National Weather Service Today's Weather Impact Levels

140
FXCA62 TJSJ 121850
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
250 PM AST Fri Dec 12 2025

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

.KEY MESSAGES...
Issued at 250 PM AST Fri Dec 12 2025

* Choppy to rough seas and life-threatening rip currents are
  expected to continue through the weekend.across the islands,
  particularly from Friday through Sunday.

* Breezy to locally windy conditions are expected across the
  islands this weekend.

* Patches of moisture from the east will reach the islands later
  tonight into tomorrow and then tomorrow evening into early Sunday,
  increasing passing shower activity. Limited afternoon convection
  possible over northwest PR.

* For the U.S. Virgin Islands, passing showers will increase in
  frequency later tonight through Saturday.

* A nearby frontal system over the western Atlantic and an
  associated upper level trough will promote more unstable
  conditions to start the next workweek.
&&

.Short Term(This evening through Sunday)...
Issued at 241 PM AST Fri Dec 12 2025

During the early morning hours, a surface disturbance moved
across the region, producing isolated showers over the windward
sectors of Puerto Rico. Rainfall totals generally reached around
half an inch, with isolated areas receiving up to 1 inch across
northern and eastern Puerto Rico. Radar estimates indicated only
minimal accumulations across the U.S. Virgin Islands. Afterwards,
mainly fair weather prevailed, as shown by radar and satellite
imagery, with a drier airmass settling over the region. The 12Z
sounding measured 1.5 inches of precipitable water, but more
recent satellite data indicates values closer to 1.00 inch.
Daytime highs reached the mid to upper 80s, with some coastal
stations reporting low 90s. Across the higher elevations of Puerto
Rico, temperatures remained in the 70s to low 80s. Winds became
breezy, with several coastal stations recording gusts between 25
and 30 mph out of the east to southeast.

The short-term forecast remains on track, with variable weather
conditions and breezy winds expected to persist through the
weekend. Surface high pressure will strengthen and linger over the
central Atlantic, supporting increasing east to southeasterly
winds and breezy to locally windy conditions across the islands,
at least through next Sunday. Model guidance continues to indicate
increasing moisture due to disturbances moving through the trade
winds, one tonight and another from Saturday evening into early
Sunday.

During the daytime hours each day, lower precipitable waters (PWAT)
values will dominate, fluctuating between below-normal and above-
normal levels. As a result, mainly fair weather is expected, with
only limited shower activity across western Puerto Rico (low chance),
while the U.S. Virgin Islands and the windward sectors of Puerto
Rico will see moderate to high chances of nighttime and early-
morning showers. The highest moisture content, ranging from 1.8 to
2.0 inches (above normal), is expected Saturday afternoon and
night. During this period, there will be a limited flooding risk
across eastern Puerto Rico and the U.S. Virgin Islands, with the
potential for ponding on roads, poor drainage issues, and a low
chance of urban and small-stream flooding. During the rest of the
period, there are no flooding concerns anticipated. A southeasterly
wind pattern will continue to bring warmer air, leading to above-
normal temperatures in the short term. However, the overall heat
threat is expected to remain low for the remainder of the period.

&&

.Long Term(Monday through Friday)...
Issued at 518 AM AST Fri Dec 12 2025

Global models have a wetter solution than previous days with the
approaching frontal system over the western Atlantic and
associated upper level trough promoting more unstable conditions
through first part of the workweek. The 500 mb temperatures are
expected to drop to around -6.5C and the precipitable water
content is expected to remain near 1.75 inches, above normal
levels for most of the period. The mid-to upper-level ridge is now
expected to erode earlier and have little influence in the local
weather conditions. Pooling of normal to above normal moisture
content over the area will lead to weak surface troughs to move
from the east on most days, increasing the chance of showers
between 50-70% each day across the islands, with a slight chance
of thunderstorm development over western PR in the afternoon
hours. However, decided to not include them in the forecast as of
now due to possible model variations.

At the surface, a broad high pressure will linger near and south
of the Azores through the long term period. Meanwhile, a cold
front over the western Atlantic should remain north of the region
early in the forecast. This will promote a southeasterly wind
flow, leading to warmer than normal temperatures before the onset
of afternoon showers. Another surface high pressure is expected to
build behind the front and over the western Atlantic during the
second part of the week, bringing east to northeast trades and
a cooler air mass.

&&

.AVIATION...
(18Z TAFS)
Issued at 250 PM AST Fri Dec 12 2025

VFR conditions for the terminals. E-SE winds at 13-20 kts, with
gusts up to 28 kts through 12/23Z, decreasing after. An increase in
VCSH/-SHRA is forecast during the overnight hours, these can promote
brief MVFR conditions over eastern terminals. As VCSH/-SHRA move
over the region, winds will increase again after around 13/13-14Z to
13-20 kt from the E-SE, with higher gusts and sea breeze variations.

&&

.MARINE...
Issued at 250 PM AST Fri Dec 12 2025

A surface high pressure system will continue to build near the
Azores through the weekend. A weak cold front and another surface
high pressure system will move from the western Atlantic into the
central Atlantic over the next few days. This pattern will promote
moderate to locally fresh east to southeast trade winds across
the local waters. Increasing winds and a long-period northerly
swell will result in choppy to rough seas, mainly across the
Atlantic waters and portions of the Anegada and Mona Passages.
Small Craft Advisories remain in effect at least through tomorrow
morning across the passages and through Sunday afternoon across
the offshore Atlantic waters.

&&

.BEACH FORECAST...
Issued at 250 PM AST Fri Dec 12 2025

A long-period northerly swell and increasing wind waves will
create life-threatening rip currents along the north and east
facing beaches of the islands over the next few days. A Rip
Current Statement remains in effect for the northwest to northeast
beaches of Puerto Rico, including Culebra, as well as St. Thomas
and St. John. Beachgoers are urged to avoid swimming in these
conditions, particularly through the rest of today and Saturday.
The west and south-facing beaches of the islands will experience a
moderate risk of rip currents. For specific location information,
please visit weather.gov/beach/sju.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Saturday afternoon for PRZ001-002-
     005-008.

     High Rip Current Risk through late tonight for PRZ012.

VI...High Rip Current Risk through late tonight for VIZ001.

AM...Small Craft Advisory until 5 PM AST Sunday for AMZ711.

     Small Craft Advisory until 6 PM AST this evening for AMZ712-716.

     Small Craft Advisory until noon AST Saturday for AMZ723.

     Small Craft Advisory until midnight AST tonight for AMZ741.

&&

$$

SHORT TERM...YZR
LONG TERM...DS
AVIATION...MRR

NWS SJU Office Area Forecast Discussion