Your Number One Source for Real-Time Puerto Rico Weather & Hurricane Tracking Updates

016
FXCA62 TJSJ 210908
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
508 AM AST Wed Jan 21 2026

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

.KEY MESSAGES...
Issued at 508 AM AST Wed Jan 21 2026

* Breezy to windy conditions will continue today, which could
  cause outdoor items to be blown around or damaged.

* Choppy to rough seas will result in hazardous marine and coastal
  conditions. Small Craft Advisories and High Rip Current
  Statements will likely remain in effect through the rest of the
  workweek.

* Fast moving trade wind showers will continue, resulting in
  slippery road conditions and ponding of water in low-lying and
  poor drainage areas. Afternoon showers likely to develop over
  interior to western PR.

* A surface trough moving westward across the region from late
  tonight into Friday will gradually deteriorate weather
  conditions, increasing the potential for showers and isolated
  thunderstorms.

&&

.Short Term(Today through Friday)...
Issued at 508 AM AST Wed Jan 21 2026

A variable weather pattern prevailed during the night into the early
morning hours. Satellite and radar imagery showed patches of
cloudiness and frequent passing showers across the local waters,
briefly affecting the eastern sections of the main islands and the
U.S. Virgin Islands. Around 3:00 AM, a moderate shower moved across
the San Juan metropolitan area, tracking westward and affecting
northern municipalities. This shower activity was accompanied by
gusty winds, according to unofficial weather stations, with gusts
reported up to 21 knots. Overnight low temperatures ranged from the
mid to upper 70s across coastal areas to the low 60s across the
interior.

A broad surface high pressure over the Central Atlantic will be the
main weather feature today, resulting in breezy conditions with east
winds up to 15 knots.   Under this pattern, patches of moisture
embedded in the winds will result in cloudiness and frequent showers
moving in and out of the region. Since breezy conditions remain,
minimal rainfall accumulations are expected from fast-moving
showers. Therefore, for the rest of the day, residents and visitors
should expect good periods of sunshine across western sections with
passing showers across eastern sections of Puerto Rico and the U.S.
Virgin Islands. In the afternoon, some brief showers are forecast
across some interior areas with no flooding threat.

The weather pattern is forecast to become wetter and marginally
unstable from Thursday into Friday as an induced surface trough
associated with a cut-off low located well east of the islands moves
across the region. According to the latest model guidance, moisture
is forecast to increase, with precipitable water values rising from
around 1.5 inches on Thursday to near 1.70 inches on Friday, above
climatological normals. On Thursday, moisture should remain mostly
shallow; however, as the day progresses, 850-500 MB relative
humidity values show deep moisture moving into the islands. The
presence of abundant moisture will combine with marginally unstable
conditions at the mid and upper levels due to a strong jet streak
over the area, providing upper divergence, and marginally colder
temperatures at 500 MB (-7 to -8 degrees).  Given the expected
conditions, residents can expect an increase in morning showers,
followed by more organized showers across the mountain and western
sections. Surface winds will remain breezy; however, with the
passage of the induced surface trough, winds are expected to
decrease to around 15 knots on Thursday. As a result, residents and
visitors can expect showers and isolated thunderstorms, which should
bring periods of heavy rainfall and gusty winds, resulting in
ponding of water over roadways, urban areas, and poorly drained
areas, with minor flooding in these areas. Additionally, reduced
visibility and lightning cannot be ruled out. Therefore, for the
hazards on Thursday into Friday, a flooding and lightning risk will
remain limited.

&&

.Long Term(Saturday through Wednesday)...
Issued at 508 AM AST Wed Jan 21 2026

Increased moisture and instability will carry from the short term
period into Saturday, as the moisture field from the disturbance
continues over the region promoting above seasonal precipitable
water (PWAT) values (1.50 to near 2 inches). Saturday looks to be
the wettest day in the long term period, with advective showers
steered by easterly flow and convective afternoon showers over
interior to western PR. Improved weather conditions are forecast
from late Saturday through Sunday as the atmospheric disturbance
and moisture field moves westward and out of the region and drier
air advects into the area. Patches of drier and moist air will
then promote seasonal (

NWS SJU Office Area Forecast Discussion