Caribbean - Central America Weather

[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.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
342 AM AST Wed Dec 24 2025

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

.KEY MESSAGES...
Issued at 317 AM AST Wed Dec 24 2025

* A frontal boundary will be across the area through early
Thursday, increasing the frequency of showers, mainly overnight
and during the morning hours. Rainfall amounts are expected to
remain limited, with minor ponding of water on roads and in
poorly drained areas possible, today.

* Marine and coastal conditions will stay hazardous through the
weekend as increasing northeasterly winds and multiple pulses of
long-period northerly swell create choppy to rough seas and
hazardous conditions for small craft.

* Rip current risk remains high along exposed northern and eastern
beaches of Puerto Rico and Culebra along with a High Surf
Advisory, as a northerly swell builds and persists through the
end of the week.

&&

.Short Term(Today through Friday)...
Issued at 317 AM AST Wed Dec 24 2025

Persistent showers have moved in under a northeasterly wind flow
along Puerto Rico and the Virgin Islands. These showers, although
heavy at times, left just above half an inch of rainfall from
Luquillo to Naguabo, and much less amounts elsewhere.

A frontal boundary is currently approaching the local islands, hence
the showery pattern will persist through much of Christmas Eve. In
fact, the most recent precipitable water products show values just
shy of 1.5 inches, which is what it's expected for this time of
year. Behind the front, high pressure maintains the winds from the
northeast, at speeds of 15 to 20 knots, gusting up to 25 knots. This
breeze will make the showers move faster, reducing the risk of
flooding. Nevertheless, wet roads and ponding of water can be
anticipated today and tonight. Also, late in the afternoon, showers
will fire up along the southwestern quadrant of Puerto Rico. While
thunderstorms were not explicitly added into the forecast, mid
levels temperatures are cool enough to support some isolated
lightning.

On Christmas Day, lingering showers will persist in the early
morning hours, especially for portions of northern Puerto Rico and
also along the Virgin Islands. Later in the day, as the front
crosses the area, a much drier air mass will filter in. This will
cause showers to taper off, with the probability of precipitation
falling from 40-50% today to 10-30% tomorrow afternoon and evening.
Something extra to notice is that temperatures will cool down too,
with values nearly one standard deviation below normal. This will be
more noticeable in the mountains, with lows cooling down to the 50s
and 60s, and in the upper 60s and low 70s in higher elevations. A
similar pattern can be anticipated for Friday, with a low change of
rain, and cooler than normal temperatures.

&&

.Long Term(Saturday through Wednesday)...
Issued at 317 AM AST Wed Dec 24 2025

The inherited forecast remains on track. Drier air behind a frontal
boundary will dominate the region through Monday, with
precipitable water (PWAT) values generally around or below 1.0
inch. However, isolated patches of moisture with PWAT values
reaching around 1.2 inches may occasionally move across the area,
promoting passing showers from time to time. Despite the overall
dry pattern, upper-level troughs will lift northeast of the area
during the latter part of the weekend, while a building surface
high over the western Atlantic and a frontal low over the north-
central Atlantic will promote a northeasterly steering flow at the
start of the period. Model guidance indicates that winds will
gradually veer early next week, promoting a southeasterly flow by
the end of the period. Minimum temperatures are expected to range
from the 50s to low 60s across higher elevations of Puerto Rico,
the upper 60s to mid 70s across lower elevations of Puerto Rico,
and the low to mid 70s across the U.S. Virgin Islands. Maximum
temperatures are forecast to reach the mid 80s across lower
elevations, with isolated urban areas slightly warmer. These
conditions will likely support the development of patchy fog,
particularly across portions of interior Puerto Rico, mainly
during the overnight and early morning hours.

Residents and visitors are encouraged to continue monitoring the
forecast into Tuesday, as model guidance continues to suggest a
gradual increase in moisture content, which could lead to a return
of more active weather conditions.

&&

.AVIATION...
(06Z TAFS)
Issued at 317 AM AST Wed Dec 24 2025

Persistent SHRA will continue to stream along the Atlantic and
Caribbean waters, reaching all the terminals at times, but
particularly, the USVI and TJSJ ones. Brief periods of reduced VIS
and low ceilings could occur near these showers. Winds will be from
the NE at 15 kts, gusting 20-25 kts.

&&

.MARINE...
Issued at 317 AM AST Wed Dec 24 2025

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 continue to spread across the
offshore Atlantic waters today. 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 10 feet,
spreading to the nearshore Atlantic Waters and local Passages.
Another pulse of swell will arrive by the end of the workweek and
support deteriorated conditions throughout the weekend.

&&

.BEACH FORECAST...
Issued at 317 AM AST Wed Dec 24 2025

The northerly long-period swell will continues to filter over the
regional waters maintain the risk of rip currents high for
exposed northern beaches through the rest of the week. A High Surf
Advisory will also be in effect with this swell event, which
could result in localized beach erosion and dangerous swimming
conditions. Another pulse of northerly swell will arrive later in
the workweek, supporting hazardous beach conditions through the
weekend.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
357 AM AST Thu Dec 25 2025

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

.KEY MESSAGES...
Issued at 338 AM AST Thu Dec 25 2025

* Hazardous marine and coastal conditions will persist until the
end of the workweek across all the offshore Atlantic waters
and north- exposed beaches of the islands.

* Frequent passing showers will continue to filter over the
Puerto Rico and the US Virgin Islands through the morning hours
or at least through the first half of the day.

* Weather conditions will begin to improve as the dry air just
behind the frontal boundary moves across the islands.

&&

.Short Term(Today through Saturday)...
Issued at 338 AM AST Thu Dec 25 2025

Moderate to heavy showers, along with isolated thunderstorms were
observed during the night hours across most of the region. The
heaviest activity was observed in San Juan, with radar estimates of
2 to 3 inches of rainfall. Two flood advisories and one Flash Flood
Warning were issued. Most of eastern Puerto Rico collected 1 to 2
inches as well. Rainfall in the Virgin Islands was not as strong,
but passing showers moved inland all night long.

Moisture associated with the frontal boundary is observed in the
satellite derived precipitable water products, with the bulk of the
moisture now between Vieques and Saint Croix. Showers will persist
mostly in the morning hours, impacting portions of Puerto Rico and
the Virgin Islands. Wet roads and ponding of water in low-lying
areas are the main impacts associated with these rains. Water surges
has been observed along the rivers of the northeast, with at least
four streams reacting last night. On the other hand, the drier air
mass is already reaching northwestern Puerto Rico, and moisture will
gradually decrease, so a lot less rain is anticipated later today
and tonight. Showers may persist all day long in the vicinity of St.
Croix, however.

The front is being pushed toward the Caribbean waters by a high
pressure over the western Caribbean. This feature will bring a
breeze from the northeast at 14 to 20 knots, gusting up to 25 knots.
It will also be cooler, with 925 mb temperatures cooling down nearly
one standard deviation for the rest of the short term period. This
will translate in cool nights, with lows in the 50s in the highest
mountains, and in the 60s and low 70s in the lower elevations. It
will warm up during the day, but highs should be mostly in the 70s
in the mountain and the low 80s in coastal areas.

For the rest of the period, mainly fair weather will persist, but it
will not be completely dry. Some showers will continue to stream at
times over portions of northern Puerto Rico and the Virgin Islands,
but no significant impacts are anticipated with these rains. Also, a
long wave trough will weaken the pressure gradient, with speeds
falling below 10 knots on Friday, and 5-8 kts on Saturday.

&&

.Long Term(Sunday through Thursday)...
Issued at 338 AM AST Thu Dec 25 2025

The long-term forecast remains unchanged. Drier air behind a frontal
boundary will dominate the region through Monday, with
precipitable water (PWAT) values falling well below 1.0 inch.
However, isolated patches of moisture may occasionally move across
the area, promoting brief passing showers. Despite the prevailing
dry pattern early in the period, a building surface high over the
western Atlantic and a frontal low over the north-central
Atlantic will promote a northeasterly steering flow through
Monday. 925 mb temperatures are expected to remain below two
standard deviations for this time of year, supporting cooler-than-
usual conditions. Later in the workweek, temperatures are forecast
to moderate back to near-normal values.

Latest model guidance suggests that winds will gradually veer by
Tuesday, becoming southeasterly, allowing Caribbean moisture to
filter across Puerto Rico and the U.S. Virgin Islands. Along with
this wind shift, a trough moving across the area will result in a
wetter pattern, with increasing chances for showers and isolated
thunderstorms by midweek. Confidence regarding the specific timing
and impacts remains medium. Therefore, residents and visitors are
encouraged to continue monitoring the forecast, as more active
weather conditions could develop.

&&

.AVIATION...
(06Z TAFS)
Issued at 338 AM AST Thu Dec 25 2025

SHRA will impact TJSJ and USVI terminals early today, with
intermittent periods of reduced VIS and low ceilings. Conditions
should improve after 15Z. Winds will be from the NNE at 9-13 kts at
FL050, gusting up to 20-25 kts from 14-22Z. Winds will slow down
after 22Z.

&&

.MARINE...
Issued at 338 AM AST Thu Dec 25 2025

A series of surface highs and frontal lows will continue moving
into the Atlantic during the period, resulting in moderate northeast
winds today. A long-period northerly swell, from the above mentioned
frontal low, will continue to spread across the offshore Atlantic
waters. 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 10 feet, spreading to the nearshore Atlantic
Waters and local Passages. Another pulse of long period northerly
swell will arrive by late Friday night into early Saturday morning,
supporting dangerous conditions throughout the weekend.

&&

.BEACH FORECAST...
Issued at 338 AM AST Thu Dec 25 2025

Deteriorating coastal conditions are still expected through at
least the end of the workweek, as a persistent long-period swell
from the north will continue to affect the regional waters. This
swell will continue to result in extremely dangerous conditions
for swimmers, high rip current risk, and localized beach erosion.
Therefore, a high surf advisory is in effect until 6 AM AST on
Thursday, and a high risk of rip current through Friday

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
508 AM AST Fri Dec 26 2025

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

.KEY MESSAGES...
Issued at 500 AM AST Fri Dec 26 2025

* Northerly swell activity today and through the weekend will
maintain hazardous marine conditions and life-threatening rip
current risks, particularly across Atlantic waters and north-
and east-facing beaches. While surf heights may fluctuate, the
potential for high surf conditions cannot be ruled out,
especially with additional swell pulses on Saturday.

* Typical December weather is expected over the next few days,
characterized by cooler temperatures and periods of trade-wind
showers, mainly during the overnight and early morning hours. No
significant weather hazards are anticipated during this period.
However, a gradual increase in moisture and instability from
Wednesday into Thursday (New Year’s period) may result in more
frequent showers and a low potential for isolated lightning
activity.

* U.S. Virgin Islands: The primary threats will be marine and
coastal, driven by ongoing northerly swell activity and life-
threatening rip current conditions. Otherwise, typical seasonal
weather conditions are expected, with brief passing showers and
cooler temperatures.

&&

.Short Term(Today through Sunday)...
Issued at 500 AM AST Fri Dec 26 2025

Northerly swell activity today and through the weekend will
maintain hazardous marine conditions and life-threatening rip
current risks, particularly across Atlantic waters and north- and
east-facing beaches. While surf heights may fluctuate, the
potential for high surf conditions cannot be ruled out, especially
with additional swell pulses on Saturday.

Typical December weather is expected over the next few days,
characterized by cooler temperatures and periods of trade-wind
showers, mainly during the overnight and early morning hours. No
significant weather hazards are anticipated during this period.
However, a gradual increase in moisture and instability from
Wednesday into Thursday (New Year’s period) may result in more
frequent showers and a low potential for isolated lightning
activity.

U.S. Virgin Islands: The primary threats will be marine and
coastal, driven by ongoing northerly swell activity and life-
threatening rip current conditions. Otherwise, typical seasonal
weather conditions are expected, with brief passing showers and
cooler temperatures.

&&

.Long Term(Monday through Friday)...
Issued at 500 AM AST Fri Dec 26 2025

A shift in the weather pattern is expected this week. After a
relatively dry start on Monday and Tuesday, wetter conditions
return Tuesday night and persist through Friday as a weak frontal
boundary dissipates and a short-wave polar trough approaches the
region, with a surface trough reflection increasing moisture and
instability later in the week. Showers will become more frequent,
with periods of moderate to locally heavy rainfall, especially
from Thursday afternoon into Friday. While widespread flooding is
not expected, localized urban and small-stream flooding will be
possible, mainly across windward and interior areas of Puerto Rico
and portions of the U.S. Virgin Islands. Confidence is moderate
that late-week rainfall will be the most impactful part of the
period.

Thunderstorm activity is expected to remain limited overall, which
is typical for this time of year, but there is a low to moderate
chance of thunderstorms Thursday into Friday as the trough
briefly enhances instability and supports isolated thunderstorm
development. Winds will remain a gentle east-southeast to
southeast breeze through Thursday, then veer to the east and
strengthen to a moderate breeze from Thursday night into Friday as
surface high pressure builds and shifts eastward over the North
Atlantic. Temperatures will trend slightly warmer from Wednesday
through New Year’s, with cooler conditions expected to return late
in the week. Confidence is high in the late-week increase in wind
speeds, resulting in breezy conditions at times, especially along
exposed coasts and higher elevations.

&&

.AVIATION...
(06Z TAFS)
Issued at 500 AM AST Fri Dec 26 2025

Mainly VFR conditions expected to prevail. SHRA will move at
times, reaching TJSJ and USVI terminals, but impacts to operations
are expected to be minimal. After 18z, SHRA will develop near
TJPS, with brief periods of reduced VIS and low ceilings possible.
Winds will be from the NE at 7-9 kts.

&&

.MARINE...
Issued at 500 AM AST Fri Dec 26 2025

A surface high pressure centered over the western Atlantic will
promote light to moderate east to northeast winds over the next
few days. Meanwhile, pulses of a long-period northerly swell will
invade the local waters and deteriorate marine conditions,
resulting in hazardous seas for small craft, with Small Craft
Advisories in effect from tonight through Saturday night.
Additional pulses of northerly swell are expected early next week,
which will likely once again bring hazardous conditions for small
craft across the local waters. Typical trade-wind shower activity
will continue to affect the region, especially during the
nighttime hours.

&&

.BEACH FORECAST...
Issued at 500 AM AST Fri Dec 26 2025

A High Rip Current Risk continues today across the Atlantic-facing
beaches of Puerto Rico and Culebra, despite subsiding swell and
gradually improving marine conditions. Hazardous rip current
conditions will remain possible across more protected southern-
facing beaches, as well as Vieques and most U.S. Virgin Islands
beaches, although the risk there is less elevated compared to
Atlantic-facing shores.

Additional pulses of northerly swell arriving tonight are expected
to reinforce life-threatening rip current conditions, with the
high risk expanding to the northern U.S. Virgin Islands on
Saturday. While it is too early to determine exact surf heights,
the potential for high surf conditions exists, and the issuance of
High Surf Advisories cannot be ruled out later today or this
evening.

Beachgoers are strongly urged to remain out of the water,
especially at unguarded beaches, and to heed all local beach
safety statements and advisories.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
444 AM AST Sat Dec 27 2025

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

.KEY MESSAGES...
Issued at 500 AM AST Sat Dec 27 2025

* Pulses of long-period northerly swell will maintain hazardous marine
conditions today, especially across Atlantic waters and local
Caribbean passages. Current and additional swell pulses will
also sustain a life-threatening rip current risk along north-
facing beaches of Puerto Rico, Culebra, and the northern U.S.
Virgin Islands through at least Sunday. High surf risks will
persist through this afternoon at exposed shores. While
conditions may gradually improve thereafter, additional swell
pulses early next week may once again deteriorate marine and
beach conditions.

* Overall weather conditions will remain mostly quiet, with brief passing
showers at times and little to no thunderstorm activity
expected. A slight increase in shower activity and a low chance
of isolated thunderstorms is possible mid- to late week as a
short-wave trough and a weak surface-induced trough approach the
region, though impacts are expected to remain localized.

* U.S. Virgin Islands: Weather conditions will remain generally
stable, with passing showers at times and no thunderstorm
potential, even during the midweek period. No significant inland
weather impacts are anticipated.

* New Year’s Eve: Showers may become more frequent, especially
across western Puerto Rico, with a low chance of isolated
lightning. Forecast confidence is moderate, as model guidance
continues to fluctuate.

&&

.Short Term (Today through Monday)...
Issued at 500 AM AST Sat Dec 27 2025

Clear skies were observed across Puerto Rico and the Virgin Islands
during the night hours. It was very cool too, with some stations
reporting lows in the upper 50s at higher elevations, and the mid
60s to low 70s elsewhere.

Satellite-derived precipitable water imagery show very dry air
across the region, with values of only 0.75 inches, which is well
below the normal value for this time of year. At the surface, high
pressure is centered over the western Caribbean, and a polar trough
is covering most of the Atlantic Ocean. This is causing a weak
steering flow across the local islands, coming out of the northeast
today at 4 to 7 kts, less than 4 knots tomorrow, and from the east
at 5 to 7 kts on Monday. Also, the high will maintain very low
relative humidities at the mid levels, with a trade wind cap
inversion at 850 mb. Under these conditions, heavy showers are not
expected to develop, but local effects may still trigger some
showers along the interior and western Puerto Rico. Impacts are
expected to be very limited, possibly with ponding of water and wet
roads.

Temperatures will remain very comfortable too, with 925 mb values at
one to two standard deviations below normal. For mountains: expect
lows in the 50s and 60s, and highs in the low 70s. For low
elevations and coastal areas: expect lows in the 60s and low 70s,
and highs in the low 80s.


&&

.Long Term (Tuesday through Saturday)...
Issued at 419 AM AST Sat Dec 27 2025

From Tuesday through Thursday, a dry and stable winter pattern
will dominate, supported by post-frontal dry air pushing southward
and weak mid-level ridging. This will favor mostly fair weather,
limited shower activity, and cooler nighttime temperatures typical
for this time of year. During this same period, an eastward-moving
surface high north of the region will mainly influence the wind
pattern, maintaining a gentle to moderate east-southeast breeze
through Thursday.

A slight transition is expected later in the period as a short-
wave trough approaches from the west. Although the latest guidance
indicates its axis will remain west of the islands, it will still
influence the region by weakening the mid-level ridge and
supporting the development of a weak surface trough late Friday
into Saturday. This setup may allow moisture to shift back toward
the area, with the highest sensitivity across western Puerto Rico
and the Mona Passage, while other areas experience more limited
effects.

From Wednesday night into Saturday, showers may become more
frequent in favored areas, especially across western and interior
Puerto Rico and exposed coastal locations, with a few periods of
locally heavy rainfall possible. A low chance of isolated
thunderstorms exists late Friday into early Saturday, mainly over
western Puerto Rico and nearby waters, producing brief heavy rain,
gusty winds, and lightning. Winds are expected to weaken and
become more variable late Friday into Saturday due to the surface
trough, which may support a warmer-than-normal feel on Friday,
particularly during the afternoon. Forecast confidence is
moderate, as moisture fields continue to shift and guidance
oscillates between wetter and drier solutions. This variability is
not necessarily negative, as New Year’s Eve currently trends
drier with generally favorable conditions, though marine and beach
hazards may continue.


&&

.AVIATION...
(06Z TAFS)
Issued at 500 AM AST Sat Dec 27 2025

VFR conditions expected to prevail through the forecast period. SHRA
is expected after 17Z for TJPS, with brief periods of reduced VIS
and low ceilings. After 22Z, VCSH are expected for TJSJ and USVI
terminals, but impacts are expected to be limited. Winds will be
from the ENE from 5-9 kts, becoming light and variable after 22Z.


&&

.MARINE...
Issued at 500 AM AST Sat Dec 27 2025

A surface high pressure system over the western Atlantic will
maintain light to moderate east to northeast winds across the
local waters over the next few days. Meanwhile, pulses of long-
period northerly swell will continue to spread into the region,
maintaining hazardous marine conditions. Small Craft Advisories
remain in effect through this afternoon, with rough seas
persisting afterward as the swell gradually diminishes. Looking
ahead, additional pulses of northerly swell are expected early
next week, which may bring another round of hazardous conditions
for small craft across the local waters.


&&

.BEACH FORECAST...
Issued at 500 AM AST Sat Dec 27 2025

A High Rip Current Risk remains in effect through tonight along
north-facing beaches of Puerto Rico, Culebra, St. Thomas, and St.
John, while a High Surf Advisory remains in effect through 6 PM
this evening for the north coast of Puerto Rico. Recent buoy
observations (NE Puerto Rico buoy 41043) confirm additional pulses
of long-period northerly swell, bringing seas of 7–8 feet with
periods of 12–13 seconds across the local Atlantic waters and
Caribbean passages. These conditions support the potential for
breaking waves exceeding 10 feet at exposed beaches, reinforcing
dangerous and life-threatening swimming conditions today.

Beachgoers are strongly urged to stay out of the water at north-
facing beaches, especially at unguarded locations, and to follow
all beach flag warnings and coastal advisories. For additional
details and the latest updates, refer to the Coastal Hazard
Message (CFWSJU).


&&

.FIRE WEATHER...
Issued at 500 AM AST Sat Dec 27 2025

Drying conditions continue to develop, especially across southern
Puerto Rico, where localized abnormally dry conditions persist. Monthly
rainfall has been minimal, and 30- to 60-day rainfall deficits
continue, supporting the ongoing drying of fine fuels.

There is no elevated fire danger today. While there is some
uncertainty in drought and soil moisture indices, KBDI values have
increased to around 540 at Cabo Rojo and 503 at Camp Santiago,
indicating increasing fuel dryness, though still below thresholds
for Fire Weather Statement or Red Flag Warning. Low relative
humidity at times, combined with occasional wind gusts of 20–25
mph typical of winter trade-wind patterns, has briefly enhanced
fire spread potential, with a few small wildfires observed.
Overall, fire danger remains low at present, but continued drying
over the next several days to weeks could elevate fire risk,
warranting close monitoring, particularly across southern Puerto
Rico.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
420 AM AST Sun Dec 28 2025

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

.KEY MESSAGES...
Issued at 420 AM AST Sun Dec 28 2025

* Smaller pulses of long-period northerly swell will continue to
spread across the region through midweek, maintaining a high
potential for life-threatening rip currents along Atlantic- and
north-facing beaches of Puerto Rico, including Culebra, and
across the northern U.S. Virgin Islands. This risk remains
likely through at least Monday and may extend into midweek.

* Conditions will remain mostly quiet through midweek, with brief
passing showers at times and little to no thunderstorm activity
expected. A wetter transition is likely late in the week as an
upper-level disturbance and a weak surface trough approach,
though impacts are expected to be localized.

* Weather conditions will remain generally stable with passing
showers at times. Shower and thunderstorm activity may increase
toward the end of the week.

* New Year’s Eve: Unsettled but manageable conditions with breezy
trade winds, occasional passing showers, cooler temperatures
early, and a continued high risk of life- threatening rip
currents along north- and Atlantic-facing beaches.

&&

.Short Term(Today through Tuesday)...
Issued at 420 AM AST Sun Dec 28 2025

Skies were clear during the night hours, allowing for temperatures
to cool down once again to the 50s in the mountains, and the 60s in
lower elevations. A few showers managed to develop over the local
waters, but none reached land areas.

A polar trough maintains the pressure gradient weak, with a steering
flow of only 3-7 kts. At the mid and upper levels, relative
humidities are very low, and a trade wind cap will stay in place
around 800 mb. At the low levels, moisture will remain near two
standard deviations below normal, with values of 0.6 to 0.8 inches.
Some small patches of moisture may filter in at times, but still,
the probability of rain for the period is not greater than 30%, and
focused in portions of eastern Puerto Rico and the Virgin Islands.
Temperatures will remain cooler than normal, especially today and
tomorrow. Lows will be in the 50s and low 60s for the mountains.
Highs will be in the low 70s for the higher mountains and in the low
and mid 80s for coastal areas.


&&

.Long Term(Wednesday through Sunday)...
Issued at 420 AM AST Sun Dec 28 2025

Expect periods of unsettled weather with brief periods of heavy
rain and occasional lightning. Breezy trade winds will bring
frequent passing showers, especially from Wednesday into early
Thursday, with cooler-than- normal temperatures at the start of
the period. Weather conditions become more active Friday into
Saturday as a short-wave trough and surface-induced trough moves
through the region, then gradually improve late in the weekend.
Temperatures are expected to slowly warm, with warmer-than-normal
conditions possible by the weekend.

The main weather concerns will be rainfall, lightning, and gusty
winds. The highest risk period is expected from Friday morning into
Friday night, when scattered to locally numerous showers and
isolated thunderstorms are likely. Lightning and brief strong
wind gusts hazard risks will be more likely during this time, and
trade winds will be strongest around Friday evening. From
Saturday into Sunday, showers will still occur, but thunderstorm
activity should gradually decrease. A lower confidence increase
in thunderstorm potential may return late Sunday night, depending
on how conditions evolve with the proximity of the next short-
wave trough.

&&

.AVIATION...
(06Z TAFS)
Issued at 420 AM AST Sun Dec 28 2025

VFR conditions expected for today. Winds will be mostly light. From
14-22Z, winds will be from the NNE at 7-10 kts, and after 22Z, winds
will be at 3-5 kts. There is a low chance of SHRA in the vicinity of
TJPS, but impacts to operations are expected to be minimal to
none.

&&

.MARINE...
Issued at 420 AM AST Sun Dec 28 2025

A surface high over the western Atlantic will maintain light to
moderate east to northeast winds across the Caribbean waters,
while winds across the Atlantic waters remain light and variable
through midweek, becoming more uniform across the region toward
the end of the workweek. Smaller pulses of northerly swell will
continue through midweek; while hazardous seas are not expected,
small craft are advised to exercise caution, especially across the
Atlantic waters and passages. Shower and thunderstorm activity
increases mid to late week, with locally hazardous marine
conditions possible.

&&

.BEACH FORECAST...
Issued at 420 AM AST Sun Dec 28 2025

Pulses of northerly swell will continue to move through the
region, supporting a continued high likelihood of life-
threatening rip currents along exposed shorelines. As a result, a
High Rip Current Risk remains in effect through Monday for north-
and Atlantic-facing beaches of Puerto Rico, including Culebra, as
well as St. Thomas and St. John. Similar rip current conditions
are expected to persist into midweek, with a gradual improvement
late in the week.

Breaking waves are expected to remain around 6 feet at north-
facing beaches. Rip currents may be strong and difficult to
escape, especially at unguarded beaches. Beachgoers are urged to
avoid entering the water at exposed beaches and to follow all
local beach flags and safety guidance.

&&

.FIRE WEATHER...
Issued at 420 AM AST Sun Dec 28 2025

Drying conditions continue, especially across southern Puerto
Rico. No rainfall is expected today, and no effective rain-makers
are anticipated through at least mid to late week, allowing fuels
to continue drying. Fire danger remains low today, and no active
fires are reported or identified across the islands. KBDI values
continue to trend upward, with recent readings near 545 at Cabo
Rojo and 509 at Camp Santiago, indicating increasing fuel dryness
and approaching fire weather headline thresholds (around 550).
Periods of low relative humidity, combined with moderate breezes
and occasional stronger trade-wind gusts, may briefly enhance fire
spread potential. Overall fire danger remains low, but continued
drying warrants close monitoring, particularly across southern
Puerto Rico.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
512 AM AST Mon Dec 29 2025

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

.KEY MESSAGES...
Issued at 420 AM AST Mon Dec 29 2025

* Pulses of a fading, long-period northerly swell will continue to
spread, maintaining a high risk of life-threatening rip currents
along the north-facing beaches of Puerto Rico, Culebra, St.
Thomas, and St. John through at least Tuesday afternoon. The risk
is expected to remain from low to moderate thereafter.

* Fair weather conditions and cooler than normal temperatures will
prevail through Tuesday across Puerto Rico and the U.S. Virgin
Islands.

* An increase in moisture and marginal instability is expected
from New Year’s Eve through the end of the week. As a result,
rain chances are expected to increase across the forecast area.
Forecast timing uncertainty remains high, continue to monitor
forecast updates.

&&

.Short Term(Today through Wednesday)...
Issued at 420 AM AST Mon Dec 29 2025

Skies remain mostly clear across much of the area, with some
clouds over the northern U.S. Virgin Islands, where a few isolated
showers were observed earlier. Rainfall has been minimal.
Temperatures have already dropped into the mid-50s across higher
elevations and the low-60s across lower elevations, with many
locations cooler than last night, and may continue to fall a few
degrees as the night progresses. Patchy fog has been reported in a
few areas, including near Mercedita Airport, which may briefly
reduce visibility. Winds are light and variable, helping keep
conditions calm overnight.

A broad surface high over the western–central Atlantic will
maintain light to moderate easterly winds, gradually veering
tonight and becoming east-southeasterly on Tuesday. A persistent
mid-level ridge will continue to promote subsidence and relatively
dry conditions, limiting overall shower coverage. Most shower
activity during this period will occur as brief, isolated trade-
wind showers, favoring exposed east-facing coastal areas and the
U.S. Virgin Islands, mainly during the nighttime and early morning
hours. In addition, isolated afternoon convection cannot be ruled
out, primarily over the interior to northwestern Puerto Rico, driven
by local effects. Overall, shower probabilities will remain low
to locally moderate (around 30–40 percent), with brief rainfall
and long dry breaks. Temperatures will remain relatively cool
during this period, although it marks the beginning of a subtle
warming trend, and no weather-related hazard risks are expected
across inland areas.

From Tuesday night into Wednesday, weather conditions begin to
change as a short-wave trough approaching from the western
Caribbean allows moisture to increase. Expect scattered to at
times numerous showers on Wednesday, with locally heavy rain
possible, mainly across western and interior Puerto Rico. Isolated
thunderstorms may develop, primarily over the west, though a few
could occur farther east if conditions allow; however, drier air
lingering over eastern Puerto Rico and the U.S. Virgin Islands may
limit thunderstorm development. As a result, flooding and
lightning risks increase during the day, with conditions gradually
improving late Wednesday night as the wetter pattern moves away.
Temperatures will remain on the cool side with a slight warming
trend.

&&

.Long Term(Thursday through Monday)...
Issued at 420 AM AST Mon Dec 29 2025

A shortwave trough is expected to swing across the Northeast
Caribbean by Thursday (New Year's Day), followed by an amplifying
mid- to upper-level trough over the region through Friday. This
pattern will promote increased instability and a more unsettled
weather regime, especially as a frontal boundary and associated pre-
frontal trough approach the area late Thursday night into Friday. At
the surface, a high-pressure system over the central Atlantic will
maintain an east to east-southeast low-level wind flow through early
next week.

The most favorable window for widespread rainfall appears to be
between Thursday afternoon and Friday evening. However, model
guidance continues to show timing discrepancies regarding both the
onset and departure of the most active period. Rainfall could begin
as early as early Thursday morning and linger into early Saturday
morning. At this time, the highest confidence for widespread shower
activity is from Thursday afternoon into Friday, when periods of
moderate to heavy rain and thunderstorms are most likely. Another
negative factor for the formation of widespread activity could be
the available moisture over the region, where we observed another
discrepancy in the model guidance.

By Saturday, the region will transition to the subsident side of the
mid- to upper-level trough as it lifts eastward, with subsidence
gradually increasing. This will result in a decreasing trend in
shower and thunderstorm coverage and intensity through the weekend.
Although passing showers will remain possible Saturday into Sunday,
vertical development will be limited as a mid- to upper-level ridge
builds over the area.

Late Sunday night into Monday, another shortwave trough is forecast
to approach the region, increasing mid- to upper-level instability.
This may lead to a gradual uptick in shower activity, with the
trough aloft expected to further amplify by Monday night into
Tuesday, potentially signaling a return to more unsettled conditions
early next week.

&&

.AVIATION...
(06Z TAFS)
Issued at 420 AM AST Mon Dec 29 2025

Mainly VFR conds exp at all TAF sites thru 24 hrs. Brief -SHRA and
SCT cigs FL025–060 psbl nr USVI sites thru 29/13Z and aft SHRA
near TJPS/TJBQ. Ops impacts mnml. Winds lgt/vrb, bcmg E–NE 8–12 kt
btw 29/13–22Z, then lgt/vrb aft 29/22Z.

&&

.MARINE...
Issued at 420 AM AST Mon Dec 29 2025

A surface high-pressure moving eastward from the Western to Central
Atlantic, interacting with the remnants of an old frontal boundary,
will create light easterly wind flow across the region through
Tuesday. By midweek, an eastward-moving frontal boundary and a high-
pressure system building across the Central Atlantic will lead to a
moderate east-to-east-southeast wind flow, increasing the chance of
showers and thunderstorms. Pulses of long-period northerly swells
will also continue to spread across the Atlantic Waters and Caribbean
Passages through the middle of the week. Small craft operators
should exercise caution, especially in exposed Atlantic waters and
Caribbean passages.

&&

.BEACH FORECAST...
Issued at 420 AM AST Mon Dec 29 2025

Pulses of a fading, long-period northerly swell will continue to
spread across the local waters, maintaining a high risk of life-
threatening rip currents along the north-facing beaches of Puerto
Rico, Culebra, St. Thomas, and St. John through at least Tuesday
afternoon. As a result, a Rip Current Statement remains in effect
through that period. A low to moderate rip current risk is expected
from midweek through the weekend. Even when the rip current risk is
low, life-threatening rip currents can still occur near groins,
jetties, reefs, and piers. Beachgoers should exercise caution at all
times.
&&

.FIRE WEATHER...
Issued at 420 AM AST Mon Dec 29 2025

Drying conditions continue, especially across southern Puerto
Rico, where minimum relative humidity has fallen below 40% for a
second consecutive day, with some locations dropping into the 20s
to 30s. Winds remain light, limiting fire spread at this time.
KBDI values continue to increase, with Cabo Rojo exceeding fire
danger thresholds (above 550) and Camp Santiago approaching
similar levels, indicating increasingly dry fuels. While no
significant fire weather threat is expected today, continued
drying through mid to late week warrants close monitoring,
particularly as stronger winds are possible Friday into Saturday,
which could elevate fire spread potential if dry conditions
persist.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
405 AM AST Tue Dec 30 2025

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

.KEY MESSAGES...
Issued at 401 AM AST Tue Dec 30 2025

* Hazardous coastal conditions will persist across the northern
coastal areas of Puerto Rico, Culebra, and St. Thomas, where a
high risk of rip currents remains in effect.

* Easterly wind flow will return today; therefore, more
seasonable temperatures are expected today and tonight.

* Puerto Rico and the U.S. Virgin Islands:
For tomorrow, the last day of 2025, a more unsettled weather
pattern is forecast with the arrival of moisture from a frontal
boundary and added instability from an upper-level trough.

&&

.Short Term(Today through Thursday)...
Issued at 401 AM AST Tue Dec 30 2025

Skies will remain mostly clear to partly cloudy today across much
of the forecast area, as the overall pattern remains similar to
the past several days. Ridging aloft with dry mid-levels will
continue to promote relatively stable weather conditions. At the
surface, high pressure over the central Atlantic will continue to
shift eastward, resulting in winds veering from east-northeast to
a more southeasterly component, remaining mostly light to
moderate. These southeasterly winds will persist across the region
through the short- term forecast period. Only isolated brief
showers are expected, mainly over windward coastal areas during
the morning hours and across the western interior of Puerto Rico
during the afternoon due to local effects, as well as over the
surrounding waters at times. Temperatures will remain slightly
below normal, resulting in pleasant conditions across the islands
once again.

From Wednesday into Thursday, weather conditions will become more
variable as a deepening polar trough moves over the region,
enhancing dynamics aloft. Model guidance continues to indicate
falling mid-level heights and 500 mb temperatures dropping to around
-9 to -10 C. This will result in steeper low- to mid-level lapse
rates and a more favorable environment for convective development.
At lower levels, a surge of tropical moisture is expected to arrive,
with precipitable water values increasing to near 1.8 to 2.0 inches
and 700-500 mb relative humidity values rising well above 2 standard
deviations above climatological normals. Despite the increasingly
favorable dynamic setup, guidance remains consistent in keeping the
highest moisture content and more organized convective activity
focused west of the local islands, particularly over Hispaniola and
the Mona Passage. As a result, shower and thunderstorm coverage over
Puerto Rico and the U.S. Virgin Islands may not be as widespread,
with much of the activity favoring the waters west and northwest of
Puerto Rico.

Still, periods of shower activity are expected across the area.
Afternoon convection will be possible over the western and interior
sections of Puerto Rico, particularly on Thursday, driven by the
combination of favorable dynamics aloft, diurnal heating, and local
effects. Additionally, nighttime and early morning trade wind
showers, along with isolated thunderstorms developing over the
regional waters, could affect coastal areas, particularly along the
western half of the CWA. Brief heavy rainfall, gusty winds, and
isolated lightning strikes will be possible with stronger
thunderstorms, although widespread activity is not anticipated.

Overall, the short-term period will feature a transition from
today’s relatively stable and pleasant conditions toward a more
unsettled pattern by mid to late week, with increasing moisture and
enhanced instability aloft, while the highest impacts are expected
to remain mainly over the surrounding waters.

&&

.Long Term(Friday through Tuesday)...
Issued at 401 AM AST Tue Dec 30 2025

An unstable weather pattern will persist on the first day of the
long term, as the main weather pattern is dominated by a mid- to
upper-level trough. This upper-to mid-level feature will create a
very unstable weather pattern, enhancing colder temperatures at
500 MB, ranging from -8 to 9 degrees. Meanwhile, at the surface,
moisture from a sinking frontal boundary over the Caribbean and
instability from the pre-frontal trough will align perfectly with
the upper instability, increasing the frequency and coverage of
showers during the day. Given the variability of winds due to
weakening of the pressure gradient resulting from the surface pre-
frontal trough, the coverage and movement of showers will be slow
and widespread across the mountain sections. Upper conditions
will rapidly improve as the subsidence side of the upper-level
trough moves eastward, and a more stable condition will dominate.
At 500 MB, a ridge will move in, warming temperatures from -9 to
-5 degrees. Stable conditions will persist from Saturday into
Monday; however, at the surface, shallow patches of moisture
dragged by the east-southeasterly wind flow will allow some
showers in the morning across the eastern side and across the
interior and western Puerto Rico for the afternoon. There are some
discrepancies in the amount of available moisture (relative
humidity %) on those days, with the ECMWF calling for a wetter,
more seasonal pattern.

On Tuesday again, weather conditions will deteriorate as another
upper-level trough moves into the Caribbean. Combined with the
instability, values of Relative humidity between 700 and 300 MB
show an increase in moisture, which will induce a more showery
pattern.

&&

.AVIATION...
(06Z TAFS)
Issued at 401 AM AST Tue Dec 30 2025

Mainly VFR conds exp across all TAF sites thru the fcst pd. Brief
- SHRA/VCSH psbl at times, mainly at TJSJ/TIST/TISX, with SCT-BKN
cigs btw FL030–FL060 at times. Any VIS/CIG reductions expected to
be brief. Winds lgt/vrb ovrngt, bcmg ESE–SE at 8–12 kt aft 14Z,
then diminishing again aft 23Z.

&&

.MARINE...
Issued at 401 AM AST Tue Dec 30 2025

A surface high pressure system moving eastward from the western
into the central Atlantic, interacting with the remnants of an old
frontal boundary, will maintain a light easterly wind flow across
the region through Tuesday. From late Wednesday into Friday, an
approaching frontal boundary combined with a strengthening high-
pressure system over the central Atlantic will result in a
moderate east-to-east-southeast wind flow, increasing the
potential for showers and isolated thunderstorms and enhancing
localized hazardous marine conditions. During the period, pulses
of long-period northerly swell will continue to propagate across
the Atlantic waters and Caribbean passages through the middle of
the week. Small craft operators are urged to exercise caution,
particularly across the exposed Atlantic waters and Caribbean
passages.


&&

.BEACH FORECAST...
Issued at 401 AM AST Tue Dec 30 2025

A long-period northerly swell will continue to propagate across
the northern regional waters, resulting in a persistent high risk
of dangerous rip currents along north-facing beaches of Puerto
Rico, Culebra, St. Thomas, and St. John. Therefore, a Rip Current
Statement will remain in effect through at least Tuesday
afternoon. Recent data from buoy 41043, located about 170 nautical
miles north of San Juan, indicate another pulse of northerly
swell arriving across the islands, with wave heights up to 6 feet
and periods near 13 seconds. This swell energy will maintain
breaking waves along the northern coastal areas between 6 and 8
feet, with occasionally higher sets.

Given the forecast conditions, a high rip current risk is expected
to persist through Thursday, with gradual improvement as the
weakening swell dissipates. Nevertheless, even as conditions
improve, hazardous rip currents may still develop near groins,
jetties, reefs, and piers during periods of lower risk. Beachgoers
are advised to exercise caution at all times when entering the
water.