National Weather Service Today's Weather Impact Levels

905
FXCA62 TJSJ 110912 CCA
AFDSJU

Area Forecast Discussion...CORRECTED
National Weather Service San Juan PR
512 AM AST Thu Dec 11 2025

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

.KEY MESSAGES...
Issued at 442 AM AST Thu Dec 11 2025

* Choppy to rough seas and life-threatening rip currents are
  expected into the weekend.

* For Puerto Rico, passing showers are expected mainly during the
  night/early morning hours across the eastern sections. Followed
  by limited afternoon shower activity over the northwest.

* For the U.S. Virgin Islands, a surge in moisture moving from the
  Anegada Passage will bring showers and some cloudiness today.

&&

.Short Term(Today through Saturday)...
Issued at 442 AM AST Thu Dec 11 2025

Mostly fair conditions persisted during the night hours, with
passing showers moving across the local waters and passages into
portions of eastern Puerto Rico and the U.S. Virgin Islands. Based
on station reports, rainfall accumulations remain low (up to 0.06
inches), except on St. Croix, which received 0.16 inches in 3 hours.
SE winds slightly weak, but isolated stations such as in Utuado,
Aibonito, and Cayey in Puerto Rico reported wind gusts up to 27
mph. In the U.S. Virgin Islands, the Cyril E. King and Henry E.
Rohlsen International Airports, both at St. Thomas and St. John,
respectively, reported 17-20 mph wind gusts. According to local
stations, temperatures were slightly warmer compared to yesterday,
with lower elevations in the low to mid 70s and higher elevations
in the low to mid 60s.

No major changes were introduced to the short-term forecast. The
surface high pressure over the Central Atlantic will continue to
promote southeasterly winds through most of the period, increasing
by Saturday morning and bringing breezy to windy conditions (winds
between 15 - 25 mph, wind gusts up to 35 mph) once again across the
islands. The mid-level ridge lingering northeast of the region
continues to dominate the weather pattern, warming mid-level
temperatures, serving as a cap for deep convection and limiting
cloud growth. Another drier air mass is expected to filter into the
region in the morning hours, lowering the chance of precipitation
across the islands. The latest HIRES models indicate afternoon
convection over portions of northwestern Puerto Rico each day,
though rainfall accumulations are unlikely to pose a flooding risk.
Another disturbance in the trades is expected to arrive this
afternoon, pooling high moisture content for this time of the year.
The latest deterministic guidance of the GFS and ECMWF suggests
Precipitable Water (PWAT) values increasing to seasonal and even
above climatological normals (1.4 and 1.6 inches, with a low chance
of reaching 1.8 inches). The most likely scenario remains, with an
increase in showers over the Caribbean waters moving over
southeastern and eastern portions of Puerto Rico and the U.S. Virgin
Islands for the rest of the day into the night hours, persisting
through Friday morning. Although a widespread flooding risk is not
expected, isolated areas may experience ponding of water over roads
and poorly drained areas. A similar weather pattern is expected on
Friday and Saturday, with another drier air mass filtering on Friday
afternoon (PWAT dropping between 1.0 and 1.2 inches) and another
disturbance arriving by early Saturday, increasing once again shower
activity across the islands and persisting throughout the day.


&&

.Long Term(Sunday through Thursday)...
Issued at 442 AM AST Thu Dec 11 2025

A broad surface high pressure will linger near and south of the
Azores through the long term period. Meanwhile, a cold front is
expected to move early in the workweek over the western Atlantic.
This surface pattern will promote southeasterly winds over the
local area, leading to warmer than normal daytime temperatures
across the islands. Max temps are forecast to range from the upper
80s to low 90s in some of the lower elevations, with heat indices
reaching the low 100s, particularly in western PR.

In terms of weather conditions, a similar weather pattern is
expected early in the period due to the influence of a mid-to
upper-level ridge to the east/northeast of the region. This will
promote fairly stable conditions, with brief patches of moisture
embedded in the trades bringing passing showers across the USVI
and eastern portions of PR during the night. Shallow afternoon
convection is still expected to develop over NW PR, but rainfall
accumulations are not expected to cause flooding concerns.
However, by midweek, an upper level trough will bring SW winds
aloft, and cause a brief weakness at the surface that will allow
for better pooling of moisture over the area as weak surface
troughs move from east to west. This will increase the chance of
showers between 40-60% each day across the islands, with a slight
chance of thunderstorm development over west/northwest PR late in
the afternoon hours.

&&

.AVIATION...
(06Z TAFS)
Issued at 442 AM AST Thu Dec 11 2025

Mainly VFR conds across most TAF sites, with brf prds of MVFR conds
over TIST due to -RA through 11/13z. VCSH is expect by 11/18z due
another disturbance from the SE at most terminals through at
least 11/23z, reducing CIGs/VIS and brfly promoting MVFR conds.
Winds from the SE btwn 10-13 kt with gusts up to 23 kt are likely
after 11/13-14z, weakening btwn 5-8 kt around 11/23z.

&&

.MARINE...
Issued at 442 AM AST Thu Dec 11 2025

A surface high pressure will continue to build near the Azores
through the weekend. A weak cold front and another surface high
pressure will move from the western Atlantic into the central
Atlantic during the next few days. This will promote moderate to
locally fresh east to southeast trades across the local waters.
Increasing winds and a long period northerly swell will cause choppy
to rough seas, mostly over the Atlantic offshore waters. Small Craft
Advisory (SCA) conditions are expected across these waters, however,
SCA conditions can spread into portions of the Anegada and Caribbean
waters later this weekend.

&&

.BEACH FORECAST...
Issued at 442 AM AST Thu Dec 11 2025

A long period northerly swell and increasing wind-waves will
cause life-threatening rip currents along the north and east
facing beaches of the islands during the next few days. There is a
Rip Current Statement in effect for the northwest to northeast
beaches of PR, including Culebra, and the northern USVI. Beach
goers are urged to avoid swimming in these conditions, particularly
today and on Friday. The west/southern beaches of the islands
will have a moderate risk of rip currents.

&&

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

VI...High Rip Current Risk from this evening through late Friday
     night for VIZ001.

AM...Small Craft Advisory until 6 PM AST Friday for AMZ711.

&&

$$

SHORT/AVIATION...MNG
LONG/MARINE/BEACH...DSR

NWS SJU Office Area Forecast Discussion