National Weather Service Today's Weather Impact Levels

488
FXCA62 TJSJ 111829
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
229 PM AST Wed Mar 11 2026

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

.KEY MESSAGES...
Issued at 229 PM AST Wed Mar 11 2026

* Frequent passing showers are expected to continue, with
  afternoon showers and isolated thunderstorms possible over
  western Puerto Rico during the afternoon hours, particularly
  today and Thursday.

* Slightly drier trend for Friday and especially Saturday, but
  showers may develop over the western interior of PR during the
  afternoon hours.

* Lighter winds are expected Thursday through early Saturday,
  however, winds are forecast to increase around Saturday night
  into Sunday, leading hazardous marine and beach conditions.

* Across the U.S. Virgin Islands, occasional passing trade wind
  showers will continue, with a drying trend expected by Friday
  and Saturday.

&&

.Short Term(This evening through Friday)...
Issued at 229 PM AST Wed Mar 11 2026

Mostly cloudy skies and scattered showers were observed across
the islands today. As of 1 PM, the Doppler radar estimated between
half to an inch of rain with the heaviest showers. Wind gusts
were between 22 and 32 mph. High temperatures were from the low to
mid- 80s in general across the lower elevations. For the rest of
this afternoon, cloudiness and shower activity will persist over
the western half of PR, while trade wind showers continue to move
at times across the USVI and eastern coastal areas of PR.

In terms of moisture content and shower potential, an upper level
trough and induced low-level trough will continue to promote an
increase in showers through late Thursday/early Friday morning.
Isolated thunderstorms are expected to develop late this afternoon,
and once again on Thursday as the trough pattern promotes an
unstable atmosphere. Urban and small stream flooding is expected
with this activity, particularly on Thursday, as winds decrease and
promote slow-moving showers over the mountain ranges. Strong gusty
winds are also expected with this activity.

Drier air and more stable conditions will gradually filter over the
region late in short-term period. However, lingering moisture
content and the proximity of the short-wave trough aloft will still
cause showers and possible isolated thunderstorms to develop over
the western interior of PR during the afternoon hours.

&&

.LONG TERM(Saturday through Wednesday)...
Issued at 320 AM AST Wed Mar 11 2026

Current model guidance suggests PWAT values around 1.20 to 1.40
inches on Saturday, increasing to around 1.6 inches on Sunday as a
patch of more humid air approaches the area. Favorable conditions for
shower development will continue as a jet stream aloft continues to
promote ventilation to accompany the low level moisture approaching
the area. This can promote vertical shower development and possible
t-storm formation, particularly during afternoon convection over
interior to southwestern PR on Saturday under ENE flow and interior
to northwestern PR under ESE flow Saturday onwards, as well as lines
of showers from the USVI, Vieques and Culebra to ESE PR. Sunday
appears to be the wettest day of the weekend. A broad surface high
will move into the western Atlantic and continue building, promoting
increased wind speeds. 925 mb wind speeds will be above normal,
resulting in breezy to locally windy conditions to start the next
week. For the first half of the next workweek, more stable
conditions will dominate with warmer 500 mb temperatures. This will
serve to limit shower development, however breezy ESE flow will
steer showers and patches of moisture towards windward sectors with
diurnal heating promoting afternoon convective showers over interior
to northwestern PR, as well as lines of showers towards the local
islands. 925 mb temperatures will remain at normal values but under
a general warming trend with less cloud cover.

&&

.AVIATION...
(18Z TAFS)
Issued at 229 PM AST Wed Mar 11 2026

Mainly VFR conditions expected through most of the fcst period.
Locally induced SHRA and possible iso TSTMs over western PR may
lead to tempo MVFR conds thru 11/22z. Elsewhere, trade wind SHRA
will move at times through Thursday morning, causing brief MVFR
cigs, particularly at TIST. The 11/12z TJSJ sounding indicated
east winds up to 24 kt blo 3000ft.

&&

.MARINE...
Issued at 229 PM AST Wed Mar 11 2026

A surface high pressure across the Atlantic will promote mainly
gentle to moderate easterly winds tonight. Seas are forecast to
remain around 4 to 6 feet across offshore waters and passages, as
a result, small craft operators should exercise caution. Improving
marine conditions are forecast toward the end of the week, as
winds are expected to remain gentle to moderate and seas decrease
to between 3 and 5 feet. However, winds are forecast to start
increasing again around Saturday night into Sunday, leading to
rough and choppy seas and likely prompting Small Craft Advisory
conditions from late in the weekend into early next week, with
seas building to around 6 to 8 feet.

&&

.BEACH FORECAST...
Issued at 229 PM AST Wed Mar 11 2026

Life-threatening rip currents are possible tonight along the
north, east, and southeast coastlines of Puerto Rico, Vieques,
Culebra, and the U.S. Virgin Islands as a moderate risk continues.
By Thursday, winds are expected to subside, resulting in improved
conditions, however, the rip current risk will remain moderate
along north and east-facing beaches of Puerto Rico, Culebra, and
St. Croix, and decrease to low elsewhere. The same pattern will
continue through early Sunday.

The risk is forecast to increase to high around Sunday night into
early next week, along with breezy to windy conditions. Residents
and visitors are encouraged to monitor the forecast for any
updates or adjustments. For additional information and location-
specific rip current details, please visit: weather.gov/beach/sju.

&&

.FIRE WEATHER...
Issued at 229 PM AST Wed Mar 11 2026

The KBDI remains above critical fire weather thresholds in Cabo
Rojo (670) and below thresholds in Guanica (520) and Camp
Santiago (390). Around 10 AM AST and noon, surface observations
showed RH values in the low 50s in Cabo Rojo and other areas in
southern areas of Puerto Rico and also in St. Thomas. The rest of
the afternoon, passing showers will continue to move across the
area from time to time; however, drying soils, lower humidity
later in the day and and strong winds will maintain a moderate to
elevated fire danger risk today, particularly for southwestern
Puerto Rico. Tonight into Saturday, winds are expected to become
light to moderate. Additionally, RH values are expected increase
due to the arrival of another patch of moisture into the area. At
this time an RFD will not be issued, but we encourage partners to
continue monitoring conditions in the coming days.

&&

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

$$

SHORT TERM/AVIATION...DS
LONG TERM...MRR
MARINE/BEACH/FIRE...YZR

NWS SJU Office Area Forecast Discussion