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133
FXCA62 TJSJ 241814
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
214 PM AST Wed Dec 24 2025

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

.KEY MESSAGES...
Issued at 207 PM AST Wed Dec 24 2025

 * A variable weather pattern will persist for the rest of the day
   due to the approach of fragments of moisture from a frontal
   boundary.

 * Pleasant daytime temperatures are forecast for the rest of the
   day and into the night, with slightly colder conditions
   overnight.

 * Pleasant weather conditions across the U.S. Virgin Islands,
   with cloudiness and a few occasionally passing showers.

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

&&

.Short Term(This evening through Friday)...
Issued at 207 PM AST Wed Dec 24 2025

This afternoon through Friday...

Showery conditions will continue across portions of Puerto Rico and
the U.S. Virgin Islands this afternoon as the remnants of a frontal
system continue to influence the region. Recent satellite-derived
advected layer precipitable water (ALPW) fields show a clear
vertical separation in the moisture field associated with this
system. The 700-500 mb ALPW indicates that the mid-level frontal
boundary has already passed over the region, with a noticeable
reduction in moisture aloft over the islands. However, the 850-700
mb layer continues to show enhanced moisture across Puerto Rico and
the U.S. Virgin Islands, consistent with the presence of the
remnants of the associated surface frontal boundary, which is still
moving across northern Puerto Rico and the nearby islands.

This lingering low-level moisture and convergence will support
periods of showers across northern Puerto Rico and the smaller
islands through the afternoon and night hours. In addition, shallow
convective activity is expected across interior and southwestern
Puerto Rico due to some daytime heating interacting with residual
low-level moisture. Given the lack of deep moisture and increasing
mid-level stability, convection will remain shallow in nature.
Rainfall amounts are expected to be generally light to moderate,
though brief heavier showers remain possible. Today continues to
represent the highest flooding concern of the short-term period,
although the risk remains limited. This corresponds to the potential
for ponding of water on roads and in poorly drained or urban areas,
with a low likelihood of small stream flooding. Increasing
northeasterly flow and the progressive nature of the boundary should
limit rainfall accumulations over any one location.

Behind the surface frontal passage, a drier and more stable air mass
will gradually overspread the region on Thursday. This is supported
by decreasing low- to mid-level moisture and increasing subsidence.
Temperatures will  trend near or slightly below climatological
normals, resulting in more pleasant conditions across the islands.

By Thursday night into early Friday morning, clearing skies, lighter
winds, and cooler temperatures could favor patchy fog development,
particularly across valleys and interior sections of Puerto Rico.
Localized visibility reductions may impact early morning travel,
especially in low-lying and sheltered areas. Motorists should
exercise caution, reduce speeds, and use low-beam headlights where
fog develops. Friday is expected to remain mostly fair, with limited
shower activity and continued comfortable temperatures as the post-
frontal air mass becomes established.


&&

.Long Term(Saturday through next Tuesday)...
Issued at 207 PM 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...
(18Z TAFS)
Issued at 207 PM AST Wed Dec 24 2025

SHRA/VCSH to persist across PR and USVI through tonight as frontal
remnants linger. Prevailing VFR at most terminals, but brief MVFR
vis/cigs possible in SHRA. NE winds 10-15 kt with gusts 20-25 kt.
Aft 25/14Z, decreasing SHRA and improving conditions as drier air
overspreads the area. VFR to dominate.&&

.MARINE...
Issued at 207 PM AST Wed Dec 24 2025

Deteriorated marine conditions persist as a series of surface
high-pressure systems move across the Atlantic, and frontal lows
will continue to move across the Atlantic. This energy will
maintain moderate to locally fresh northeast winds through at
least Wednesday. A long-period northerly swell generated by a
frontal low will persist across the offshore Atlantic waters,
resulting in choppy to rough seas and hazardous conditions for
small craft. As a result, a Small Craft Advisory remains in effect
for the offshore Atlantic waters and the Anegada Passage through
Thursday midnight while seas of up to 5 feet persist across the
remaining local waters, especially across the Caribbean waters.

&&

.BEACH FORECAST...
Issued at 207 PM AST Wed Dec 24 2025

Deteriorating coastal conditions are still expected over the next
few days, 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 late afternoon on Thursday. For more
details, please consult the Coastal Hazard Message (CFWSJU).

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Thursday night for PRZ001-002-
     005-008-010-012.

     High Surf Advisory until 6 AM AST Thursday for PRZ001-002-005-
     008.

VI...High Rip Current Risk through late Thursday night for VIZ001.

AM...Small Craft Advisory until midnight AST Thursday night for
     AMZ711-712-716-723-741-742.

&&

$$

SHORT TERM & AVIATION...CVB
MARINE,BEACH FORECAST & KEY MESSAGES...LIS

NWS SJU Office Area Forecast Discussion