Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
226 AM AST Mon Dec 15 2025

...New SHORT TERM, LONG TERM, AVIATION...

.KEY MESSAGES...
Issued at 214 AM AST Mon Dec 15 2025

* A surge in moisture associated with a pre-frontal trough moving
to the north of the area will promote more unstable and wet
conditions during the first half of the workweek across the U.S.
Virgin Islands and Puerto Rico.

* Choppy to rough seas are expected to continue across the
offshore Atlantic waters through at least today.

* A northwesterly swell is forecast to arrive by midweek,
deteriorating marine and coastal conditions through the upcoming
weekend.

&&

.Short Term(Today through Wednesday)...
Issued at 214 AM AST Mon Dec 15 2025

A surge in moisture associated with a pre-frontal trough moving to
the north is expected in the short-term period. The precipitable
water content (PWAT) is expected to increase to near 1.75 inches
late today, with no significant change in moisture levels through
the rest of the short-term period. Latest satellite imagery
indicates an area of cloudiness and showers moving over the Leeward
Islands into the Anegada Passage. This area will then reach the USVI
early this morning and spread across PR throughout the day. As the
local area lies between the front and a distant surface high
pressure, winds will generally persist from the east to southeast at
5 to 15 knots. For Tuesday and Wednesday, no significant variations
in moisture content are expected. However, the 500mb temperatures
are forecast to be the coldest on Tuesday afternoon, around -6.5C,
which should favor heavier showers and isolated thunderstorm
development. Ponding of water in roads and other poor drainage areas
can be expected each day across the islands, with a higher chance of
urban and small stream flooding on Tuesday in PR.

&&

.Long Term(Thursday through Monday)...
Issued at 214 AM AST Mon Dec 15 2025

The forecast remains on track with previous discussions. A
building surface high-pressure system over the western Atlantic
will continue to push lingering moisture from a frontal boundary
into the local area from Thursday into Friday. This will increase
the frequency of passing showers across Puerto Rico and the U.S.
Virgin Islands, particularly during the morning hours across the
windward portions. As the surface high continues to move over the
Atlantic Ocean, another frontal boundary will move east of the
eastern coast of the CONUS, promoting a northeasterly wind flow
across the area. Under this pattern, cooler temperatures will be
felt across the region during the upcoming weekend. By Sunday,
another surface high pressure behind the front is expected to
strengthen north of the local area, bringing slightly drier
conditions; nonetheless, patches of moisture will continue to move
into the islands, promoting showers from time to time.

&&

.AVIATION...
(06Z TAFS)
Issued at 214 AM AST Mon Dec 15 2025

Mainly VFR conditions are expected early in the fcst period.
However, SHRA en route from the Leeward Islands will reach the USVI
terminals btw 15/12-16z, this may lead to tempo MVFR conds,
particularly at TIST. Additional SHRA is expected to develop in and
around TJSJ and TJBQ btw 15/16-22z, which could lead to brief MVFR
cigs. Winds will increase 8-12 kt from the ESE, with sea breeze
variations at TJSJ/TJBQ aft 15/14z.

&&

.MARINE...
Issued at 214 AM AST Mon Dec 15 2025

A surface high-pressure system across the eastern into central
Atlantic will continue to promote moderate to locally fresh east to
southeast winds across the local waters today. Wind-driven seas
are promoting hazardous marine conditions for small craft
operators across the offshore Atlantic waters, where a Small Craft
Advisory remain in effect at least through Monday morning. A cold
front and another surface high-pressure system will move from the
western Atlantic into the central Atlantic over the next few
days, weakening the pressure gradient and allowing for gentle to
moderate winds from late today and Tuesday. By midweek,
increasing winds and a northwesterly swell will likely deteriorate
marine conditions once again.

&&

.BEACH FORECAST...
Issued at 214 AM AST Mon Dec 15 2025

A moderate risk of rip currents will continue along most beaches
of the islands through mid-week. This means that life-threatening
rip currents are possible in the surf zone, and beachgoers are
encouraged to exercise caution. The moderate risk of rip currents
is expected to prevail across north-facing beaches of Puerto
Rico, Culebra, and the U.S. Virgin Islands, with a low risk
elsewhere. Remember that even when the risk is low, life-
threatening rip currents can still occur, especially near groins,
jetties, reefs, and piers.

By midweek, beach conditions are anticipated to deteriorate again
due to increasing winds and a northwesterly swell spreading across
the local Atlantic waters.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
524 AM AST Tue Dec 16 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...
Issued at 426 AM AST Tue Dec 16 2025

* Showers will move across the US Virgin Islands at times today,
producing moderate to locally heavy rainfall.

* Showers and isolated thunderstorms this afternoon may lead to a
slight chance of flooding and thunderstorm impacts, extending
from El Yunque into the San Juan metropolitan area and across
the northwest quadrant.

* A long-period northerly swell will arrive late tonight, creating
a high risk of rip currents along the exposed north-facing
beaches in PR, spreading to the rest of the north-facing beaches
from Aguadilla to Fajardo, Culebra, and the northern US Virgin
Islands on Wednesday.

&&

.Short Term(Today through Thursday)...
Issued at 426 AM AST Tue Dec 16 2025

We had calm weather with clear skies, which allowed for nighttime
cooling, resulting in pleasant low temperatures across Puerto
Rico and the US Virgin Islands overnight. Winds were calm to light
and variable, allowing the land breeze to form overnight.

Early this morning, a high likelihood of generally calm
conditions prevailed across the U.S. Virgin Islands; however, a
low-level perturbation embedded in the easterlies is expected to
introduce periods of cloudiness and passing showers,
intermittently affecting the local waters and islands. As this
feature progresses westward, the probability of showers is
expected to increase across the St Croix and the eastern third of
Puerto Rico by mid-morning, with precipitation chances rising
from low (10-20%) to moderate (30-40%) from late morning through
the afternoon across St. Croix and eastern Puerto Rico.

By early to mid-afternoon, model guidance suggests a moderate to
high likelihood (40-70%) of showers developing across the San
Juan metropolitan area and the northwest quadrant of Puerto Rico.
As a perturbation aloft approaches from the west, a slight chance
of isolated thunderstorms is anticipated, particularly during the
afternoon and early evening when instability peaks. Shower
activity is expected to gradually diminish after approximately 8
PM AST, as convection shifts offshore, allowing for a higher
probability of decreasing cloud cover and calmer conditions.
Nonetheless, another surge of moisture embedded in the easterlies
late tonight into early Wednesday morning may increase the
likelihood of showers, with locally moderate to heavy rainfall
possible.

On Wednesday, the weakening of the mid- to upper-level ridge
associated with an approaching upper-level trough, combined with a
jet streak maximum north of the region, will likely enhance
vertical development. At the surface, another low-level
perturbation is expected to increase moisture availability, and
when combined with diurnal sea-breeze convergence, will maintain a
moderate to high probability of showers, particularly across
western Puerto Rico during the afternoon. Consequently, the risk
of flooding rainfall ranges from slight across eastern Puerto Rico
to elevated across the interior and western sections. While a
flooding risk remains unlikely across the U.S. Virgin Islands,
brief periods of moderate to heavy rainfall cannot be ruled out.

By Thursday, model consensus indicates a strengthening ridge over
the Northeast Caribbean, promoting subsidence and drier air aloft.
Despite this, persistent easterly flow will likely sustain a
moderate chance (30–50%) of passing showers, especially across
windward areas of Puerto Rico and the U.S. Virgin Islands during
the afternoon and overnight periods.

&&

.Long Term(Friday through Tuesday)...
Issued at 426 AM AST Tue Dec 16 2025

Mid- to upper-level ridging will dominate the pattern at the
beginning of the long-term period, maintaining generally stable
conditions across the northeastern Caribbean. Subsidence associated
with the ridge will limit vertical development for the most part,
while mid-level relative humidity remains near climatological
values, occasionally dropping to very dry levels near or below 10
percent. This will tend to cap convection and keep shower activity
limited early on.

At the lower levels, precipitable water values will remain somewhat
near normal for most of the period. Patches of moisture will
continue to stream across the area from time to time, resulting in
passing showers, mainly across windward sections and during the
overnight and early morning hours. Rainfall amounts should remain
light and localized with minimal impacts.

Toward the latter portion of the long-term forecast, the mid-level
ridge begins to erode as a polar trough exiting the eastern U.S.
seaboard approaches from the northwest. This will introduce cooler
air aloft, with 500 mb temperatures falling into the -7 to -8 C
range. As a result, lapse rates will steepen, and the environment
will become increasingly unstable. At the surface, an associated
frontal boundary is expected to approach from the northwest late in
the forecast window. Columnar moisture will begin to increase, with
PWAT values trending upward with this setup. The combination of
cooling aloft, increasing moisture, and improved forcing suggests a
more unsettled pattern developing heading into the Christmas period.

This evolving setup could support a higher potential for
thunderstorms and periods of locally heavy rainfall, increasing
the risk for flooding in prone areas. Confidence remains lower at
this time, given that these features occur late in the forecast
window, where uncertainty in timing and strength remains higher.
Subsequent forecasts will continue to refine the potential
impacts, if any.

&&

.AVIATION...
(06Z TAFS)
Issued at 426 AM AST Tue Dec 16 2025

Mainly VFR conditions across all TAF sites. Winds will continue
calm to light and VRB, becoming E-SE winds at 10 to 15 kts, with
higher gust and sea breeze variations aft 16/13Z. -SHRA/SHRA will
approach from the east, first near IST/ISX this morning, spreading
to PR (JSJ) by mid-morning and near JBQ around noon into the
evening. There is a slight risk of TSRA near JBQ/JSJ this
afternoon and evening.

&&

.MARINE...
Issued at 426 AM AST Tue Dec 16 2025

A cold front moving eastward across the Western Atlantic with a
prefrontal trough interacting with an Azores surface high will
promote a moderate to locally fresh easterly wind flow across the
islands today. The cold front will approach the northeast Caribbean
on Wednesday and Thursday and remain off to the northwest of the
islands, bringing trade wind perturbations across the islands,
resulting in showers and afternoon or early evening thunderstorms. A
long period northerly swell will arrive across the local waters late
tonight into Wednesday, deteriorating marine and coastal conditions.
Thus, Small Craft Advisories will be in effect for the middle of the
week.

&&

.BEACH FORECAST...
Issued at 426 AM AST Tue Dec 16 2025

The north and east-facing beaches of PR and the US Virgin Islands
can expect a moderate risk of rip currents through this evening.
The risk of rip currents is low along the west and south-facing
beaches. Then, the arrival of a long-period northerly swell will
increase the risk to high levels for the PR Atlantic Coastline. By
Wednesday, the risk will spread to high from Rincon to Fajardo,
Culebra, St Thomas, and St John. We encourage beachgoers to
monitor the beach forecast, as there is a moderate chance of High
Surf Conditions due to dangerous breaking waves, which could
promote life-threatening coastal conditions along these beaches,
especially on Wednesday.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
532 AM AST Wed Dec 17 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...
Issued at 429 AM AST Wed Dec 17 2025

* Life-threatening breaking waves and rip currents will impact the
north-facing beaches of PR from Rincon to Fajardo and Culebra.

* Life-threatening rip currents will form along the exposed north-
facing beaches in St Thomas and St John.

* Showers and isolated thunderstorms this afternoon may lead to a
slight chance of flooding and thunderstorm impacts, extending
from El Yunque into the San Juan metropolitan area and into the
interior, north- central, and northwest PR.

* Dangerous marine conditions for small craft operators will
prevail today across the local Atlantic Waters, and Caribbean
Passages.

&&

.Short Term(Today through Friday)...
Issued at 429 AM AST Wed Dec 17 2025

Although we observed calm weather with pleasant overnight low
temperatures, a pre- frontal trough brought passing showers across
the windward locations in PR and the US Virgin Islands overnight.
Additionally, a long- period north- northwesterly swell promoted
the formation of life- threatening rip currents along the north-
facing beaches in PR and the US Virgin Islands early this morning.
Winds were calm to light and variable, allowing the land breeze
to form overnight. However, the passing showers lead to occasional
gusty winds.

We have moderate/high confidence that a long-period northwesterly
swell will create life-threatening breaking waves and rip
currents, and minor coastal flooding at the most vulnerable
coastal locations from Rincon to Fajardo, especially this morning
around high tide. Also, life-threatening rip currents will form on
the north-facing beaches in Culebra, St. John, and St. Thomas.

There is a high confidence (60-80%) of mostly calm and stable
conditions across the interior, western, and southern plains of
Puerto Rico during the early morning hours, resulting in limited
weather impacts in those areas. In contrast, a pre-frontal trough
is expected to increase the likelihood of passing showers across
the U.S. Virgin Islands and the windward sections of Puerto Rico
this morning, with a moderate probability (30-50%) of brief
moderate to locally heavy rainfall.

As the day progresses, east to east-southeast winds associated
with the pre-frontal trough will likely favor the development of
El Yunque Streamer, extending into the San Juan Metropolitan
Area, and afternoon convection over portions of the interior,
north-central, and northwest Puerto Rico. In these areas, there
is a moderate to high chance (40–70%) of periods of moderate to
locally heavy rainfall, which could lead to localized ponding of
water in poor drainage areas and brief reductions in visibility,
especially during the afternoon commute, as well as isolated urban
and small stream flooding.

The proximity of an upper-level trough and a jet streak will
introduce marginal instability, resulting in a slight chance of
isolated thunderstorms during the afternoon and evening hours
across parts of Puerto Rico and the surrounding U.S. Virgin
Islands waters. However, most model guidance indicates that the
strongest dynamical support will remain north of the region,
limiting thunderstorm coverage and keeping the overall flooding
risk low, with only a localized and brief flooding threat in areas
experiencing repeated heavy showers.

Looking ahead to Thursday and Friday, confidence is high that a
mid- to upper-level ridge will build over the Northeast Caribbean,
promoting subsidence and drier air aloft. Despite this,
strengthening easterly trade winds will maintain a moderate to
high chance (30–60%) of passing showers across windward locations
of Puerto Rico and the U.S. Virgin Islands. These showers will be
most frequent during the overnight and early morning hours, with
some activity likely spreading into the interior and western
Puerto Rico during the afternoon, resulting in generally minor but
recurrent wet-weather impacts.

&&

.Long Term(Saturday through Wednesday)...
Issued at 429 AM AST Wed Dec 17 2025

Saturday through Wednesday...

A mid-to-upper-level ridge will dominate local weather for the first
half of the period, maintaining stable conditions aloft. During this
time, precipitable water (PWAT) values will remain below the
seasonal climatological values, ranging from 1.2 to 1.5 inches. At
the surface, patches of low-level moisture will continue to drift
into the area, bringing passing showers to windward sections of the
islands. Rainfall accumulations will stay limited, though localized
afternoon showers are possible across western Puerto Rico. Overall
impacts are expected to remain minimal.

Transitioning into the second half of the period and through
Christmas Eve, a wetter pattern will evolve. The mid-level ridge
will erode as a polar trough, exiting the eastern U.S. coast,
approaches from the northwest. This will increase instability, with
500mb temperatures dropping to between -6 and -8°C. At the surface,
an associated frontal boundary is forecast to approach late Tuesday
into Wednesday. During this period moisture will increase, with PWAT
values reaching 1.5 to 1.75 inches. This combination of cooling
aloft and increased moisture suggests an unsettled pattern for the
Christmas holiday, potentially bringing isolated thunderstorms and
locally heavy rainfall that could increase the risk of flooding in
prone areas starting late Tuesday or Wednesday.

&&

.AVIATION...
(06Z TAFS)
Issued at 429 AM AST Wed Dec 17 2025

Passing SHRA/+SHRA will impact JSJ/IST and ISX throughout the day.
Then, between 17/16-23z, we have a moderate confidence that TSRA
will form near JSJ and JBQ, when MVFR conditions could develop.
Winds will prevail calm to light and VRB thru 17/13z, then we
expect E-ESE winds at 10 to 15 kt with higher gusts and sea breeze
variations. Calm to light/VRB winds will return aft 17/23z. There
is a slight chance that TSRA could develop during the evening
along the PR's Atlantic Coastline.

&&

.MARINE...
Issued at 429 AM AST Wed Dec 17 2025

A cold front extending from around Turks and Caicos to the
northeastern Atlantic and a pre-frontal trough will promote moderate
to locally fresh east to east-southeast winds across the islands
today. Meanwhile, a long-period north-northwesterly swell will create
hazardous marine conditions for small craft throughout the day. Thus,
a Small Craft Advisory is in effect for the Atlantic and Caribbean
Passages. The frontal boundary will linger off to the northwest as an
occluded low form over the Central Atlantic, far to the northeast of
the region, Thursday and Friday.

&&

.BEACH FORECAST...
Issued at 429 AM AST Wed Dec 17 2025

A long period north to northwesterly swell will create life-
threatening breaking waves and rip currents along the north-facing
beaches in Puerto Rico from Rincon to Fajardo, and Culebra.
Meanwhile, the north- facing beaches in the US Virgin Islands can
expect life- threatening rip currents throughout the day. By this
evening the risk will spread to the southwest of Puerto Rico and
Vieques. We encourage beachgoers to avoid visiting these beaches.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
506 AM AST Thu Dec 18 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...
Issued at 500 AM AST Thu Dec 18 2025

* A subsiding northerly swell will continue to produce hazardous
marine and beach conditions today. The High Surf Advisory
remains in effect along northern Puerto Rico and Culebra until
this afternoon, while the High Risk of Rip Currents remains in
effect until early Friday.

* Marine and beach conditions are forecast to deteriorate again
from Saturday afternoon into Sunday due to strengthening winds
and another northerly swell.

* Mostly fair weather conditions during the morning across PR and
the USVI, then an approaching perturbation is expected to bring
a moderate chance of showers across the interior and western PR
this afternoon.

* Cooler temperatures and better rain chances are anticipated
around mid-week next week due to an approaching frontal
boundary.

&&

.Short Term(Today through Saturday)...
Issued at 500 AM AST Thu Dec 18 2025

Calm weather conditions prevailed across the islands overnight. The
Doppler Radar detected showers moving across the local waters,
windward areas of PR and the USVI overnight, while the leeward areas
mainly remained clear. Minimum temperatures ranged from the low to
mid-70s along the coast to the low-60s in the mountains and valleys.
Winds were primarily from the east with land breeze variations.

A subsiding northerly swell is likely (60 to 80%) to continue
producing hazardous breaking waves of 9 to 11 feet and a high
likelihood of life- threatening rip currents along exposed north-
facing beaches of Puerto Rico and Culebra through much of the day.
Beaches along the north-facing shores of Rincon, Aguada, St.
John, St. Thomas, and adjacent islands have a high probability
(60 to 80%) of experiencing dangerous rip current conditions.
While the swell is expected to gradually subside, hazardous
coastal and surf conditions may persist into the afternoon,
particularly at the most exposed beaches.

Winds are very likely (>80%) to prevail from the east this morning,
shifting to east-northeast this evening and into the weekend. As
drier air moves into the region and a mid- to upper-level ridge
builds overhead, there is a high probability (70 to 80%) of
little to no rainfall across most areas during the morning and
early afternoon. However, an approaching perturbation is expected
to increase cloudiness later today, leading to a low to moderate
chance of showers (10 to 40%) across windward areas of Puerto
Rico and the U.S. Virgin Islands, and a low to moderate chance (20
to 50%) across interior and western Puerto Rico during the
afternoon and evening hours.

From this evening into early Friday morning, increasing moisture
will result in a moderate chance of rainfall (40 to 60%) across
windward areas. Under these conditions, there is a limited risk of
localized flooding across interior and western Puerto Rico this
afternoon and evening, followed by a limited flooding risk across
north and east windward areas overnight into early Friday.

Looking ahead, model guidance continues to show a high likelihood
(>70%) of a strengthening ridge pattern over the Northeast
Caribbean, promoting subsidence aloft and a persistent trade-wind
inversion. As a result, residents and visitors of PR and the USVI
can expect mostly sunny to partly cloudy conditions most of the
time, with periodic surges of moisture bringing passing showers,
primarily across windward areas and regional waters and, due to
local sea-breeze effects, across western Puerto Rico during the
afternoons. Overall, daily rain chances are expected to range from
low (10 to 20%) to moderate (30 to 50%).

&&

.Long Term(Sunday through Thursday)...
Issued at 500 AM AST Thu Dec 18 2025

Late in the weekend and into early next week, a weak mid- to
upper-level ridge will prevail across the region, supporting
generally stable atmospheric conditions. During this period,
precipitable water (PWAT) values are expected to remain below to
near seasonal climatological levels, ranging from 1.2 to 1.6
inches. At the surface, patches of low-level moisture will
continue to move through the area, producing brief passing showers
over windward sections of the islands. Rainfall accumulations
should remain limited, although isolated afternoon showers may
develop across western Puerto Rico. From midweek onward, the mid-
level ridge will gradually weaken as a polar trough departing the
eastern United States advances from the northwest. This pattern
change will increase atmospheric instability, with 500 mb
temperatures cooling to below-normal values between -7 and -10
degrees Celsius. A transition toward higher rain chances is
anticipated, with moderate probabilities (50 to 60%) for scattered
to numerous showers. At the surface, an associated frontal
boundary is forecast to approach the region around Wednesday into
Thursday (Christmas Eve and Christmas Day) and potentially move
across the area. As the front nears, moisture will increase, with
PWAT values rising to between 1.5 and 1.8 inches, within the
seasonal to above-normal range. The combination of cooler
temperatures aloft and increased moisture supports a more
unsettled pattern during the holiday period, including scattered
showers and isolated thunderstorms. Guidance, including the
Galvez-Davison Index, suggests the potential for shallow
convection with isolated thunderstorm development. Periods of
locally heavy rainfall may occur, which could elevate the risk of
localized flooding in flood-prone and poorly drained areas,
including ponding on roadways. At this time, the extended forecast
indicates a limited flood risk. Also, cooler temperatures are
expected in the wake of the possible frontal passage.

&&

.AVIATION...
(06Z TAFS)
Issued at 500 AM AST Thu Dec 18 2025

VFR conditions will prevail through much of the forecast period.
SHRA/-SHRA will then form over the interior and western PR (near
JBQ) btwn 18/17-23z. Then, a surge of moisture will increase the
chance of rain from 18/18z onward over JSJ/IST/ISX. Winds will be
calm-light/var thru this morning, then return from the E after
18/13z at 10-15kt with higher gusts and sea breeze variations. Winds
will turn more from the ENE from 18/18z onward.

&&

.MARINE...
Issued at 500 AM AST Thu Dec 18 2025

Moderate to locally fresh east-northeast winds will continue across
the local waters today. These winds, combined with additional pulses
of a fading northerly swell, will maintain hazardous marine conditions
for small craft, particularly across the Atlantic waters and Mona
Passage. As a result, Small Craft Advisories remain in effect through
at least late tonight and into midday Friday. Another long-period
northerly swell is anticipated to arrive and spread across the local
Atlantic waters and passages during the weekend, keeping hazardous
marine conditions into early next week.

&&

.BEACH FORECAST...
Issued at 500 AM AST Thu Dec 18 2025

A High Risk of rip currents continues today along the western,
northern, and eastern beaches of Puerto Rico, as well as Culebra,
St. Thomas, and St. John. This means life-threatening rip currents
are likely within the surf zone, and beachgoers should strictly
follow the guidance of lifeguards, beach patrol flags, and signs.

Tonight, the risk will decrease to moderate along western Puerto
Rico and St. Thomas, while remaining high along northern Puerto
Rico and Culebra through early Friday. Moderate conditions are
expected Friday into early Saturday; however, beach conditions are
forecast to deteriorate again from Saturday afternoon into Sunday
due to strengthening winds and another northerly swell spreading
across the local Atlantic waters.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
505 AM AST Fri Dec 19 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...
Issued at 500 AM AST Fri Dec 19 2025

* Life-threatening rip currents will prevail across the northern
exposed beaches of Puerto Rico and Culebra through this
afternoon. Moderate risk across the U.S. Virgin Islands.

* Another northerly swell and increasing trade winds will cause
hazardous seas and life-threatening rip currents to redevelop
from Saturday afternoon through Sunday.

* Isolated showers this morning across windward portion of Puerto
Rico and the U.S. Virgin Islands, then drier air will limit
rainfall and promote stable conditions most of the day, with
localized afternoon showers developing across western Puerto
Rico.

* Cooler temperatures and better rain chances are anticipated
around mid-week next week due to an approaching frontal boundary
and better dynamics aloft.

&&

.Short Term(Today through Sunday)...
Issued at 500 AM AST Fri Dec 19 2025

A surge of moisture brought scattered to widespread passing showers
across the local waters, the US Virgin Islands, and the windward
locations in Puerto Rico. This activity results in periods of
moderate to locally heavy rain. Meanwhile, the leeward portions of
PR had calm weather conditions, with mostly clear to partly cloudy
skies overnight. Most of the activity moved out of the USVI region
around 2 AM AST, leaving mostly clear skies early this morning. The
winds were mainly from the northeast, influenced by land breeze
variations. Minimum temperatures ranged from the low to mid-70s
along the coast to the low-60s in the mountains and valleys.

As the overnight surge of moisture exits the region, there is a high
likelihood (70-80%) that a drier air mass will advect into the
islands from the east. This drier air, interacting with a mid- to
upper-level ridge aloft, will very likely (>70%) suppress deep
convection and limit rainfall coverage across Puerto Rico and the
U.S. Virgin Islands through at least Saturday. Overall, a stable
weather pattern is likely to persist (60-80%) through Saturday.

By Sunday, model guidance indicates a moderate to slightly high
confidence (50-60%) that the mid-level ridge will weaken, allowing
moisture to increase into the mid-levels and marginally enhance
atmospheric instability across the region.

Under this pattern, the probability of rainfall today and Saturday
will generally range from low (0-20%) to moderate (30-50%). With
east-northeasterly winds persisting, the highest likelihood of
passing showers will remain over windward areas of Puerto Rico and
the U.S. Virgin Islands during the early morning and evening hours,
while interior and western Puerto Rico will have a low to moderate
chance (20-40%) of afternoon showers driven by local and sea-breeze
effects.

From late Saturday night into early Sunday morning, the probability
of rainfall is expected to increase from moderate (30-50%) to high
(60-70%), as weakening ridging aloft and a surface-level perturbation
enhance low- to mid-level moisture availability. As a result, the
flooding risk is likely to increase from none to limited during
this period. Under a limited risk scenario, frequent periods of
moderate to locally heavy rainfall could lead to ponding of water
on roads and in poorly drained areas, with a low probability of
isolated urban and small-stream flooding.

&&

.Long Term(Monday through Friday)...
Issued at 500 AM AST Fri Dec 19 2025

Early next week, mid level ridging will gradually weaken as a
polar trough exiting the eastern United States advances from the
northwest. Surface high pressure building across the western
Atlantic will promote persistent northeast flow across the region
while a frontal boundary is pushed into the central Atlantic.
Patches of low level moisture will continue to move across the
area, resulting in isolated to scattered showers over windward
sections of Puerto Rico and the U.S. Virgin Islands, mainly during
the night and morning hours. By late morning into the afternoon,
a moderate chance of scattered showers, around 50 percent, is
expected across interior and western Puerto Rico, posing a limited
flood risk on Monday and Tuesday.

From Tuesday onward, atmospheric instability will increase as 500
mb temperatures cool to below normal values between -7 and -10
degrees Celsius. Rain chances will increase, with probabilities
rising to 50 to 60 percent for scattered to numerous showers.A
polar trough will extend southward into the Caribbean, while an
additional upper-level trough will interact with a surface frontal
boundary across the region. The frontal boundary will linger
close to the area, allowing moisture to pool across the region,
while enhanced upper-level divergence and atmospheric instability
will support rising motion. As a result, unsettled weather
conditions will develop,, particularly from Wednesday through
Friday, with increasing cloudiness, showers, and isolated
thunderstorms expected across parts of the Caribbean.

As the frontal boundary approaches and lingers to the north of the
region, precipitable water values will increase to between 1.5 and
1.8 inches, within the seasonal to above normal range. Model
guidance, including the Galvez Davison Index, supports the
potential for shallow convection with isolated thunderstorm
development. Periods of locally heavy rainfall may lead to
localized flooding in flood prone and poorly drained areas,
including roadway ponding. At this time, flood risk ranges from
limited to elevated for portions of Puerto Rico, particularly
across the northeastern sectors. Cooler temperatures are expected
during the holiday period, as indicated by a trend toward below
normal 925 mb temperatures.

&&

.AVIATION...
(06Z TAFS)
Issued at 500 AM AST Fri Dec 19 2025

VFR conditions will prevail through much of the forecast period,
without ruling out a few passing showers near or across JSJ/IST/ISX.
SHRA/-SHRA will then form over the interior and western PR (near
JBQ) between 19/17-23z. Winds will be calm to light and variable
through this morning, then return from the ENE after 19/13z at 10-
15kt with higher gusts and sea breeze variations.

&&

.MARINE...
Issued at 500 AM AST Fri Dec 19 2025

Moderate to locally fresh east to northeast winds will continue
across the local waters today. A Small Craft Advisory (SCA) remains
in effect through midday today for the offshore Atlantic waters, due
to hazardous marine conditions for small craft operators. Seas are
expected to briefly subside this afternoon through early Saturday.
However, another long-period northerly swell, generated by a surface
low over the central Atlantic, will spread across the local Atlantic
waters and Caribbean passages, causing hazardous marine conditions to
redevelop and SCA conditions to return Saturday afternoon into Sunday.

&&

.BEACH FORECAST...
Issued at 500 AM AST Fri Dec 19 2025

A High Risk of rip currents continues through this afternoon along
the north-facing beaches of Puerto Rico and Culebra. Dangerous rip
currents are likely within the surf zone, and beachgoers are urged
to strictly follow guidance from lifeguards, beach patrol flags,
and posted signs. Tonight, the risk is expected to decrease to
moderate for most beaches through Saturday night, while low risk
conditions will prevail along the southern beaches of the islands.
Remember, a moderate risk means that life-threatening rip currents
are possible, and even during low risk conditions, dangerous rip
currents can still occur, especially near groins, jetties, reefs,
and piers.

By late Saturday into Sunday, beach conditions are forecast to
deteriorate again as strengthening winds and another northerly
swell spread across the local Atlantic waters, leading to large
breaking waves. Stay tuned to the forecast and exercise caution at
the beaches.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
531 AM AST Sat Dec 20 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...
Issued at 531 AM AST Sat Dec 20 2025

* A northeasterly long period swell and increasing northeasterly
winds will deteriorate marine and coastal conditions during the
weekend.

* A High Risk of Rip Currents will return this afternoon across the
northern exposed beaches of Puerto Rico and Culebra, as well as
eastern St. Croix throughout the weekend.

* A Small Craft Advisory will be in effect this afternoon for the
offshore Atlantic waters, and then tonight for the Anegada
Passage, and throughout the weekend.

* Mainly fair weather will persist this weekend with passing showers
over windward sectors of PR and the USVI, with afternoon showers
possible mainly over interior to WSW PR.

* Moderate to high rain chances are forecast by mid week next
week. Residents and visitors are encouraged to stay tuned to the
forecast updated as there is still uncertainty.

&&

.Short Term(Today through Monday)...
Issued at 531 AM AST Sat Dec 20 2025

Current satellite derived Precipitable Water (PWAT) imagery indicate
patches of moisture with up to 1.45 in, steered by northeasterly
flow, moving in to the region. This has resulted in light to
moderate passing showers over the local waters and moving into the
eastern region. Since midnight, radar accumulations over eastern
Puerto Rico has resulted in up to isolated amounts of around a
quarter on an inch. On the other hand, minimal accumulations were
detected by radar over the USVI. Patchy fog was observed over areas
of the interior. Lows were in the upper 50s and low 60s across
higher elevations of PR, to the upper 60s and mid 70s across lower
elevations of the PR, to the low to mid 70s across lower elevations
of the USVI.

With moderate to fresh northeasterly flow continuing throughout the
period, patches of moisture and drier air will filter into the
region leaving PWAT values at generally normal values for this time
of the year. This available moisture will mostly be confined to the
lower levels, as a mid to upper level ridge continues over the
region to start the short term period. This ridge will continue to
provide stability and limit shower development. The ridge will
gradually weaken to end the short term period and into the long term
period as a polar trough starts to exit from eastern CONUS.
Nevertheless, the above mentioned patches of moisture will continue
to bring passing showers with generally minor accumulations over
windward areas of the islands during the morning and overnight
hours. Limited afternoon convection also continues to be possible
each day for mainly west/southwest PR due to local and diurnal
effects. Flooding risks will be limited, with mainly ponding of
water over roadways and poorly drained areas. 925 mb temperatures
will be at seasonal values, highs will be in the mid to upper 80s
across lower elevations of the islands, with isolated/urban areas a
bit higher. Lows will remain similar to tonight, with patchy fog
developing over areas of the interior.

&&

.Long Term(Tuesday through Saturday)...
Issued at 531 AM AST Sat Dec 20 2025

By the beginning of the long term, an upper-level trough tied to
the subtropical jet stream will bring cooler mid-level
temperatures as the mid-level ridge weakens and moves westward.
Patches of low level moisture will continue to move across the
area, resulting in isolated to scattered showers over windward
sections of Puerto Rico and the U.S. Virgin Islands, mainly during
the night and morning hours. By late morning into the afternoon,
a moderate chance of scattered showers, around 50 percent, is
expected across interior and western Puerto Rico with low chances
of flooding concerns.

For Wednesday and Thursday, Christmas Eve and Christmas Day,
atmospheric instability will increase somewhat as 500 mb
temperatures continue to cool further to below normal values
between -8 and -10 degrees Celsius. A polar trough will extend
southward into the Caribbean, while an additional upper-level
trough will interact with a surface frontal boundary north of the
region. The frontal boundary will move close to the area or cross
the region, allowing a slight increase in moisture, while enhanced
upper-level divergence. However, the global models have been
somewhat unstable from run to run, but the latest guidance is now
indicating less available moisture compared to yesterday.
Precipitable water (PWAT) values are trending closer to seasonal
levels, generally around 1.5 to 1.6 inches. Although some
uncertainty remains, the reduction in moisture has led to a slight
downward adjustment in rain chances. A moderate chance (around
50%) is expected for scattered showers with isolated thunderstorms.
Galvez-Davison Index values have also lowered, suggesting reduced
instability and supporting only a few isolated thunderstorms,
with convection remaining mostly shallow.

Friday and Saturday, models are suggesting drier-than-normal air,
leading to stable weather. Cooler temperatures are expected during
the holiday period, as indicated by a trend toward below normal
925 mb temperatures.

&&

.AVIATION...
(06Z TAFS)
Issued at 531 AM AST Sat Dec 20 2025

VFR conditions prevailing during the period. Passing -SHRA at or in
the VCTY of TJBQ/TJSJ/TIST/TISX to start the period. -SHRA/SHRA then
forming over interior to WSW PR, near TJPS/TJBQ, by 20/17 - 23Z.
Winds picking up again from the ENE after 10/13Z will be calm to
light and variable through this morning, then will return from the
ENE after 19/13z at 15 - 20 kts, with higher gusts and sea breeze
variations.

&&

.MARINE...
Issued at 531 AM AST Sat Dec 20 2025

Moderate to locally fresh east to northeast winds will continue
for the next few days. A long-period northerly to northeasterly
swell, generated by a surface low over the central Atlantic, will
promote hazardous seas for small craft from this afternoon through
at least late Sunday, particularly across the Atlantic waters and
Anegada passage. Small Craft Advisories are in effect from noon
today due to seas gradually building up to 7 feet.

&&

.BEACH FORECAST...
Issued at 531 AM AST Sat Dec 20 2025

Today, there is a moderate risk of rip currents along the north-
facing beaches of Puerto Rico and the U.S. Virgin Islands. A
moderate risk means that life-threatening rip currents are
possible within the surf zone. This afternoon, the risk is
expected to increase to high as beach conditions deteriorate due
to strengthening winds and another northerly swell spreading
across the local Atlantic waters, leading to large breaking waves.
The high risk will likely extend throughout the entire weekend.
Beachgoers are urged to strictly follow guidance from lifeguards,
beach patrol flags, and posted signs. Stay tuned to the forecast
and exercise caution at the beaches.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
504 AM AST Sun Dec 21 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...
Issued at 411 AM AST Sun Dec 21 2025

* A fading northeasterly long period swell will continue to result
in deteriorated marine and coastal conditions today and tonight.
Another stronger northerly swell will again deteriorate marine and
coastal conditions Tuesday through at least the rest of the
workweek.

* A High Risk of Rip Currents continues for the northern exposed
beaches of Puerto Rico and Culebra, as well as eastern St. Croix,
through 6 AM AST Monday. These conditions then return by around
late Tuesday.

* A Small Craft Advisory continues for the Atlantic waters and the
Anegada Passage until at least midnight tonight. These conditions
then return by around Tuesday.

* Light to moderate passing showers under northeasterly winds will
continue across windward sectors of PR and the USVI today,
afternoon showers then forecast for interior to SW PR.

* For the Christmas Eve into Christmas Day, a wet and unstable
weather pattern is forecast with a moderate to high chance of
widespread showers and thunderstorms. Residents and visitors of
Puerto Rico and the US Virgin Islands are urged to stay tuned
for further updates in the forecast.

&&

.Short Term(Today through Tuesday)...
Issued at 411 AM AST Sun Dec 21 2025

Current satellite derived Precipitable Water (PWAT) imagery indicate
patches of moisture with up to 1.60 in, steered by northeasterly
flow, moving mainly around St. Croix. Other coastal areas currently
have PWAT values of around 1.30 to 1.40 in. Light to moderate
passing showers over the local waters have continued, moving into
coastal windward areas. SInce midnight, radar estimated
accumulations over eastern Puerto Rico have resulted in up to
isolated amounts of around 0.40 in. Radar estimated accumulations
were also detected over Culebra, Vieques, the USVI, north-central PR
and southeastern PR. Patchy fog was also observed over areas of the
interior. Minimum temperatures were in the upper 50s to low 60s
across higher elevations of PR, in the upper 60s and mid 70s across
lower elevations of PR, and in the low to mid 70s across the USVI.

A series of surface highs and frontal lows over the Atlantic will
result in northeasterly steering flow through most of the period.
This will bring in patches of moisture and passing showers embedded
in the trade winds towards windward sectors, resulting in generally
seasonal PWAT values. This available moisture will mostly be
confined to the lower levels, as a mid to upper level ridge
continues over the region to start the week. This ridge will
continue to provide stability and limit vertical shower development.
500 mb temperatures will be warmer than normal, but will gradually
decrease as the period progresses. The ridge will gradually weaken
as the short term period progresses as a polar trough moves over the
western Atlantic late tonight and continues moving east as the
period progresses. 500 mb temperatures will be colder than normal by
Tuesday. Patches of moisture and passing showers with generally
minor accumulations will continue to be steered over windward areas
of the islands during the period, mainly during the morning and
overnight hours. Limited afternoon convection is also forecast each
day for mainly west/southwest PR due to sea breeze convergence and
diurnal hearing. Heavier showers can result in ponding of water over
roadways and poorly drained areas. 925 mb temperatures will be at
seasonal values but with a slight cooling trend as the period
progresses. Maximum temperatures will be in the mid to upper 80s
across lower elevations of the islands, with isolated/urban areas a
bit higher. Minimum temperatures will remain similar to tonight,
with patchy fog also developing over areas of the interior during
the overnight hours.

&&

.Long Term(Wednesday through Sunday)...
Issued at 411 AM AST Sun Dec 21 2025

The previous forecast remains on track, with Christmas Eve into
Christmas Day expected to be the most active and potentially
unstable period of the long-term forecast. Latest model guidance
continues to indicate mid-level temperatures cooling to below-
normal values, particularly around -10 to -11 degrees Celsius,
which would support somewhat higher instability. This pattern will
be associated with a polar trough extending southward into the
Caribbean, while an additional upper-level trough interacts with a
surface frontal boundary north of the region. This boundary is
forecast to move close to the area or possibly cross the region,
promoting an increase in moisture along with enhanced upper-level
divergence.

Even so, precipitable water (PWAT) values remain near typical levels
for late December, generally around 1.5 to 1.6 inches, or near
the 50th percentile/seasonal normal. With moisture trending closer
to seasonal values, rain chances have been adjusted slightly
downward. Expect a moderate chance (around 50 to 60 percent) for
scattered showers with isolated thunderstorms. At this time,
forecast instability appears limited, favoring mainly shallow
convection with only a few thunderstorms. Overall, model solutions
have been fairly consistent from run to run regarding the
approach of these features. However, uncertainty remains regarding
the exact impacts across Puerto Rico and the U.S. Virgin Islands.

A gradual improvement in weather conditions is expected late in
the workweek into the weekend, as drier-than-normal air and a more
stable pattern become established, leading to generally quieter
conditions. Cooler temperatures are expected to persist through
the holiday weekend, supported by a trend toward below-normal 925
mb temperatures. Any rainfall should be limited, with only low-end
shower chances possible if brief patches of moisture move through.

&&

.AVIATION...
(06Z TAFS)
Issued at 411 AM AST Sun Dec 21 2025

Mainly VFR conditions across the terminals. Passing -SHRA at or in
the VCTY of TJBQ/TJSJ/TIST/TISX with, between 21/17 - 23Z, -SHRA
/SHRA developing over interior to WSW PR that can also reach the
VCTY of TJPS/TJBQ. Winds from the NE after 21/13Z up to 15 to 19
kts, with higher gusts and sea breeze variations.

&&

.MARINE...
Issued at 411 AM AST Sun Dec 21 2025

The moderate to locally fresh east to northeast winds will continue
for the next few days. These winds along with pulses of a fading long-
period northerly to northeasterly swell will promote hazardous
seas for small craft, particularly across the Atlantic waters and
Anegada passage. Small Craft Advisories remain in effect due to
seas gradually building up to 8 feet through this evening. Marine
conditions will briefly improve tonight into Monday, before
another stronger northerly swell promotes hazardous marine
conditions for small craft by late Tuesday into midweek.

&&

.BEACH FORECAST...
Issued at 411 AM AST Sun Dec 21 2025

For the rest of the day, a moderate risk of rip currents will
persist as coastal marine conditions deteriorate with the arrival of
the north-northeasterly swell. Therefore, from 6 PM AST onward,
there is a high risk of rip currents across all northern coastal
areas, including Culebra and St. Croix, until Monday evening.
Coastal conditions will improve by Tuesday; however, another
northerly swell will increase the risk up to high again by late
Wednesday into Thursday.

[cycloneye]

The solstice of winter has arrived today and is the shortest day with the sun out in the northern hemisphere.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
537 AM AST Tue Dec 23 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...
Issued at 537 AM AST Tue Dec 23 2025

* The short-term weather pattern remains largely unchanged, with
unstable conditions expected from December 24 through December
25 for the region.

* A limited flooding threat is expected through Thursday, mainly
ponding of water over roadways and poorly drained areas for PR
and the USVI.

* Marine and beach conditions will gradually deteriorate today and
tomorrow; these conditions will continue throughout the week as
pulses of northerly swell arrive. Small Craft Advisories and
High Risk of Rip Currents will soon be in effect.

&&

.Short Term(Today through Thursday)...
Issued at 537 AM AST Tue Dec 23 2025

Overnight conditions were relatively calm, with pockets of passing
showers over the regional waters, some of which reached northern and
eastern sections of eastern Puerto Rico. Temperatures remained cool,
with readings in the 60s across the higher elevations and in the 70s
across urban and coastal areas. The prevailing wind flow was from
the northeast at 5 to 10 mph, with occasional higher gusts near
passing showers.

The overall short-term weather pattern has not changed
significantly, therefore much of the previous discussion remains
valid. From December 24 through December 25, atmospheric conditions
will remain unstable due to the continued influence of a polar
trough at upper levels. Mid-level temperatures between 700 and 500
mb are expected to remain around −10 degrees Celsius, which is at or
below the 10th percentile for this time of the year. This
anomalously cold air aloft will support steep lapse rates and
increased instability. In addition, favorable jet dynamics will
overspread the forecast area, with a 60–90 kt jet at 250 mb
enhancing upper-level ventilation and increasing 0–500 mb bulk
shear, a pattern often associated with more organized convection.
Nevertheless, the primary limiting factor will continue to be
available moisture across the northeastern Caribbean. The associated
frontal boundary remains northwest of the area and is forecast to
gradually sag southward. Precipitable water values are expected to
remain near normal to slightly below normal through Thursday.
Additionally, the persistent northeasterly low-level flow will keep
temperatures below normal, potentially limiting afternoon surface
heating and further restricting deep convective development.

As a result, any convection that develops is expected to be
localized rather than widespread. Relatively fast steering winds
will continue to limit rainfall accumulations, even where heavier
showers occur. Overall, expect periods of showers during the
overnight and morning hours, with isolated thunderstorms developing
mainly over the regional waters. Some thunderstorms may approach
coastal areas, particularly across the Atlantic waters. During the
afternoon hours, showers with isolated thunderstorms may develop
over interior and southwestern Puerto Rico.

At this time, there is a limited flooding threat through Thursday,
December 25, primarily in the form of ponding of water on roads and
in poorly drained areas.

&&

.Long Term(Friday through Tuesday)...
Issued at 537 AM AST Tue Dec 23 2025

Drier air behind the frontal boundary will dominate throughout the
the period. Precipitable Water (PWAT) values are forecast at
around to below an inch with isolated patches of moisture (PWAT up
to around 1.2 in) reaching the area and promote passing showers
from time to time. Although low PWAT values are forecast, upper
troughs will move northeast of the area during the latter part of
this week. building surface high over the western Atlantic and a
frontal low over the north-central Atlantic will promote
northeasterly steering flow to start the period. Model guidance
suggests that winds will gradually veer to start the next week,
promoting southeasterly flow by the end of the period. Under the
northeasterly flow, 925 mb temperatures are forecast to be below
normal. Minimum temperatures are forecast in the 50s to low 60s
across higher elevations of PR, in the upper 60s to mid 70s across
lower elevations of PR, and in the low to mid 70s across the
USVI. Maximum temperatures are forecast around the mid 80s across
lower elevations of the islands, with isolated/urban areas a bit
higher. This will likely enhance patchy fog across sectors of
interior Puerto Rico.

&&

.AVIATION...
(06Z TAFS)
Issued at 537 AM AST Tue Dec 23 2025

All TAF sites should experience VFR conditions across most
terminals through the period. However, SHRA may intermittently
affect TJSJ, TIST, and TISX, especially during the overnight and
early morning hours. TJPS could experience VCSH after 1217Z. Winds
will remain from the NE at 6-10 knots, with occasional higher gusts
near passing showers.
&&

.MARINE...
Issued at 537 AM AST Tue Dec 23 2025

A surface high over the western Atlantic and a frontal low over the
north-central Atlantic will promote moderate east to northeast winds
to start the period. A series of surface highs and frontal lows will
continue moving into the Atlantic during the period, resulting in
moderate to locally fresh northeast winds through at least Wednesday,
becoming moderate by Thursday.

A long-period northerly swell, from the above mentioned frontal
low, will arrive and spread across the offshore Atlantic waters
this afternoon. This will result in choppy to rough seas, becoming
hazardous for small craft. These conditions will continue
throughout the week as seas build to 6 to 9 feet, spreading to the
nearshore Atlantic Waters and local Passages. Another pulse of
swell will arrive later in the workweek and support deteriorated
conditions throughout the end of the week.

&&

.BEACH FORECAST...
Issued at 537 AM AST Tue Dec 23 2025

Although the day will start with a moderate risk of rip currents
for the northern and eastern coastline of Puerto Rico, as well as
for exposed beaches of Culebra and the USVI, conditions will
deteriorate late tonight as a northerly swell arrives. This
northerly long-period swell will increase the risk of rip currents up
to high for exposed northern beaches by late tonight and
throughout the rest of the week. Another pulse of swell will
arrive later in the workweek and support deteriorated conditions
throughout the end of the week.