923
FXCA62 TJSJ 160830
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
430 AM AST Fri Jan 16 2026

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

.KEY MESSAGES...
Issued at 352 AM AST Fri Jan 16 2026

 * Quiet morning today with a few trade wind showers and increase
   rainfall activity by the afternoon hours along the west
   resulting in wet pavement and low- lying flooding.

 * A strengthening to a moderate breeze is forecast by Friday
   afternoon into the weekend. Please secure outside objects.

 * An increase in rip current risk is forecast for the northern,
   exposed beaches.

&&

.Short Term(Today through Sunday)...
Issued at 352 AM AST Fri Jan 16 2026

Overall conditions were warmer than normal, with slightly cooler
temperatures across windward areas, where passing showers were
observed overnight. Skies remained variably cloudy, dominated by mid-
 to upper-level cloud cover. Shower activity was limited, with no
significant rainfall accumulations reported. Winds were generally
from the east-southeast, remaining light to calm and variable over
land.

Today, conditions start relatively quiet this morning, with a few
trade-wind showers over windward areas, then transition as east-
southeasterly winds and daytime heating take hold. Warmer-than-
normal temperatures are expected, with highs reaching the upper 80s
across lower elevations of northern and western Puerto Rico. By the
afternoon, scattered to locally numerous showers will develop mainly
across western to southwestern Puerto Rico, with a chance of
isolated thunderstorms. Impacts should remain limited, with brief
ponding and localized minor flooding possible in western Puerto
Rico, along with a low lightning risk.

From tonight through Sunday, low-level winds will strengthen as a
building surface high over the North Atlantic tightens the pressure
gradient across the region, with passing easterly (trade-wind)
disturbances modulating conditions. Winds will back to east-
northeasterly tonight, then veer back to easterly on Saturday and
Sunday, supporting a gradual cooling trend. The first and most
prominent disturbance will bring a wetter band early Saturday to the
U.S. Virgin Islands, Culebra, Vieques, and eastern Puerto Rico,
followed by afternoon shower development across western Puerto Rico.
From Saturday night through Sunday, a trade-wind-driven pattern
persists with fresh to locally strong winds and passing showers,
while conditions become more stable by Sunday afternoon; overall
hazards include localized ponding and minor flooding mainly Saturday
across northeastern and western Puerto Rico, and increasing wind
impacts beginning tonight and persisting through the weekend,
especially across exposed and coastal areas.

&&

.Long Term(Monday through Friday)...
Issued at 352 AM AST Fri Jan 16 2026

The latest model guidance indicates a transition toward a wetter
and more unsettled pattern beginning Monday and continuing through
much of the workweek. Precipitable water values are forecast to
increase to around 1.75 inches, which is above normal for this
time of year and supportive of additional rainfall activity,
particularly by midweek. From Monday through Wednesday, a
subtropical jet streak near 250 mb will enhance upper-level
divergence and support the development of an induced surface
trough, resulting in higher shower coverage across the forecast
area as easterly to northeasterly low-level flow becomes
established by midweek.

Tuesday may see some variability as guidance hints at a pocket of
drier air moving south of the region. At this time, it remains
unclear whether this drier air will reach the forecast area, and
its potential influence on rainfall will continue to be monitored.

Wednesday currently appears to be the wettest and most unstable day of
the long-term period. 500 mb temperatures near -7 degrees Celsius
will promote greater vertical growth of convection, increasing
instability and the potential for isolated thunderstorms,
particularly during the afternoon hours. In addition, weakening
low-level winds may allow showers to persist over the same areas
for extended periods, potentially elevating the risk of localized
flooding.

From Monday onward, 925 mb temperatures are expected to remain
above normal. When combined with the increasing moisture,
conditions may feel warmer than they actually are. While rainfall
coverage and intensity may vary at times, each afternoon carries
at least a limited flooding risk, primarily due to ponding of
water on roads and in poorly drained locations.

&&

.AVIATION...
(06Z TAFS)
Issued at 352 AM AST Fri Jan 16 2026

Mainly VFR expd across all TAF sites thru the fcst pd. Psg TW SHRA
may affect TJSJ & USVI terminals at times, with brief MVFR vsby/cigs
psbl in heavier SHRA. Aftn SHRA w/ iso TSRA may impact TJBQ
(16/1722Z), again with brief MVFR psbl. Activity diminishes aft
sunset. Sfc winds lgt/vrb early, bcmg ESE 1015 kt w/ aftn gusts,
then around 812 kt aft 16/22Z. No sig or prolonged avn impacts
expd.

&&

.MARINE...
Issued at 352 AM AST Fri Jan 16 2026

Surface winds continue from the southeast through later today. On
Saturday, strengthening east to northeast winds, and the arrival
of a long- period northerly swell will likely result in choppy to
rough seas, leading to hazardous marine conditions during the
weekend into the upcoming workweek. A Small Craft Advisory will be
in effect for the Offshore Atlantic waters from late Saturday
into Monday. Mariners are urge to exercise caution across the
offshore Atlantic waters and the local passages as we head into
the weekend.


&&

.BEACH FORECAST...
Issued at 352 AM AST Fri Jan 16 2026

The moderate risk of rip currents along all the northern-exposed
beaches in Puerto Rico and the U.S. Virgin Islands will remain
favorable through Friday. Conditions will deteriorate Saturday and
Sunday, when energy from a northerly swell moves in and winds
increase, resulting in breaking waves along all the north and
northeast coasts of Puerto Rico, including Culebra. As a result, a
high risk of rip current is forecast for the upcoming weekend.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...Small Craft Advisory from 2 PM Saturday to 2 PM AST Monday for
     AMZ711.

&&

$$

SHORT TERM/AVIATION...ICP
LONG TERM/MARINE/BEACH FORECAST...MMC

NWS SJU Office Area Forecast Discussion