low 70s.

Steered by the prevailing ESE flow, residual trailing moisture from
the previous days tropical wave and that along a frontal boundary
just north of the region will maintain layered PWAT values above
2.00 inches. Weak mid to upper level ridging will also persist
through the period as an upper trough moves eastward and lingers
east to northeast of the region. A surface high will continue to
spread eastward across the Atlantic while remnants of the
aforementioned frontal boundary is expected to later sink southwards
towards the region. Consequently a moist environment is expected to
continue although widespread rainfall is not anticipated today
through Wednesday. However, showers may again affect the windward
side of the islands by the early morning hours. This will be
followed by afternoon and evening convection due to local and
diurnal effects as breaks in cloud cover will favor additional
shower development and potential isolated thunderstorm activity
across the islands particularly interior and west to northwest
sections of Puerto Rico, as well as downwind of the USVI. By
Thursday as the frontal boundary nears the region and the surface
high shifts farther northeast of the region, local winds will become
even lighter with a southerly component. Good heating and lesser
cloud cover with the available moisture will again favor afternoon
afternoon showers and thunderstorm development but the activity
should be more localized with still the potential for urban and
small stream flooding as well as mudslides due in to the already
saturated soil.

&&

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

Recent model guidance continues to suggest that moist and variable
weather conditions will persist across the region most of the
long term. Precipitable water values are expected to range from
normal to above normal values. By the end of the week, ridging
along the eastern Atlantic will support a southerly to southeasterly
wind flow, and a frontal boundary, which is expected to be
lingering north of our area, should weaken and move northward
with the flow. A col region will prevail across our region causing
light winds. Any rainfall that develops with the available moisture,
diurnal heating, and local effects is expected to move slowly.
With soils already saturated, minimal additional rainfall could
lead to flooding or landslides. On Saturday, patches of dry air
will move across the region, and we should have a less rainy day.
However, with the southerly winds, temperatures are expected to
rise a few degrees, reaching the upper 80s to lower 90s in urban
and lower elevations likely leading to afternoon convection and
isolated thunderstorms across the interior and northwest. By
Sunday and Monday, moisture levels are expected to increase again,
maintaining a good pool of tropical moisture and resulting in
moist and unstable conditions. Consequently, there will be a
continued threat for minor urban and small stream flooding across
portions of the islands, as well as ponding of water on roads and
in poorly drained areas. The potential for mudslides and unstable
terrain will persist, mainly from Sunday night through early next
week, due to the continued saturated soil conditions across much
of the forecast area.

&&

.AVIATION...

(06Z TAFS)

A tropical wave now south of Hispaniola and a frontal boundary
north of the region will maintain cloudy skies across the local
area. Cloud debris fm these features will lead to SCT-BKN Lyrs nr
FL025... FL050...FL080 and BKN-OVC nr FL250. SCT SHRA/Isold TSRA
will develop and affect the regional waters and areas en route btw
islands. VCSH likely at all terminals and VCTS psbl AT
TJSJ/TISX?TIST til 12/12Z. Prds of reduced VIS and low ceilings
with MTN top obscr psbl ovr E interior of PR due to SHRA/low cig.
Aft 12/17z, aftn SHRA/isold TSRA are fcst vcnty of TJBQ and ovr
ctrl interior of PR with VCSH elsewhere durg rest of prd. SFC wnds
calm to lgt/vrb bcmg fm ESE 10- 14 kts,with stronger gusts aft
12/14Z.

&&

.MARINE...

Trailing moisture from a tropical wave and a frontal boundary to
the north of the area will continue to promote showers and
thunderstorms across our local waters with moderate to locally
fresh east to southeast winds. Pulses of a northerly swell will
continue to reach the area today, deteriorating marine conditions
along the Atlantic waters and passages at least through mid week.

&&

BEACH FORECAST...

Beachgoers, there is a high risk of rip currents today and tonight
for the northern coast of Puerto Rico, from Rincón to Fajardo,
Culebra, Vieques, and the U.S. Virgin Islands. The risk is expected
to remain high for most areas at least until tomorrow afternoon
as a northerly swell energy spread across the region. In addition,
we anticipate large breaking waves around 10 to 14 feet across
all the northern coastal areas of Puerto Rico, where a High Surf
Advisory and a Coastal Flood Advisory are in effect from this
morning through at least 6 PM AST this afternoon. Also, thunderstorm
activity might result in hazardous coastal conditions across the
islands. We encourage resident and visitors to remain vigilant and
keep track of the forecast if planning beach activities. For more
details, please consult the Surf Zone Forecast (SRFSJU).

[cycloneye]

National Weather Service San Juan PR
521 AM AST Wed Nov 13 2024

.SYNOPSIS...

A less active day in terms of rain is expected, but the combination
of the light wind flow, daytime heating and local sea breeze
variations will result in afternoon showers and isolated
thunderstorms. The activity should be focused mainly over the
central interior and northern half of Puerto Rico. Already
saturated soils from previous rains increase the risk of flooding,
landslides and quick river rises. Deteriorated marine and coastal
conditions will continue through this afternoon due to pulses of
a northerly swell.

&&

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

Overnight mostly light to moderate passing showers steered by light
east-southeast crossed the local waters with a few reaching sectors
of eastern and southern Puerto Rico. Overall cloudiness and columnar
moisture continued to decay as a slightly drier airmass filtered in
from the east. Overnight low temperatures were in the mid 70s to
near 80 degrees along the coastal areas and in mid 60s to low 70s in
higher elevations. Winds were calm to light and variable overnight.

During the rest of today a less active weather pattern is forecast,
however with the combination of the light wind flow, good heating
and local sea breeze variations, afternoon showers and thunderstorms
will remain possible due to moisture availability. The activity
should be focused mainly over the central interior and northern half
of Puerto Rico. Some late afternoon and early evening showers and
isolated thunderstorms may also develop over the waters of local
passages and over the windward sectors of the islands.

By later tonight and on Thursday winds will become even lighter or
calm due to the approach of another frontal boundary and the surface
high pressure lifting farther north and east of the region,
resulting in an induced low level trough and col over the area. Weak
mid to upper level ridging will hold although slightly eroding due
to an upper short wave trough crossing just north of the region. As
this pattern unfolds, the moisture remnants of the aforementioned
frontal boundary is expected to sink southwards towards the region.
Consequently, the available moisture will promote early morning and
afternoon activity once again over the islands and coastal waters.
Also, with the light east northeast low level flow, overnight and
early morning shower will reach the parts of the north and east
coastal sections of the islands followed by afternoon convection due
to diurnal and local effects especially over the central and east
interior of Puerto Rico, eventually drifting north and east over the
surrounding areas, and mainly downwind of the USVI. Recent model
guidance continued to suggest a fairly moist and variable weather
pattern will persist most of the period. Precipitable water values
are expected to range near normal or just above above normal values
with more seasonal temperatures expected for the period. By the end
of the period, surface ridging over the northeastern Atlantic will
support a light south to southeasterly wind flow, with the moisture
remnants of the frontal boundary/shearline expected to linger just
north and east of the area while gradually eroding. Also keep in
mind, that any locally and diurnally induced shower activity that do
develop will move slowly or drift towards surrounding areas and
locally heavy rains will be possible. Therefore with soil already
saturated in most areas, even minimal additional rainfall could lead
to flooding or landslides across the islands.

&&

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

By the beginning of the long-term period, a surface high-pressure
system over the Southeast U.S. will begin to move across the
western Atlantic. This will be accompanied by a ridging pattern
over the eastern and central Atlantic, which will keep our region
under a southerly wind flow. This flow will maintain tropical
moisture pooling, resulting in moist and variable conditions
across the islands. With the southerly winds, temperatures are
expected to rise a few degrees, reaching the upper 80s to lower
90s in urban and lower elevations, likely leading to afternoon
convection and isolated thunderstorms across the interior and
northwest.

At the upper levels, a deep-layer trough will continue to sweep
across the Atlantic, and its associated cold front is expected to
approach and cross our region by Sunday and Monday, according to
the latest weather models. As a result, moisture levels are
anticipated to increase again. The latest precipitable water
models show moisture levels rising to 2.0 to 2.3 inches, which is
above normal. Consequently, there will be an ongoing threat of
minor urban and small stream flooding across portions of the
islands, as well as ponding of water on roads and in poorly
drained areas. The potential for mudslides and unstable terrain
will persist, mainly Sunday through early next week, due to the
continued saturated soil conditions across much of the forecast
area.

From Monday afternoon through mid-week, expect winds to shift from
the north after the passage of the front, accompanied by a drier
and more stable air mass. A mid to upper-level ridge will
dominate, and precipitable water values should be below average.
As a result, minimal to no rainfall activity is expected, with
daytime temperatures ranging from the low to mid 80s in coastal
and urban areas, and in the low to mid 70s in higher elevations.
Minimum temperatures are forecast to range from the mid to upper
70s in lower elevations, and the 60s in higher areas.

&&

.AVIATION...

(06Z TAFS)

VFR conditions will prevail durg prd. Wdly SCT -SHRA/SHRA ovr
regional water and en route btw islands with few TSRA psbl ovr ATL
waters north of the local islands. VCSH at TJSJ/TISX/TISX and
east interior of PR with Mtn top obscr psbl due to passing
SHRA/Low cig til 13/13Z. Fm 13/17Z-13/22Z, locally and diurnally
induced SHRA and Isold TSRA psbl mainly across the Cordillera
Central which may briefly cause Mtn top obscr. Wnds calm to light
and vrbl...bcmg generally fm ESE 5-10 kts,with sea breeze
variations and occasionally hir gusts mainly with passing SHRA.

&&

.MARINE...

Calm to light and variable winds will prevail over the next few
days. Pulses of northerly swell will continue to reach the area
through this afternoon, maintaining hazardous seas for small craft
along the offshore and coastal Atlantic waters. Conditions are
expected to improve tonight into Thursday, but another swell is
anticipated at the end of the week, which may deteriorate marine
conditions once again.

&&

.BEACH FORECAST...

There is a high risk of rip currents through this afternoon along
the northern coast of Puerto Rico; from Rincón to Fajardo, as
well as in Culebra, Vieques, and the U.S. Virgin Islands (St.
Thomas and St. John). This is due to pulses of a fading northerly
swell spreading across the region. Additionally, large breaking
waves of 8 to 10 feet are expected along all northern coastal
areas of Puerto Rico. As a result, a High Surf Advisory remains in
effect until 6 PM AST this evening.

The risk of rip currents is forecast to decrease to moderate by
Thursday. However, another swell is anticipated for the end of
the week, which may again deteriorate marine and coastal
conditions. We encourage both residents and visitors to remain
vigilant and stay updated on the forecast if planning any beach
activities. For more details, please consult the Surf Zone
Forecast (SRFSJU).

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
545 AM AST Thu Nov 14 2024

.SYNOPSIS...
A building surface high pressure ridge across the west and southwest
Atlantic will moisture remnants along a stalled cold front east and
southward across the central Atlantic and north of the area respectively.
This moisture along the frontal boundary will gradually sag southward
across the region to maintain above normal moisture over the islands
through at least the early part of next week. Already saturated soils
from previous days rains along with locally and diurnally induced
convection will increase the risk of flooding, landslides and quick
river rises each day. Marine and coastal conditions are expected
to gradually improve today, however another northerly swell will arrive
and spread across the Atlantic waters,resulting in a deterioration
of the marine conditions once again.

&&

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

Overnight radar and satellite imagery indicated generally calm
conditions over land. Shower activity remained focused over the
Atlantic waters for most of the night, driven by a frontal boundary
positioned to the north. Some showers have since approached the
islands, with Culebra and the northern USVI receiving rain in the
last hour. Temperatures overnight ranged from the mid to upper 70s
along coastal and urban areas, and from the 60s to low 70s across
the mountain regions. Light and variable winds dominated.

The short-term forecast will be dominated by a humid pattern, with
an ongoing flood threat ranging from limited to elevated. Aloft, a
shortwave trough will enhance instability by promoting ventilation
today. At the surface, winds will remain light or calm due to the
approach of another frontal boundary. The latest precipitable water
models show moisture levels up to 2 inches, which is at the high end
of normal values. Moisture from the aforementioned frontal boundary
is expected to sink southward toward the region today and then stall
through the end of the week. As a result, early daily morning
showers are expected to affect parts of the northern coastal
sections of the islands, followed by afternoon convection due to
diurnal and local effects, especially over the central and eastern
interior of Puerto Rico. By Saturday, a polar trough will start to
swing across the western Atlantic and its associated cold front
will start to approach our region, while a surface high-pressure
system over the Southeastern U.S. will begin to move across the
western Atlantic. This will be accompanied by a ridging pattern
over the eastern and central Atlantic, which will keep our region
under a southerly wind flow. This flow will maintain moisture
pooling, resulting in moist and variable conditions across the
islands. Consequently, there will be an ongoing threat of minor
urban and small stream flooding across portions of the islands, as
well as ponding of water on roads and in poorly drained areas.
The potential for mudslides and unstable terrain will also persist
due to continued saturated soil conditions across much of the
forecast area. Residents and visitors are encouraged to continue
monitor the forecast and any advisory or warning for their area.

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

Surface high pressure will continue to build across the west and
southwest Atlantic. This will aid in pushing the stalled cold
front north of the region farther southwards across the area along
with frontal boundary and associated plume of moisture. This pattern
will initially maintain light and variable winds through early
Sunday, then become more north to northeasterly by the early part
of the following workweek. This light wind flow will maintain
tropical moisture pooling, resulting in moist and variable conditions
across the islands. With a light southerly low level winds,temperatures
are expected to rise a few degrees, reaching the upper 80s to near
90 degrees in some of the urban areas and lower elevations, Local
and diurnal effects will likely lead to afternoon convection and
isolated thunderstorms especially across the interior and northwest
sections of Puerto Rico. The U.S. Virgin Islands will also experience
episodes of showers and Isolated thunderstorms at least through early
Monday with a gradually drying trend and more seasonal conditions expected
for the rest of the period, as a strong high pressure ridge and more
northerly winds will prevail.

In the upper levels, at least through Sunday the polar trough will
sweep across the Atlantic, and as mentioned the associated cold
front is forecast to eventually cross our region Sunday into Monday
based on recent model guidance. As a result, moisture content and
precipitable water levels are anticipated to remain high ranging
between 2.0 to 2.3 inches which is above normal through Monday.
Consequently, there will be an ongoing threat of minor urban and
small stream flooding across portions of the islands, as well as
ponding of water on roads and in poorly drained areas. The potential
for mudslides and unstable terrain will persist, Sunday through
at least early Monday, due to the continued saturated soil conditions
across much of the forecast area.

By Monday afternoon through the rest of the period, expect winds
to shift from the north after the passage of the frontal moisture,
accompanied by a drier and more stable air mass. A mid to upper-
level ridge will then dominate, and precipitable water values should
be diminish significantly to near or below average. As a result, minimal
to no rainfall activity is expected, with daytime temperatures ranging
from the low to mid 80s in coastal and urban areas, and in the low
to mid 70s in higher elevations. Minimum temperatures are forecast
to range from the mid to upper 70s in lower elevations, and the
60s in higher areas.

&&

.AVIATION...

VFR conditions across most of the TAF sites are expected to persist
through the next few hours. A cold front to the north will bring cloudiness,
showers, and isolated thunderstorms today, especially after 15Z. This
could result in intermittent MVFR conditions and mountain obscurations.
Winds will remain generally VRB and less than 10kt with the exception
of any moderate to heavy rain development.

&&

.MARINE...
Light and variable winds will prevail over the next few days.
Pulses of a fading northerly swell will continue to reach the area
through this evening while conditions gradually improve making
conditions more favorable for small craft operators. However,
these conditions will be short-lived as another northerly swell
will arrive e and spread across the local Atlantic leading to a
deterioration of the marine conditions on Friday and into the
weekend.

&&

.BEACH FORECAST...

A moderate risk of rip currents will be in effect for the northern
coastline of Puerto Rico, as well as Culebra until later tonight.
Thereafter beaches of Aguada, Rincon and the northern USVI will
become moderate to high risk of rip currents through Saturday,as
conditions along the north and east facing beach are forecast to
deteriorate when another northerly swell is anticipated.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
438 AM AST Fri Nov 15 2024

.SYNOPSIS...
A cold front near the area will continue to produce showers across
the islands. Another frontal boundary is expected to reach the
islands on Saturday and Sunday, followed by drier conditions for
the first half of the next workweek. Marine and beach conditions
will be hazardous through early next week as a northerly swell
arrives.


&&

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

Overnight radar and satellite imagery indicated generally calm
conditions over land, with shower activity associated with a frontal
boundary focused over the Atlantic waters for most of the night.
Based on radar estimates, San Juan area and eastern Puerto Rico had
around 0.2 to 0.10 oh rain. Temperatures overnight ranged from the
mid to upper 70s along coastal and urban areas, and from the 60s to
low 70s across the mountainous regions. Light and variable winds
dominated the region.

The unstable and wet pattern will persist throughout the short-term
forecast. For today, light and variable winds ahead of the stalled
frontal boundary to the north will prevail across our region. This
boundary will maintain above-normal precipitable water values,
around 2 inches. Even most of the rain activity will stay over the
Atlantic waters, morning showers are expected to continue and move
inland, primarily over the northern coast of Puerto Rico, eastern
municipalities, and surrounding islands. Afternoon showers and
isolated thunderstorms, driven by diurnal and local effects, will
spread into the interior and coastal sectors later today.

Tonight, a change in the wind pattern is expected. Winds will shift
to a southerly component, driven by surface ridging over the
northeastern Atlantic. The current frontal boundary and its
associated moisture field are expected to be pushed to the north.
This will enhance showers Saturday morning across southwestern and
western Puerto Rico. Additionally, a polar trough over the Northeast
U.S. and its associated cold front will begin to move into the
western Atlantic waters.

By Saturday, strong high pressure building across the western
Atlantic will continue to push the cold front toward the Caribbean.
According to the latest model guidance, the front is expected to
cross our region by Saturday night into Sunday. Sufficient moisture
and instability will remain in place, making Sunday the most active
day of this period. After the front passes, a much drier air mass
will dominate the region, leading to a more stable weather pattern
starting Sunday night.

Overall, the flood threat will remain elevated through Sunday across
the islands with the risk to observe urban and small stream flooding
and quick river rises. The potential for mudslides and unstable
terrain will also persist due to continued saturated soil conditions
across much of the forecast area. Residents and visitors are
encouraged to continue monitor the forecast and any advisory or
warning for their area.

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

After the cold front passes through the islands, a cooler and
drier air mass will filter into the region, with temperatures
dropping a little below normal. A mid to upper level ridge will
roll from the southeastern United States into the western
Caribbean. This feature will maintain a trade wind cap inversion
around 850 mb, with all the low level moisture trapped below this
level. During the first half of the workweek, the probability of
precipitation will be generally low, except just southeast of
Saint Croix, where the remnants of the cold front will linger.

As the high pressure system migrates toward the east and moves
into the central Atlantic, the winds will shift from the southeast
on Thursday and from the south on Friday. This will once again
pull moisture from the Caribbean into the local islands,
increasing the potential for some showers. Temperatures will
bounce back, and highs are expected to reach the upper 80s and low
90s once again, especially for the low-elevated and urban areas.


&&

.AVIATION...
(06Z TAFS)

VFR conditions across most of the TAF sites are expected to persist
through the next few hours. A cold front stalled to the north will
keep cloudiness, showers, and isolated thunderstorms this morning,
TJSJ and TIST having the best chance to observe rain. Afternoon
showers and isolated thunderstorms, driven by diurnal and local
effects, will spread into the interior and coastal sectors after
18Z. This could result in intermittent MVFR conditions and mountain
obscurations. Winds will remain generally with typical variations
and light, less than 10kt with the exception of any moderate to
heavy rain development. A more southerly component is expected to
develop tonight.

&&

.MARINE...
Gentle to moderate and variable winds will prevail over the next few
days. Marine conditions will become favorable for small craft
starting on Friday morning as moisture remnants along a cold frontal
boundary sink southward across the region. This will increase the
chance for showers and isolated thunderstorms across the regional
waters and passages. Pulses of a northerly swells are expected to
arrive and create hazardous seas today, stretching into the weekend.


&&

.BEACH FORECAST...
Pulses from a northerly swell will maintain a high rip current
risk for the beaches of northern Puerto Rico from Rincon to
Fajardo, Culebra, and Saint Thomas and St. John. This conditions
could deteriorate further tomorrow and Sunday, with higher
breaking waves anticipated.

Breaking waves will be lower in the beaches of the Caribbean Sea
in southern Puerto Rico, where the rip current risk is low.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
509 AM AST Sat Nov 16 2024

.SYNOPSIS...

A frontal boundary north of the area, followed by another
approaching cold front tonight, will maintain wet and unstable
conditions and will continue to promote showers and thunderstorms
across the local islands during the weekend. After the approaching
cold front crosses the region tomorrow, a drier and cooler air
mass will be reach the area by Monday and linger through midweek.
A northerly swell will continue to reach the regional waters,
deteriorating marine and coastal conditions through Monday. Small
Craft Advisories, High Surf Advisories and High Risk of Rip
Currents are in effect.

&&

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

Strong thunderstorms were observed across the western offshore
Atlantic and over the Caribbean waters. These storms moved across
southwest and southeast Puerto Rico, but the heaviest accumulations
stayed over the waters. For Saint Thomas and Saint John, the storms
managed to move inland, with heavy downpours, lighting and
accumulations around one inch.

A stationary front is causing these showers, and its remnants
will maintain high moisture levels across the region. There is
also a trough at all levels, with its axis west of the region.
This has caused the winds to shift from the southwest today,
although light. With winds coming from this direction, the morning
showers are expected for western and southwestern Puerto Rico,
and for the vicinity of the Virgin Islands. In the afternoon, with
enough instability and local effects, the heavy rain is
anticipated for the San Juan metro area and northeastern Puerto
Rico. Urban and small flooding and water surges along rivers can
be expected with this activity.

Another frontal boundary is expected to make its way into the region
later tonight and tomorrow, with more showers and thunderstorms in
the forecast. The winds will remain mostly light and from the west,
so while the rain will be moving from the Mona Channel and the
Caribbean into Puerto Rico, the afternoon activity should develop in
the eastern half of Puerto Rico, progressing toward Vieques,
Culebra and the Virgin Islands. Once again, the risk for urban and
small stream flooding will be elevated.

Changes in the pattern are in store for the start of the workweek.
As the frontal boundary crosses the region, the air mass will dry
out and winds will shift from the north. Conditions will become
unfavorable for strong showers to develop and generally fair weather
will persist. Additionally, 925 mb temperatures will drop below
normal, so cooler temperatures are in the forecast.

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

A decrease in precipitable water values (PWAT) is forecast to
continue by the start of the long term forecast period. Current
model guidance has PWAT values of 0.9 to 1.2 inches, well below to
below normal values for this time of the year. This is due to a
cooler and drier air mass filtering into the region under northerly
flow behind the frontal boundary mentioned at the end of the short
term period. 850mb to 700mb relative humidity and 925mb temperatures
are forecast to be below normal to start the long term period. A mid
to upper level ridge will move in from the southeastern United
States into the western Caribbean, maintaining a trade wind cap
inversion around 850 mb, with all the low level moisture trapped
below this level. Through Wednesday, generally low probability of
precipitation (POP) will remain, except just southeast of Saint
Croix, where remnant moisture of the cold front will linger.

PWAT values will climb back up once winds veer to become more
easterly on Thursday and gain a southerly component on Friday. This
change in wind direction will be due to a surface high moving from
the east to central Atlantic. Moisture will be brought in from the
east and south, increasing the potential for showers and afternoon
convection. Temperatures will once again reach the upper 80s to low
90s across lower elevations of the islands.

&&

.AVIATION...

(06Z TAFS)

SHRA and TSRA will persist across the Caribbean waters, reaching
TJPS and the USVI terminals at times. After 17Z,additional
activity is also expected near TJSJ. Periods of reduced VIS and
low ceilings are anticipated. The winds are from the SW through
13-15Z, then shifting from the west through the forecast period.
Speeds are at 4-10 kts, with stronger gusts near thunderstorms.

&&

.MARINE...

Gentle to moderate westerly winds will prevail today and tonight,
becoming northerly tomorrow and northeasterly on Monday. Marine
conditions will be unfavorable for small craft through Monday
due to pulses of northerly swells. A frontal boundary north of the
region and associated moisture, will increase the chance for showers
and isolated thunderstorms across the regional waters and
passages. Small Craft Advisories are in effect today for the
coastal and offshore Atlantic waters and local passages. After 6
PM AST and through noon AST on Monday, Small Craft Advisories for
the coastal and offshore Atlantic waters will remain.

&&

.BEACH FORECAST...

Pulses of northerly swell will maintain deteriorated coastal
conditions, mainly across Atlantic facing coastlines, and they
continue to be detected by buoy 41043 (around 174 nm N-NNE of San
Juan) and buoy 41044 (around 460 nm ENE of San Juan). A High Surf
Advisory will be in effect through 6 AM AST Sunday for the
northern coastline of Puerto Rico from Aguadilla to Fajardo, as
well as for Culebra, St. Thomas and St. John. A High Surf Advisory
is also in effect for the beaches of Aguada and Rincon through 6
PM AST this evening. A High Risk of Rip Currents is in effect for
the northern coastline of Puerto Rico from Rincon to Fajardo,
including Culebra, as well as for St. Thomas and St. John through
6 PM AST Monday. A High Risk of Rip Currents is also in effect for
Vieques through 6 PM AST this evening. For more information,
please refer to the SRFSJU and CFWSJU.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
446 AM AST Sun Nov 17 2024

.SYNOPSIS...

A cold front north of the area, will maintain wet and unsettled
conditions and will continue to promote showers and thunderstorms
today as it crosses the islands. After the frontal passage, a
drier and cooler air mass will reach the area by Monday and linger
through midweek. This will bring "el friito navideno"! A
northerly swell will continue to reach the regional waters,
deteriorating marine and coastal conditions through tomorrow.
Small Craft Advisories, Coastal Flood Advisories, High Surf
Advisories and High Risk of Rip Currents are in effect.

&&

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

The evening hours were very active across eastern Puerto Rico, where
flash flooding, mudslides, and rivers reaching flood stages were
observed. Rainfall accumulations ranged from 3 to 6 inches, with the
highest accumulations in Humacao. Later at night, the heaviest
activity moved over Saint Croix, with heavy rain and reduced
visibilities. Additionally, new showers developed over the Atlantic
and Caribbean waters, and are expected to reach the Virgin Islands,
northern and western Puerto Rico.

Another cold front is analyzed north of the islands today, and it is
expected to push down into the area today. The high resolution and
global models show more showers and thunderstorms developing today,
mainly in the afternoon and evening hours for northern, western, and
eastern Puerto Rico, as well as for the Virgin Islands. With rivers
running high and soils saturated, the risk of flooding will be
elevated (locally high, especially across eastern Puerto Rico). The
thunderstorms may also bring gusty winds and lightning activity.

The rain will gradually taper off in the overnight hours, giving way
to a drier and cooler pattern. A high pressure system will roll from
the west into the Bahamas, with drier air establishing above 850 mb.
During the first couple of days of the workweek, generally fair
weather will prevail. The only exception will be the vicinity of
Saint Croix, where the remnants of the front will hang around. Also,
temperatures will cool down below the climatological value for a
change, so it will feel cooler too.


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

Below normal precipitable water values (PWAT) are forecast to
continue by midweek. Current model guidance has PWAT values of 0.9
to 1.2 inches, well below to below normal values for this time of
the year. This is due to a cooler and drier air mass filtering
into the region under northerly flow behind the frontal boundary
mentioned at the end of the short term period. Mid to upper level
ridging will move in from the southeastern U.S. into the western
Caribbean, maintaining a trade wind cap inversion around 850 mb,
with all the low level moisture trapped below this level. This low
level moisture as well as 925mb temperatures are forecast to be
below normal to start the period. Generally low probability of
precipitation (POP) will remain, except just southeast of Saint
Croix, where remnant moisture of the cold front will linger.

Increasing moisture will then be experienced Thursday through
Saturday as winds veer to become more easterly on Thursday and
gain a southerly component Friday and Saturday. This change in
wind direction will be due to a surface high moving from the east
to central Atlantic. A moisture plume will be brought in from the
east and south, increasing the potential for showers and
afternoon convection. Model guidance suggest that the trade cap
will not be present by late Friday and Saturday leaving high
relative humidities at all levels. PWAT values are forecast to be
at around 2.25 in. Highs will once again reach the upper 80s to
low 90s across lower elevations of the islands.

&&

.AVIATION...

(06Z TAFS)

Mainly VFR conditions expected to prevail before 15Z today. Then,
SHRA and TSRA will will develop, bringing periods of reduced VIS and
low ceilings for TJSJ and the USVI terminals. After 18Z, this
activity could spread into TJBQ and TJPS as well. The winds will be
from the north at 5-8 kts.

&&

.MARINE...

Gentle to moderate northerly winds will prevail through late
Wednesday when easterly winds return. Marine conditions will be
unfavorable for small craft through tomorrow due to pulses of
northerly swells. A cold front north of the region and associated
moisture, is forecast to move through the islands today. This will
increase the chance for showers and scattered thunderstorms across
the regional waters and passages. A drier pattern is forecast to
start the workweek.

&&

.BEACH FORECAST...

A long period northerly swell will create hazardous coastal
conditions along the north-facing beaches of PR and the US Virgin
Islands through at least tomorrow, Monday. The exposed Atlantic
coastline will be impacted by breaking waves between 8 and 15 feet.
Additionally, the full moon phase will exacerbate the high tides,
where isolated coastal flooding is expected along the most
vulnerable beaches of northern PR through at least noon on Sunday.
The coastal hazards that will impact the north-facing beaches are
life-threatening rip currents and breaking waves.

&&

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
426 AM AST Mon Nov 18 2024

.SYNOPSIS...
Marine and coastal conditions will remain deteriorated today as a
northerly swell continues to invade the Atlantic waters. This
conditions should improve by this evening or tomorrow. Drier and
cooler air moved in, bringing fair weather through the first half
of the workweek. Showers will increase once again after Thursday.

&&

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

Current Satellite derived precipitable water (PWAT) values confirms
notably drier air approaching the islands from the north, behind the
cold front that moved over the region yesterday. By 400 AM, PWAT
values over Puerto Rico were around 1.2 to 1.45 in. At the same
time, PWAT over Vieques, Culebra and the northern USVI were somewhat
higher (1.6 to 1.7 in) while over St. Croix it was around 1.85 in.
Since midnight, lingering light showers continued to affect the
eastern third of Puerto Rico, and sectors of the local islands. This
activity has been gradually decreasing in coverage throughout the
overnight hours. The frontal boundary and associated showers and
thunderstorms are already south of St. Croix. Reported overnight
lows were in the low to upper 60s over higher elevations of Puerto
Rico and in the mid 70s to around 80 across lower elevations of the
islands.

Cooler and drier air will continue to filter into the islands under
northerly flow through Wednesday. Current model guidance has PWAT
values of 0.9 to 1.3 inches, well below to below normal values for
this time of the year. Mid to upper level ridging will move in from
the southeastern U.S. into the western Caribbean, maintaining a
trade wind cap inversion around 850 mb, with all the low level
moisture trapped below this level. Low level moisture as well as
925mb temperatures are forecast to be below normal during the
period. Generally low probability of precipitation (POP) will
remain, except during posible afternoon convection and also just
southeast of Saint Croix, where remnant moisture from the front will
linger. 500 mb temperatures will also warm up, further diminishing
deep convection activity possibilities. Surface winds will be
generally northeasterly, with an easterly component starting to
further dominate by late Wednesday, as a surface high gradually
moves in from our northwest. Generally stable conditions will
prevail during most of the period with temperatures cooling down to
below climatological values.


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

The weather pattern will shift to a wetter one once again. As a
surface to mid-level high builds west over the eastern Atlantic,
the wind flow will shift will gain a more southerly component,
pulling moisture from the Caribbean into the region. So far, the
global guidance indicate that the bulk of the moisture will move
closer to the Dominican Republic, but precipitable water should
still go above normal from Thursday through Saturday. This will
bring an increase in showers and thunderstorms for the islands,
increasing the risk for flooding. Also, under a deep-layered
southerly flow, temperatures will soar once again, and the warmer
than normal heat will return, except on areas where the cloud deck
remains thick enough. For Sunday, a pocket of drier air will move
in, giving the islands a break from the wet pattern, but it looks
like another surge of moisture will approach from the east early
next week, with another round of rain for the eastern Caribbean.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions are forecast to prevail across the terminals.
VCSH will linger during the early morning hours and at times will be
brought in by northeasterly flow. After 18Z, convective VCSH
possibly affecting TJPS. Low level NE winds will be up to 12 kts
with higher gusts and sea breeze variations.

&&

.MARINE...
Gentle to moderate northerly winds will prevail through late Wednesday
when easterly winds return. Marine conditions will be unfavorable for
small craft through today due to additional pulses of northerly
swells. The remnants of a cold front just south of the region will
bring additional showers and isolated thunderstorms to the Caribbean
waters.

&&

.BEACH FORECAST...
The local buoys still show seas 6 to 8 feet across northern Puerto
Rico, with a period of 12 to 13 seconds. This will result in
dangerous high surf due to breaking waves above 10 feet. For
Vieques, Culebra, Saint Thomas and Saint John, the rip current
risk is high, and moderate is Saint Thomas.

Minor coastal flooding and beach erosion is also possible in the
most vulnerable beaches of northern Puerto Rico. The high tide
in San Juan will be at 11:13 AM AST, at 2.06 ft.

Conditions should improve by the evening or tomorrow, but still
with a moderate rip current risk in effect.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
351 AM AST Tue Nov 19 2024

.SYNOPSIS...
Cooler than normal temperatures and dry conditions will persist
at least until early Thursday. Then, showers and thunderstorms
will increase for the end of the workweek and early next week.
Marine conditions have improve, but across the beaches, the rip of
rip currents remain moderate.

&&

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

It was a cool night over the islands with reported overnight lows
were in the low to mid 60s at higher elevations of Puerto Rico, in
the upper 60s to mid 70s at lower elevations of Puerto Rico, and in
the mid 70s to around 80 at the USVI. Since midnight, only light
showers have been moving over the north and northwestern waters.
Current satellite derived precipitable water (PWAT) values shows dry
air over the region. During the overnight hours, PWAT values over
Puerto Rico were around 1 to 1.2 inches, well below normal to below
normal, increasing eastward. Below normal PWAT values were also
observed over other regions, Vieques, Culebra and the northern USVI
saw between 1.27 to 1.29 inches, and St. Croix saw around 1.35 in.

Cool and dry air will continue to move over the islands under
northerly flow through Wednesday. Current model guidance has PWAT
values of 0.9 to 1.3 inches through Wednesday, well below to below
normal values for this time of the year. Mid to upper level ridging
will maintain a trade wind cap inversion around 850 mb, with all the
low level moisture trapped below this level. Low level moisture
itself, as well as 925mb temperatures, are forecast to be below
normal through most of the period but beginning to climb back up on
Thursday. Generally low probability of precipitation (POP) will
remain through Wednesday, with some showers moving in at times from
the waters towards windward sections. 500 mb temperatures will be
warm, further diminishing deep convective activity possibilities,
however local effects can help produce limited afternoon convection
over the interior. Generally stable conditions will prevail during
most of the period with temperatures cooling down to below
climatological values. Highs will be in the the mid 80s across most
coastal areas of the islands, except in southern PR where it can
reach the low 90s. Cool lows similar to last night will also
continue. Surface winds will be generally northeasterly, becoming
more easterly on late Wednesday and Thursday, as a surface high
gradually moves in from our northwest. Increasing moisture will then
be experienced Thursday with PWAT values climbing back to low end
normal values. The change in wind will bring in a moisture plume
from the east and south, increasing the potential for showers and
setting the stage for a wetter long term period.

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

A high pressure system over the eastern Atlantic and a polar
trough exiting the eastern coast of the United States will switch
the winds from the south for the end of the week. The pressure
gradient will weaken too, meaning that the wind flow will be
light. Under this flow, moisture will be pulled from the Caribbean
Sea into the islands, increasing the potential for showers and
thunderstorms. This will elevate the risk of flooding for the
islands through the weekend. Then, early next week, the ridge will
rebuild, but precipitable water values will remain above normal.
The trade winds will recover too, coming from the east around 15
knots. Under this flow, patches of low-level clouds will still
reach the islands, with passing showers activity for eastern
Puerto Rico and the Virgin Islands.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions are forecast to prevail across the terminals.
VCSH will be brought in by northeasterly flow, particularly towards
TJBQ to start the morning. After 18Z, convective VCSH can also
possibly affecting TJPS. Below FL050, NE winds will be up to around
10 kts with higher gusts and sea breeze variations.

&&

.MARINE...
Gentle to moderate northerly winds will prevail through late Wednesday
when easterly winds return. Another pulse of the northerly swell will
arrive tomorrow, but conditions are likely to remain below small
craft advisory criteria. Another small long-period northerly swell is
expected for the weekend.

&&

.BEACH FORECAST...
Coastal conditions have improve across Puerto Rico and the Virgin
Islands, but the risk of rip currents continue to be moderate.
There is another pulse of northerly swell that could arrive
tomorrow, increasing the risk to high again.

[cycloneye]

AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
540 AM AST Wed Nov 20 2024

.SYNOPSIS...High pressure will form in the western tropical
Atlantic during the latter part of the week as a distant low pulls
northeast and the cool air behind the front warms. Drier weather
with only a few showers are expected through Friday then better
moisture on south to southeast flow will return to the area
increasing showers and the chance of thunderstorms.

&&

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

During the overnight hours, satellite derived precipitable water
(PWAT) values over Puerto Rico were around 1.09 to 1.2 inches, well
below normal to below normal, with the higher values over eastern
PR. Below normal PWAT values were also observed over the USVI with
up to 1.30 to 1.35 in. Since midnight, cold air advection promoted
light to locally moderate showers under NE winds, mainly across
northern and eastern Puerto Rico, Vieques, St. Thomas and St. Croix.
These showers left, a radar estimated, 0.20 to 0.25 inches over
Vieques, eastern St. Croix and isolated areas of NE PR. Reported
lows were in the low to mid 60s at higher elevations of Puerto Rico
and in the mid 70s to around 80 over lower elevations of the islands.

Current model guidance has PWAT values of 0.9 to 1.3 inches over the
islands through Thursday, well below to below normal values for this
time of the year. Northeasterly flow will continue today, bringing
cool and relatively dry air over the region. Advective showers will
still move in over windward sectors at times. A polar trough will
exit the eastern coast of the U.S while a surface high will
gradually move over the central Atlantic from our northwest,
promoting winds to gradually veer to become more easterly tonight,
southeasterly tomorrow afternoon, and then southerly by Friday.
Increasing moisture will then be experienced Friday with PWAT values
climbing back to low end normal values. The change in wind will
bring in a moisture plume from the east and south, increasing the
potential for showers and setting the stage for a wetter long term
period. The pressure gradient will be weak, promoting light wind
flow. By Friday, southerly flow will pull moisture from the
Caribbean Sea into the islands, increasing PWAT values back to
around and above 2 inches in the afternoon/evening. Mid to upper
level ridging will maintain a trade wind cap inversion around 800
mb, with all the low level moisture trapped below this level,
through Friday afternoon when deep moisture moves into the region.
Likewise low level moisture itself, as well as 925mb
temperatures, are forecast to be below normal until Friday when
they climb back up. Before Friday, 500 mb temperatures will be
pretty warm, diminishing deep convective activity possibilities,
however local effects can help produce limited afternoon
convection over the interior. Cold air advection will also promote
showers over northern and eastern regions. Highs will be in the
the mid to upper 80s today across most coastal areas of the
islands, except in southern PR where it can reach the low 90s.
Limited to elevated excessive rainfall risks and and an increased
potential for thunderstorms will be present for the second half of
the workweek, especially on Friday with all of the columnar
moisture over the region. This wet pattern will continue into the
long term forecast period.

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

High pressure at upper levels dominates the long period despite
the passage of an upper level trough saturday evening well to the
north of the area. The associated southwesterly jet stream will
likely never get past Cuba. At mid levels high pressure becomes
entrenched about 1000 miles east northeast of San Juan, Puerto
Rico and moves very little. As the flow around this high is from
the south modest moisture will be brought up out of the Caribbean
during the period. Peak moisture will be seen late Sunday night
and Monday morning. At the surface high pressure northeast of the
area--much where the mid level high is also--keeps flow southerly.
A weak wave passing to the west over the Caribbean begins to
amplify south of Jamaica and flow turns southeasterly for the
remainder of the period. While this does bring in some moisture,
flow is never particularly moist at any one level but precipitable
water values remain above two inches except for a 24 hour period
from early Tuesday to early Wednesday when air from the mid
Atlantic is brought back in around the high pressure east
northeast of the area. While the low pressure expected to form
over the Central Caribbean will not directly affect Puerto Rico
or the U.S. Virgin Islands, periods of showers will keep the area
wet. At this time this does not appear to generate expectations
for anything more than ponding of roads and some stream rises.

&&

.AVIATION...
(06Z TAFS)

Mainly VFR conditions are forecast to prevail across the terminals.
VCSH will be brought in by northeasterly flow at times. After 18Z,
convective VCSH also possibly affecting TJPS. Below FL050, NE winds
will be up to around 12 kts with higher gusts and sea breeze
variations.

&&

.MARINE...Seas were rising at the outer buoy (41043) and these
swell were about 5 hours away from Puerto Rico's northern coast
and Culebra, however seas have leveled off for the moment so, for
now, seas of no more than 5-6 feet in areas exposed to northerly
swell are expected through Sunday. Another swell will move in on
Monday that may bring small craft conditions.

&&

.BEACH FORECAST...There is a high risk of rip currents tonight
for the San Juan zone, the Fajardo Zone, and Culebra. Otherwise
moderate or low risk of rip currents will be found until Sunday
night. Then, swell from beyond the Anegada Passage will bring a
high risk to Saint Croix and later to northwest and north central
Puerto Rico on Tuesday.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
536 AM AST Thu Nov 21 2024

.SYNOPSIS...Some moisture pushed into the northeast corner of the
forecast area last night and showers continued over the local
Atlantic waters, otherwise the atmosphere has been relatively dry
with a few heat-driven showers in the afternoon. Moisture will
move into the area on Friday morning bringing increased showers
and thunderstorms to the area. A northwesterly swell will increase
the rip current risk on Sunday. Except for a dry slot that crosses
Monday night conditions will remain mostly wet after this Friday.

&&

.SHORT TERM...Thursday through Saturday...

Relatively calm and quiet weather conditions prevailed during the
overnight hours across the islands. Satellite and doppler radar
observations indicated isolated to scattered showers mostly over the
Atlantic waters with no significant impact over the region. Lows
were in the low to mid 60s in the Cordillera Central of Puerto
Rico and in the mid to upper 70s in the coastal and urban areas of
the islands. Winds were light and variable through most of the
night.

After the frontal passage in the previous days, dry and stable
conditions continued across the region. Today, mostly calm
weather will continue to prevail. Afternoon showers may develop
across the interior and northwestern Puerto Rico due to the
combination of daytime heating and local effects. However, no
significant rainfall accumulations are anticipated at this time.
By Friday, a polar trough is expected to exit the eastern coast of
the United Sates, while a surface high pressure located north of
the area continue to move eastwards toward the central Atlantic.
This pattern will cause the winds to veer and become southeast
today and then south on Friday. Therefore, an increase in
moisture content is expected through the upcoming weekend. The
latest precipitable water content analysis has values of up to 2.0
inches. This analysis suggests an increase in moisture content
that may result in shower activity through the rest of the short-
term period.

Daytime temperatures will remain in the mid to upper 80s along the
coastal and urban areas of Puerto Rico and the U.S. Virgin Islands,
and in the upper 70s to low 80s in the Cordillera Central of Puerto
Rico. Minimum temperatures will drop to the low to mid 60s in the
higher elevations, and will remain in the 70s for the rest of the
area.

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

At upper levels, the sub-tropical jet between Florida and Haiti
will join the polar jet well north of the local area, but will be
unable to come much closer to the area due to high pressure that
stretches from the Central Caribbean to the tropical Atlantic
along 20 north which will drift a little south during the period.
A decaying wave will approach the area and cross the Windward
Islands from the east early Sunday morning to bring additional
moisture to the area. This moisture will move quickly past the
forecast area to the south and feed the developing north-south
trough north of Panama while pulling in drier air in from the
east over us on Monday. As the trough develops a low over
Jamaica, winds will become more southerly and bring more moisture
from the southeast Caribbean for continued shower activity.

500 mb temperatures will be mostly minus 5 to minus 6 during the
period, so there will present a chance of thunderstorms--mainly
during the afternoons over Puerto Rico and over the local waters
at night. Although some local urban and small stream flooding
could develop, showers should move just fast enough to prevent
major river rises during the period. Nevertheless most areas will
have at least some rain each day.

&&

.AVIATION...
(06Z TAFs)

Mainly VFR conds are expected to prevail across all terminals
through the forecast period. Aftn SHRA may result in VCSH at
TJPS/TJBQ/TIST/TISX btw 21/16-23Z. VRB at less than 5 kts will
continue thru 21/14Z. Then, ESE winds at 10-15 kt with higher
gusts and sea breeze variations through 21/22Z.

&&

.MARINE...

Small craft advisories are still likely Sunday through Tuesday--
mainly in the Atlantic waters when seas become 7 feet or more.

&&

.BEACH FORECAST...

Conditions have improved considerably since yesterday allowing the
High surf advisory to be dropped. But the increasing swell from
the north northwest on Sunday will elevate the rip current risk to
high through at least Monday.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
535 AM AST Fri Nov 22 2024

.SYNOPSIS...

The drier weather is about to come to an end as a line of showers
now approaching the southern boundary of our forecast area signals
the entry of a moist air mass. Temperatures will rise a little
today and remain warm tomorrow, but additional showers will end
the warming trend. Showers and isolated thunderstorms are
indicated for most of the upcoming seven days.

&&

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

Another calm night was observed across the northeastern Caribbean
under clear to partly cloudy skies. Satellite and radar observations
indicated passing showers moving over eastern Puerto Rico, and over
the local Caribbean and Atlantic waters. These showers were moving
quickly, leaving minor accumulations over the area. Minimum
temperatures were in the mid to upper 70s along the coastal portions
of the islands, with few locations reaching the lower 80s.
Meanwhile, lows were in the mid 60s across the Cordillera Central.
Winds were light and gentle from the southeast.

Today, variable weather conditions will prevail as a broad moisture
field moves from the Caribbean waters into the local area. At the
low levels, a surface high pressure will continue to strengthen
over the Central Atlantic, promoting southeasterly winds. Meanwhile,
at the upper levels a polar trough is anticipated to exit the
eastern coast of the U.S. today and will continue to move
eastwards for the next few days. As both of these features
migrate in the Atlantic, abundant tropical moisture will move
into the area promoting the development of showers and isolated
thunderstorms across the islands. The latest precipitable water
content analysis for Saturday has values between 1.7 to 2.0
inches. By Sunday, winds will shift and become from the east,
bringing additional moisture from a perturbation east of the
islands.

Prevailing winds from the southeast in combination with abundant
moisture will result in warm temperatures over the next few days.
Daytime temperatures will remain in the mid to upper 80s along the
coastal and urban areas of Puerto Rico and the U.S. Virgin Islands,
and in the upper 70s to low 80s in the Cordillera Central of Puerto
Rico. Minimum temperature will drop to the low to mid 60s in the
higher elevations, and will remain in the 70s for the rest of the
area.

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

At upper levels, the sub-tropical jet over Cuba will slide just
south of the polar jet well north of the Leeward Islands, This
sub-tropical jet which will more or less coincide with the
location of a cold front will be unable to come much closer to
the area due to high pressure that stretches from the Central
Caribbean to the tropical Atlantic along 20 north. The upper level
high will drift a little south during the period.

A perturbation in the lower levels mentioned above will approach
the area and cross the Windward Islands from the east early Sunday
morning to bring additional moisture to the area. This moisture
will move quickly past the forecast area to the south and feed the
developing north-south trough north of Panama while pulling drier
air in from the east over us on Monday. As the trough develops a
low over the eastern tip of Jamaica, winds will become more
southerly and bring more moisture from the southeast Caribbean for
continued shower activity. Then on Thursday and Friday as the low
near Jamaica extends a trough to the north northeast, a trough
will brush the northern part of our forecast area as an anti-
cyclonic eddy forms off the tip of Cabo Rojo, sustaining the
modest flow of moisture across the islands.

500 mb temperatures will be mostly minus 5 to minus 6 during the
period, so there will be a chance of thunderstorms--mainly during
the afternoons over Puerto Rico and over the local waters at
night. Although some local urban and small stream flooding could
develop, showers should move just fast enough to prevent major
river rises during the period. Nevertheless most areas will have
at least some rain each day.

&&

.AVIATION...
(06 TAFs)

Mainly VFR conds are expected to prevail across all terminals during
the next 24 hrs. Aftn SHRA may result in VCSH across all the
terminals in PR and the USVI thru 22/23Z. VRB winds will continue
thru 22/14Z, then shifting and prevailing from the SE btw 8-10 kts
with land and sea breeze variations thru 22/22Z.

&&

.MARINE...Seas of 4 to 5 feet will continue in the Atlantic with
mostly northerly swell. With seas of less than 2 feet in the
shadows of the islands. Another northwest to north swell will
enter the area on Sunday and slowly decay the following Thursday
and Friday, but in the meantime small craft advisories will likely
be needed for the Atlantic waters.

&&

.BEACH FORECAST...Moderate rip current risk will prevail along the
coasts exposed to the northerly swell, but on Sunday the risk will
become high as a new swell train descends onto the northern
coasts.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Sat Nov 23 2024

.SYNOPSIS...

Shower and thunderstorm activity will continue to increase across
the local waters and portions of the islands through the rest of
the weekend. A long-period northerly swell will cause seas to
build to around 7 feet by Sunday, and promote life-threatening rip
currents along the northwest to northeastern beaches of the
islands. The high risk of rip currents will continue through much
of the workweek. Diurnally induced afternoon showers and
thunderstorms can be expected each day over portions of the
mountain ranges and western PR.


&&

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

Moisture moved into the area on Friday and spawned scattered to
numerous thunderstorms over the local waters that continued through
the night--mainly in the Mona Channel and more isolated in the outer
Atlantic waters. Winds over land were light and temperatures were
mostly in the 70s in the lower elevations and the 60s in the higher
elevations. Winds are southerly at lower levels due to high pressure
in the central Atlantic about 27 degrees north. Winds will become
more easterly Saturday evening as high pressure moves off the
southeast coast of the United States and joins the high in the
central Atlantic. A trough forming north of Panama will aid in the
backing wind shift. Peak moisture will occur on Sunday afternoon,
but as the easterly winds continue, drier air will be pulled across
the area--if only for a day.

At upper levels, the trough associated with a deep low over the New
England States will begin to retreat back to the northern Bahama
Islands and a ridge will form over the local area that extends into
the sub tropical Atlantic near 20 north. This will also aid in the
drying over the local area. Chief temperature variations will be due
to clouds and rain and wind direction rather than any change of air
mass.

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

A surface high will gradually build over the central Atlantic and
a broad surface low is expected to develop south of Jamaica early
in the fcst period. This will promote a moist south to southeasterly
wind flow across the local area throughout the workweek. However,
the best moisture content is expected to remain over the Hispaniola
and the Mona Passage. Regardless, the precipitable water content
is expected to range between 1.75 to around 2 inches from late Tuesday
through the end of the long term period. This moisture content in
combination with daytime heating and the sea breeze convergence
will cause afternoon shower and thunderstorm development over
portions of the interior and western PR. At upper levels, a polar
trough is expected to remain far north, and the sub-tropical jet
should remain northwest of the area as a ridge builds over the
eastern Caribbean for most of the period. In response the 500 mb
temperatures will increase by a degree or two, fluctuating between
-5 and -6 degrees Celsius, enough to support afternoon convection.

High temperatures are expected to range between the upper 80s and
low 90s in general across the urban areas and lower elevations of
the islands.


&&

.AVIATION...
(06Z TAFs)

VFR conditions will prevail for all TAF sites for most of the
period. However, SHRA/TSRA cont offshore and over wrn PR. Aft 23/15Z
Shra/TSRA will dvlp ovr PR and arnd the USVI with lcl MVFR conds and
mtn obscurations. Winds SE up to 12 knots with hir gusts nr
SHRA/TSRA. Maximum winds SSW 30 kts at FL285 and WSW 30 kts at FL410.


&&

.MARINE...

North to northwest swell will fill across the Atlantic waters and
passages later this weekend. Seas will gradually build to around
7 feet by Sunday night across the Atlantic waters and small craft
advisory conditions could last through Tuesday. Moderate to fresh
trades are expected early in the workweek.


&&

.BEACH FORECAST...

A moderate risk of rip currents will prevail today across most
northern beaches of Puerto Rico. A long-period north-northwest
swell will arrive later this weekend, increasing once again the
risk of rip currents to high from Sunday onwards. Life-threatening
rip currents are expected along the northwest to northeast coast
of Puerto Rico, including Culebra. High surf conditions are also
possible.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
509 AM AST Sun Nov 24 2024

.SYNOPSIS...

Abundant moisture associated with a weak tropical wave east of
the islands will increase the potential to observe showers and
isolated thunderstorms across the region today. A drying trend is
expected on Monday through Tuesday evening However, showers are
expected each afternoon across the northwestern portions of Puerto
Rico. A northerly swell will arrive later tonight, deteriorating
the local marine and coastal conditions through at least mid-
week.


&&

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

A weak tropical wave has been plodding westward across the Caribbean
sea, mostly southeast of the forecast area. This has brought showers
and thunderstorms to the local waters overnight with occasional
intrusions of showers and thunderstorms inland over eastern Puerto
Rico and Saint Croix. Thunderstorms also brought gusty winds up to
25 mph to Saint Croix. Temperatures were mild with lows so far
ranging from the lower 80s around the smaller islands and along the
windward coasts of Puerto Rico. Lows in the 60s were observed in the
higher elevations.

Moisture will continue to increase through early this evening
(25/01Z) and then a drying trend begins as local easterly flow
brings in drier air from the northern tropical Atlantic and the
tropical wave passes us to the south and joins a trough of low
pressure in the west central Caribbean that is deepening up through
the Windward Passage. This drying trend will continue through noon
on Tuesday. The easterly winds are being generated by a ridge that
extends from northern Florida in the U.S. to the Canary Islands and
will persist at least through Tuesday.

Upper levels are similarly trending toward more stable conditions as
high press aloft about 1100 miles east northeast of San Juan,
gradually ridges over the local area. Nevertheless, sufficient heat
and humidity will exist--especially over the western and interior
portions of Puerto Rico and the surrounding waters including around
the U.S. Virgin Islands such that showers and isolated thunderstorms
will be able to form each day.

LONG TERM...Wednesday through Sunday...

A building surface high pressure over the central Atlantic and a
broad surface low south of Hispaniola and Jamaica will be the
dominant weather features for the long-term period. The
aforementioned features will promote a southeasterly wind flow
through the end of the weekend. The latest precipitable water
content analysis (PWAT) has values of 1.80 to 2.00 inches from
Wednesday into late Saturday suggesting abundant moisture content to
remain over the islands. With the presence of the surface low west
of the region, the better moisture content will remain over portions
of the Dominican Republic. However, the wind will continue to bring
pulses of moisture over the islands and promoting the development
of showers and thunderstorms over the region each day. By the end
of the period, winds will shift from the east. Much drier air
will start to filter into the area, improving weather conditions
across the area until the middle of next week. Daytime
temperatures will stay in the upper 80s to low 90s across the
coastal and urban areas of the islands, and in the low to mid 80s
in the higher elevations.

&&

.AVIATION...
(06Z TAFs)

VFR conditions will prevail thru 24/1500Z except at TISX where
SHRA/TSRA will cause ocnl MVFR conds. SHRA/TSRA are movg into the FA
from the SE and will sprd ovr PR and the nrn USVI aft 24/15Z with
areas of MVFR/IFR and mtn obscurations. Winds are easterly 8-12 kts
with gusts of greater than 20 kts nr SHRA/TSRA. Some land/sea breeze
influences. Maximum winds SW-WSW 27-32 kts btwn FL425-460.

&&

.MARINE...

Showers and thunderstorms will continue to affect portions of the
local waters through early this week. Today,the winds are anticipated
to become gentle to moderate, while a long-period north to northwest
swell arrives. Conditions will become hazardous for small crafts
through the early or middle part of the workweek.

&&

.BEACH FORECAST...

Pulses from a northerly swell will begin to arrive into the
islands today, deteriorating the marine and coastal conditions. A
high rip current risk is en effect for the north- facing beaches
of Puerto Rico, Culebra, Saint Thomas and Saint John, and St.
Croix through mid- week. A moderate risk is in effect elsewhere.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
536 AM AST Mon Nov 25 2024

.SYNOPSIS...

Breezy conditions across coastal areas early in the period.
Locally induced afternoon convection is expected each day. A
wetter pattern is expected for the latter part of the workweek
into the weekend. A northerly swell will fill in today,
deteriorating the local marine and coastal conditions through at
least mid-week.

&&

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

Variably cloudy skies prevailed across Puerto Rico and the U.S.
Virgin Islands during the overnight hours. Localized showers
persisted over the northern and eastern coastal municipalities of
Puerto Rico, and across the U.S. Virgin Islands. Observed rainfall
amounts were from a tenth of an inch in St. Croix to near a quarter
of an inch over El Yunque area. Minimum temperatures were between
the upper 60s across the higher elevations to the upper 70s across
the lower elevations. The wind was from the east up to 10 mph, with
gusts up to 26 mph near showers.

A weak surface high pressure north of the region will strengthen
over the central Atlantic by Wednesday. A frontal boundary south of
the high is expected to remain mainly above 20N. Meanwhile, a broad
surface low is expected to build just south of Jamaica during the
short-term period. This will promote moderate to locally fresh
easterly trades across the region through at least Tuesday, with a
more southeasterly component on Wednesday as the high shifts over
the central Atlantic. Although moisture has increased over the area
during the early morning hours, the increasing trades will push the
best moisture content west of the area. However, the precipitable
water content is expected to range between 1.75 and 2.25 inches from
Tuesday through Wednesday. This moisture content in combination with
daytime heating and the sea breeze convergence will cause afternoon
shower and thunderstorm development over portions of the interior
and western PR. At upper levels, a polar trough is expected to
remain far north, and the sub-tropical jet should remain northwest
of the area as a ridge builds over the eastern Caribbean for most of
the period. In response the 500 mb temperatures will increase by a
degree or two, fluctuating between -5 and -6 degrees Celsius, enough
to support afternoon convection.

High temperatures are expected to range between the upper 80s and
low 90s in general across the urban areas and lower elevations of
the islands.

&&


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

A variable weather pattern is expected for the latter part of the
workweek into the weekend. A building surface high pressure over the
central Atlantic and a broad surface low south of Hispaniola and
Jamaica will maintain an east-southeasterly flow, bringing pulses of
moisture over the region. The latest model guidance suggests that
Precipitable Water (PWAT) values will gradually increase above the
climatological normal. Additionally, the Galvez-Davison Index
suggests deep convection activity, particularly on Saturday and
Sunday. The abundant moisture content and instability aloft will
promote moderate to heavy showers and thunderstorms through the
weekend and early next week, increasing the potential of flooding
over the eastern sections of Puerto Rico and the USVI in the morning
hours and the interior and western Puerto Rico in the afternoon.
Ponding of water on roads and poorly drained areas is very likely,
enhancing urban and small stream floods. Winds will shift from the
east, and patches of dry air will filter into the region by the end
of the forecast period.

&&

.AVIATION...

(06Z TAFs)

Mainly VFR conditions are expected to prevail across all terminals
during the next 24 hours. However, trade wind SHRA may cause brief
MVFR cigs across the USVI and eastern PR terminals thru 24/13z, and
afternoon SHRA with possible iso TSTMs can develop near the vcty of
TJBQ btw 24/16z-22z. E winds btw 15-20 knots with sea breeze
variations and stronger gusts aft 24/14z.

&&

.MARINE...

A frontal boundary extending from the windward passage into the
Atlantic Ocean north of PR and the USVI will induce a pre-frontal
trough near the islands, promoting shower activity across the local
waters and passages. A north northwesterly swell will gradually fill
today and deteriorate the local marine and coastal conditions
through at least mid-week. The frontal boundary will linger north of
the islands while a surface high pressure builds from the western
Atlantic to the central Atlantic, with moderate to locally fresh
trade winds.

&&

.BEACH FORECAST...

The risk of rip currents will remain high across the north-facing
beaches of Puerto Rico, including Vieques and Culebra, and across
the Virgin Islands through at least Tuesday afternoon. Another
long-period swell from the north will arrive later in the week,
so it is likely that the risk will have to be extended through the
end of the week. For a more detailed forecast, please refer to the
latest Surf Zone Forecast (SRFSJU) and the Coastal Hazard Message
(CFWSJU).

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
504 AM AST Wed Nov 27 2024

.SYNOPSIS...

Stable weather conditions will persist for the next few days,
with occasional passing shower across the windward sections
during the night and convective afternoon activity mainly over
western/northwestern PR. A wet and variable weather pattern is
expected throughout the weekend and early next week. Another long
period northeasterly swell will spread across the local waters
later tonight, increasing the risk of rip currents.

&&

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

An area of showers and thunderstorms moved over the Caribbean waters
during the night hours, reaching the southern and western coast of
Puerto Rico at times. Rainfall in the west was light, but heavier
accumulations were observed from Ponce to Arroyo. This patch of
moisture will gradually move toward the Mona Channel and the
Dominican Republic, with conditions improving in the morning
hours.

A high pressure centered well to the northeast of the Caribbean will
maintain the winds from the east southeast at speeds of 10 to 20 mph
through the end of the workweek. This high pressure extend into the
mid and upper levels of the atmosphere, meaning that conditions
aloft are not particularly favorable for strong showers and
thunderstorms in the region, as a trade wind cap inversion will
develop around 850 mb. Regardless, enough low level moisture should
result in passing showers moving in the vicinity of the Virgin
Islands and eastern Puerto Rico, with additional activity firing up
in the afternoon across the northwestern corner of Puerto Rico.
these showers may lead to ponding of water on roadways and low lying
areas, while localized heavy rain may also lead to minor urban and
small stream flooding. The pattern will be similar all week long,
including Thanksgiving Day, but by the end of the day on Friday, a
better defined easterly disturbance will approach, increasing the
frequency and intensity of the rainfall activity.

&&

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

The long-term forecast remains on track. Wetter and unsettled
weather conditions are anticipated during the weekend and the
beginning of the next workweek. A building high surface pressure in
the Central Atlantic and a broad low surface pressure south to
Jamaica will maintain a ESE wind flow, bringing pulses of
moisture into the region. The latest model guidance suggests above
climatological normal PWAT values from Saturday onwards.
Additionally, the cross-section shows high humidity content in the
700-500 mb layer. The Galvez-Davison Index suggests deep
convective activity, with high chances of isolated thunderstorms,
particularly on Saturday and Sunday. Latest model solutions show
a low pressure at 700 mb reaching the region on Friday into
Saturday, but uncertainty remains high. Available moisture,
diurnal heating, and local effects will promote shower activity,
particularly in the eastern sections of Puerto Rico during the
morning and west/northwestern sections of PR during the afternoon
each day. Rainfall accumulations in roads and urban areas could
enhance the potential of flooding from urban and small streams.
Temperatures will remain from the mid to high 80s to the low 90s
in urban and high-elevation areas, with limited risk of excessive
heat for the rest of the forecast period.

&&

.AVIATION...

(06Z TAFS)

Mainly VFR conditions expected to prevail. SHRA will continue around
the Caribbean waters and Mona Channel, but minimal impacts to
operations is anticipated. Additional SHRA expected to develop after
17Z for TJBQ, with brief periods of reduced VIS and low ceilings.
Winds will be from the ESE at 13-15 kts, with stronger gusts.

&&

.MARINE...

A surface high pressure will build over the central Atlantic during
the next few days, promoting moderate to locally fresh trade winds.
These trade winds will bring passing showers each day. Another long
period northeasterly swell will spread across the local waters
later tonight, deteriorating marine conditions across the local
waters and passages for the next few days.

&&

.BEACH FORECAST...

The rip current risk will remain moderate for most beaches and
coastal areas of PR and the USVI. However, the risk will increase
to high for the north-facing beaches of Puerto Rico, Culebra, and
the U.S. Virgin Islands as a long-period northeasterly swell
arrives later tonight deteriorating marine and coastal conditions
for the next few days. For a more detailed forecast, please refer
to the latest Surf Zone Forecast (SRFSJU) and the Coastal Hazard
Message (CFWSJU).

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
500 PM AST Sat Nov 30 2024

.SYNOPSIS...

Stable weather conditions will continue across the region due to
the presence of a building mid-to-upper level ridge in the
Atlantic. An increase in moisture content is expected from Sunday
onwards, enhancing the potential for showers across the region.
A northeasterly swell will continue to spread into the local
waters and increasing the potential for life-threatening
rip currents along the northern exposed beaches of the islands.

&&

.SHORT TERM...Tonight through Monday...

The morning hours featured clear to partly cloudy skies with quiet
weather conditions, though a few showers were observed over the
eastern sectors of Puerto Rico and surrounding islands, no
significant accumulations were recorded. Winds were predominantly
from the east-southeast, with variations due to sea breezes. Surface
observations indicated daytime maximum temperatures mostly in the
mid/upper 80s to low 90s across coastal and urban areas, slightly
above normal for this time of year. These areas also experienced
limited heat risk. In higher elevations of the islands, temperatures
ranged from the mid 70s to low 80s. Notably, the climate site at
Luis Munoz Marin Airport reached 91 degrees today, breaking the
previous record of 88 degrees set in 2021. During the afternoon
hours, patches of moisture embedded in the wind flow with
precipitable water values of around 1.7 to 1.9 inches, combined
with surface heating and marginal instability, promoted shower
activity across the northwestern quadrant of Puerto Rico. Based on
radar estimates approximate between 1-1.5 inches of rain fallen.

Tonight, models suggest a patch of drier air (1.10–1.15 inches of
PWAT) will move over the islands, allowing for quiet weather
conditions. The rest of the short-term period remains on track.
Generally, a mid-to upper-level ridge will dominate, while a surface
high-pressure system will remain in place from the Central to
Northeast Atlantic, promoting an east-to-east-southeasterly wind
flow over the next few days. By tomorrow morning, satellite-derived
precipitable water models suggest increasing values across the area,
with PWAT rising back to normal levels (1.75–1.9 inches). This will
result in conditions similar to today, with intermittent showers
across eastern half of Puerto Rico and the islands during the
morning hours, followed by afternoon convection over northwest
Puerto Rico. As a result, a limited flooding risk is expected in
those areas for the remainder of the short-term forecast.

Overall, expect variable weather conditions throughout the forecast
period, with occasional mixed pulses of dry air and moisture
reaching the area each day. This will promote periods of showery
weather, resulting in moderate to locally heavy rainfall,
particularly across eastern and southeastern Puerto Rico and the
USVI. Additionally, afternoon convection expected across the
northwestern sectors of Puerto Rico and the san Juan streamer cannot
be ruled out. Temperature-wise, above-normal heat indices will
continue across urban and coastal areas resulting in limited heat
risk.

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

/From previous discussion.../

The long-term weather forecast remains unchanged. A high-pressure
system over the Central Atlantic, along with another exiting from
the eastern U.S., will restore typical easterly trade winds
across Puerto Rico and the U.S. Virgin Islands. A weak trade wind
disturbance will move through the region during the first half of
the week, bringing afternoon showers and isolated thunderstorms,
particularly over western Puerto Rico. Light-passing showers will
also affect the windward sections during the night and early
morning as moist air moves in. The latest precipitable water model
indicates that moisture levels will be near normal to slightly
above normal through midweek. However, moisture levels will
gradually decrease by the later part of the work week, reducing
the risk of heavy rainfall by the weekend.

From Thursday onwards, drier air will begin to filter into the region,
improving conditions overall. Expect high temperatures in the
upper 80s to low 90s across urban areas and lower elevations.
While temperatures will be warm, the heat risk remains limited, so
it’s important to stay hydrated, particularly during the
afternoons when the sun is at its strongest.


&&

.AVIATION...
(18Z TAFs)

Mostly VFR conditions expected across local TAF sites over the next
24 hours, but SHRA/TSRA will in the vicinity or at site TJBQ will
continue at least through 30/21Z, brief MVFR possible. During the
overnight period into Sunday morning there is moderate chance for
VCSH across the USVI, mainly in TISX. Light and variable winds from
the SE/ESE below 10 kts will persist with winds increasing 10 to 15
kts aft 01/14z with higher gusts. Maximum winds WNW 35-45 kt btwn
FL415-480.

&&

.MARINE...

A surface high pressure building over the central Atlantic will
promote moderate to locally fresh east southeast trade winds. A long
period northeasterly swell across the local Atlantic waters and
passages will continue to affect marine conditions throughout the
weekend. Therefore, mariners can expect confuse seas due to the
combinations of these features.

&&

.BEACH FORECAST...

A long period northeasterly swell will continue to spread across
the local Atlantic waters during the weekend. A high risk of rip
currents is in effect for the northern coastline of Puerto Rico,
from Aguadilla to Humacao, as well as for Culebra and St. Croix.
For more information, please refer to the latest Coastal Hazard
Message (CFWSJU) and Surf Zone Forecast (SRFSJU).

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
515 AM AST Sun Dec 1 2024

.SYNOPSIS...

Today, the atmospheric conditions should remain stable. However,
the development of showers is expected from time to time
particularly during the afternoon hours. A frontal boundary is
forecast to move closer to the islands by the beginning of the
workweek enhancing moisture pooling over the region and
increasing the chance for more frequent showers. The long term
forecast will be dominated mostly by variable weather conditions.

&&

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

The skies over PR and the USVI ranged from mostly clear, with a few
clouds arriving embedded in the winds. The Doppler Radar and
satellite imagery detected rain activity with isolated thunderstorms
across the local Caribbean and Atlantic Offshore waters. Although
winds were mainly from the east-southeast, the land breeze formed
across the coastal areas. The meteorological network marked the low
temperatures across the coastal areas between the mid-and upper-70s
and the low or mid-60s along the mountains.

The mid-to-upper-level ridge pattern will continue to promote a
somewhat stable atmosphere across the islands, regardless of one or
two thunderstorms that will develop during the afternoon across the
western sections of PR and the local waters during the overnight
hours. Meanwhile, the surface high pressure (extending from the
Central to Northeast Atlantic) and a frontal boundary from Cuba to
the Western/Central Atlantic will result in an east-to-east-
southeasterly wind flow. Under the described weather pattern, we can
expect a mix of sunshine and clouds throughout the forecast period.
The arrival of occasional pockets of moisture, enhanced by local
effects, will lead to occasional showers, resulting in moderate to
locally heavy rainfall. These showers will move quickly across the
areas they impact, particularly affecting the windward sections of
the eastern half of Puerto Rico and the U.S. Virgin Islands. This
pattern will primarily develop during the evening and early morning
hours. Additionally, afternoon convection is expected to occur in
the mountainous regions and western parts of Puerto Rico and
downwind from El Yunque into the San Juan metropolitan area.

The frontal boundary is forecast to move closer to the islands,
enhancing moisture pooling over the region and increasing the chance
to observe more frequent showers from late Monday night into early
Tuesday morning. At the same time, a short wave trough aloft will
weaken the ridge pattern, increasing the instability and thus
increasing the chance of observing better afternoon convection on
Tuesday.

Although temperatures are not as hot as during the summer, above-
normal heat indices will continue, especially across the urban
coastal areas of PR and the USVI.

&&

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

As we look ahead to the coming days, the citizens and visitor of
Puerto Rico and the U.S. Virgin Islands could expect and increase
in shower activity as a pre frontal trough develops in the eastern
side of the Dominican Republic from Wednesday into Thursday.
However, Thursday is expected to be a transition day as a high-
pressure system move in from the eastern coast of the United
States and situate over the western Atlantic. Under the influence
of this high- pressure system, the prevailing wind flow will be
from the east. As a result, expect mostly calm weather conditions
with the intrusion of some passing showers from time to time, as
well as the typical afternoon rainfall and isolated thunderstorm
development across the western sections of Puerto Rico.
Temperatures should remain relatively warm but comfortable due to
the steady air movement.

However, a shift in the weather is expected by late Sunday into
Monday. We are forecasting the development of a multi-level low-
pressure system just north of the islands, which will likely bring
changes to the regional weather. A low-pressure system is
characterized by rising air and a general instability in the
atmosphere, leading to the potential for cloud formation and
increased precipitation, meaning that this could be the case for
Puerto Rico, Vieques, Culebra, Saint Thomas, Saint John, and Saint
Croix. The latest model guidance suggests above-normal
precipitable water values for this time of the year and the 500 mb
temperatures around -7 degrees Celsius, meaning there is a
potential for storms to develop vertically and generate
significant rainfall and thunderstorm activity. Nevertheless,
there is medium confidence in the forecast for the later part of
the long-term period.

Overall, we anticipate variable weather conditions, with a mix of
sun, clouds, localized rainfall, and potential for thunderstorm
development.

&&

.AVIATION...
(06Z TAFs)

Expect VFR conditions; however, occasional quick passing SHRA/-SHRA
will move across the local flying area. These +SHRA/SHRA will result
in brief MVFR conditions, especially at JSJ/ISX/IST. Expect calm to
light and VRB winds through 01/13z when they return from the E/ESE
at 10 to 15 kt with higher gusts and sea breeze variations. Between
01/17-22z, TSRA will develop across the NW-PR, affecting the
vicinity of JBQ, with a moderate chance of impacting the terminal.

&&

.MARINE...

A surface high pressure building over the central Atlantic will
promote moderate to locally fresh east southeast trade winds. A long
period northeasterly swell across the local Atlantic waters and
passages will continue to affect marine conditions through at least
today. Therefore, mariners can expect confuse seas due to the
combinations of these features.

&&

.BEACH FORECAST...

A long period northeasterly swell will continue to spread across
the local Atlantic waters through this afternoon. A high risk of
rip currents is in effect for the northern coastline of Puerto
Rico, from Aguadilla to Humacao, as well as for Culebra and St.
Croix. For more information, please refer to the latest Coastal
Hazard Message (CFWSJU) and Surf Zone Forecast (SRFSJU).