National Weather Service Today's Weather Impact Levels

256
FXCA62 TJSJ 120907
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
507 AM AST Mon Jan 12 2026

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

.KEY MESSAGES...
Issued at 507 AM AST Mon Jan 12 2026

* Localized flooding is possible from passing showers that may
  bring brief, heavy rain, especially overnight and in the
  mornings in windward areas of Puerto Rico and U.S. virgin
  Islands, and in the afternoons in western Puerto Rico. This
  could lead to ponding on roads and isolated flooding in urban
  areas and small streams.

* Moderate risk of rip current: life-threatening rip currents are
  expected along the northwest, north, and east-facing beaches of
  Puerto Rico and the U.S. Virgin Islands through the workweek.
  The risk may increase this weekend, becoming high due to
  stronger winds and a northwesterly swell.

* Comfortable to near-seasonal temperatures will continue through
  midweek across Puerto Rico and the U.S. Virgin Islands, with
  cooler nights through Tuesday morning, followed by a warming
  trend and above-normal temperatures expected toward the end of
  the week.

&&

.Short Term(Today through Wednesday)...
Issued at 507 AM AST Mon Jan 12 2026

Mainland Puerto Rico experienced generally quiet weather conditions
through most of the overnight hours. Meanwhile, a trade wind
perturbation brought passing showers across the U.S. Virgin Islands
overnight, with some activity briefly reaching eastern Puerto Rico;
however, most of the shower activity remained over the surrounding
coastal waters. Winds were mainly from the east to east-northeast at
5 to 10 mph. Skies remained mostly clear across mainland Puerto
Rico, while partly to mostly cloudy conditions prevailed over the
U.S. Virgin Islands. Overnight and early morning temperatures ranged
from the low 70s to the upper 60s along the coast, dropping to the
upper 50s to the low 60s across the interior valleys and mountainous
regions.

As a mid- to upper-level trough continues to move eastward into
the central Atlantic, a mid- to upper-level ridge is expected to
gradually build over the northeastern Caribbean over the next few
days. At the surface, however, a weak induced trough will maintain
periods of showery weather across Puerto Rico and the U.S. Virgin
Islands today and tomorrow. This pattern will keep total
precipitable water values near or briefly above typical January
levels, as suggested by model guidance and supported by satellite
observations.

Under this weather pattern, residents and visitors will observe
periods of sunshine; however, the advection of clouds within the
trade wind flow will result in passing showers. Periods of moderate
to locally heavy rainfall are most likely during the overnight and
early morning hours across the U.S. Virgin Islands and windward
areas of Puerto Rico, followed by limited afternoon convection
mainly across western Puerto Rico. Moisture is expected to decrease
somewhat by Tuesday, resulting in fewer showers. However, on
Wednesday, another trade wind perturbation is forecast to increase
available moisture once again. Enhanced by low-level convergence and
local orographic effects, this could lead to ponding of water on
roads and in poorly drained areas, particularly across eastern
Puerto Rico and the U.S. Virgin Islands during the afternoon and
evening hours.

Overall, a limited risk of flooding is expected, though isolated
instances of urban and small stream flooding cannot be ruled out on
any given day. Residents and visitors are encouraged to stay
informed by following the latest forecasts and updates in case
conditions change.

&&

.Long Term(Thursday through Monday)...
Issued at 507 AM AST Mon Jan 12 2026

During Thursday, a deep-layer mid to upper-level trough will be
well east of the Lesser Antilles, while a mid level ridge persists
over the northeastern Caribbean. Trade wind showers will continue
to affect the region on Thursday, with limited afternoon convection
expected across western and northwestern Puerto Rico. On Friday,
model guidance suggests a frontal boundary will remain north of
the region, while a pre-frontal trough may enhance moisture
convergence and atmospheric instability, supporting a wetter
pattern on Friday. At this time, Friday appears to present the
highest rainfall potential, with a limited flood risk mainly
across western Puerto Rico during the afternoon hours. Isolated
thunderstorm activity cannot be ruled out as mid-level temperatures
cool, with 500 mb temperatures decreasing from near -4 degrees C
on Wednesday to around -7 degrees C by latter part of the week.
Precipitable water values are forecast to range between 1.5 and
1.8 inches from Thursday through Saturday, near to above
climatological normal for this time of year, with peak moisture
expected on Friday.

Low-level winds will generally remain from the east to southeast
at 10 to 15 mph with gusts up to 20 mph through Friday, then shift
to the east-northeast from Saturday through Monday while increasing
to 15 to 25 mph with gusts up to 30 mph. Breezy to locally windy
conditions are anticipated, particularly on Saturday, which may
result in loose outdoor items being blown around, especially
across exposed and coastal areas.

From Sunday through Monday, precipitable water values are expected
to decrease to between 1.1 and 1.5 inches, with patches of near-
average moisture moving across the region, promoting variable but
seasonable weather conditions with passing trade wind showers and
limited convective development.

Ensemble guidance continues to indicate slightly above-normal
temperatures across Puerto Rico and the U.S. Virgin Islands
throughout the long-term period.

&&

.AVIATION...
(06Z TAFS)
Issued at 507 AM AST Mon Jan 12 2026

VFR conds expected across the terminals today. Passing -SHRA/SHRA
will affect TJSJ, TIST, and TISX at times, with additional activity
possible near TJPS during the afternoon, producing brief MVFR
conditions. There is a limited chance of -TSRA across interior and
western Puerto Rico between 16Z-23Z. A similar pattern, with less
activity, is expected on Tuesday. Winds will be calm to light and
variable overnight, becoming ENE-E at 10-15 kt after 13Z with
higher gusts and local sea breeze variations.

&&

.MARINE...
Issued at 507 AM AST Mon Jan 12 2026

A surface high pressure moving eastward across the central Atlantic,
combined with a weak surface trough northeast of the region, will
maintain gentle to moderate east to northeast winds through mid-
week, then shifting from the east to southeast by Thursday and
Friday. This pattern will support passing trade-wind showers, mainly
across the Atlantic waters, with occasional showers also moving
through the Caribbean passages. By the end of the week into the
weekend, strengthening northeasterly winds and the arrival of a
long-period northerly swell will likely result in choppy and
potentially hazardous marine conditions. Mariners are advised to
continue monitoring the forecast.

&&

.BEACH FORECAST...
Issued at 507 AM AST Mon Jan 12 2026

The moderate risk of rip currents continues today for the
northwestern, northern and eastern beaches of Puerto Rico, as well
as Culebra and USVI, with breaking waves around 4 feet. Similar
conditions are expected to persist most of the workweek. A
moderate risk indicates that life-threatening rip currents are
possible within the surf zone, and beachgoers should exercise
caution at all times.

A low risk will prevail across southern, more protected areas;
however, life-threatening rip currents can still occur near
groins, jetties, reefs, and piers even when the overall risk is
low. For more location-specific information, continue to monitor
weather.gov/beach/sju.

By next weekend, conditions will likely deteriorate due to
increasing winds and the arrival of a long-period northerly swell,
with the potential for a high risk of rip currents to return
across most local beaches of Puerto Rico and USVI.

&&

.FIRE WEATHER...
Issued at 507 AM AST Mon Jan 12 2026

Recent wetting rains have provided temporary relief across fire-
prone areas in southern Puerto Rico, however, longer-term dryness
and rainfall deficits are expected to persist. While KBDI values
have decreased at some sites, fuels remain locally elevated,
especially across southern Puerto Rico and Vieques, and isolated
wildfire activity continues to be detected by satellite.
Northeasterly winds may support additional showers through
tomorrow, but winds are expected to shift to east-southeast from
Wednesday through Friday. This will favor drier conditions, with
pockets of below-normal moisture possible during peak fire weather
hours. Although early morning rainfall may help delay fire
potential on some days, locally elevated fire danger remains,
warranting continued monitoring.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...None.
&&

$$

CAM/YZR

NWS SJU Office Area Forecast Discussion