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954
FXCA62 TJSJ 130612
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
212 AM AST Thu Aug 13 2026

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

.KEY MESSAGES...
Issued at 212 AM AST Thu Aug 13 2026

- Dry, hazy, and windy through much of Saturday. Saharan dust will
  gradually fade, while stronger winds and drying fuels increase
  fire danger.

- Marine and coastal hazards will rapidly increase. Small Craft
  Advisories begin Thursday night, with a high risk of life
  threatening rip currents Friday into the weekend.

- A wetter pattern returns late Saturday night into Monday as
  moisture associated with Invest 92L arrives. Beneficial rainfall
  is expected, but flooding and lightning risks will increase;
  development remains uncertain.

- Heat Risk will remain limited through Monday, then increase
  later next week as conditions become more favorable for greater
  heat stress.


&&

.Short Term(Today through Saturday)...
Issued at 212 AM AST Thu Aug 13 2026

A significant change toward much drier and increasingly breezy
conditions will take place today as high pressure becomes better
established over the central Atlantic. The tightening pressure
gradient will strengthen easterly trade winds through Saturday.

A very dry and stable air mass will settle across Puerto Rico and
the U.S. Virgin Islands today, with precipitable water falling to
around an inch, well below the lower extreme of the climatological
distribution. This will strongly suppress convection, limiting
rainfall mainly to brief trade-wind showers across windward areas.
A few showers may develop downstream of the islands or over western
Puerto Rico during the afternoons, but significant rainfall and
thunderstorm activity are not expected through Friday.

Moderate Saharan dust will gradually diminish today, although
lower concentrations will linger through Saturday. Breezy to
locally windy conditions will persist, particularly during the
daytime and across exposed coastal and higher-elevation areas.
Stronger wind gusts may create hazardous conditions along exposed
beaches and coastal areas, especially where loose or unsecured
objects are present. The combination of dry air, stronger winds,
and drying fuels will also increase fire danger.

Warm to locally hot conditions will continue, but limited low-
level moisture should keep Heat Risk limited through the period.
Little overall change is expected through much of Saturday, with
dry, stable, and breezy conditions prevailing. Moisture will begin
increasing late Saturday night as the leading edge of deeper
tropical moisture associated with Invest 92L approaches from the
east.


&&

.Long Term(Sunday through Thursday)...
Issued at 212 AM AST Thu Aug 13 2026

A wetter and more unstable weather pattern is expected Sunday into
Monday as Invest 92L (AL92) and its associated tropical moisture
approach the northeastern Caribbean. The latest model guidance
generally suggests AL92 will approach the region as an open
tropical wave, with most solutions tracking the wave axis south of
the islands while its most active portion moves across the
forecast area. This scenario would result in a significant
increase in tropical moisture, with precipitable water values
rising above 2 inches and potentially exceeding 2.4 inches at
times. Therefore, increasing showers and thunderstorms are
expected across Puerto Rico and the U.S. Virgin Islands, along
with an increased potential for lightning and flooding impacts.
The expected rainfall could also provide beneficial drought
relief, particularly across southern and eastern Puerto Rico and
the U.S. Virgin Islands.

Nevertheless, considerable uncertainty remains regarding the
system`s track, intensity, timing, and associated moisture
distribution as it approaches the northeastern Caribbean. Small
changes in the evolution or track of AL92 could significantly
influence the magnitude and location of rainfall and associated
impacts across the local islands. Therefore, continue to monitor
the latest forecasts and updates.

Behind the tropical wave, moisture levels are expected to
gradually decrease Tuesday through Thursday, with precipitable
water values returning to near-normal levels. Therefore, shower
and thunderstorm activity should become less widespread, although
passing trade-wind showers and locally induced afternoon
convection will remain possible each day. As conditions become
more favorable for greater heat stress, Heat Risk may increase
once again after Tuesday, particularly across coastal and urban
areas of Puerto Rico and the U.S. Virgin Islands.


&&

.AVIATION...
(06Z TAFS)
Issued at 212 AM AST Thu Aug 13 2026

Mainly VFR conds expected through the period. HZ associated with
Saharan dust may reduce VIS to around 6SM at times, gradually
improving through tonight. No significant SHRA/TSRA expected. E
winds increasing after 13Z at 15-20 kt with sea-breeze gusts 20-25
kt. E winds 20-25 kt aloft through FL150-FL200.


&&

.MARINE...
Issued at 212 AM AST Thu Aug 13 2026

As high pressure builds over the central Atlantic, a tightening
pressure gradient will support moderate to fresh easterly winds,
locally strong at times. Seas will become choppy to hazardous
tonight, building to 7 to 8 feet offshore and up to 7 feet
nearshore by Friday. Small Craft Advisories are in effect tonight
through at least Sunday for the offshore waters and passages, with
additional advisories possible for nearshore waters. Wetter and
more unstable conditions are expected Sunday into Monday as AL92
approaches, bringing increasing showers, gusty winds, and
thunderstorms.


&&

.BEACH FORECAST...
Issued at 212 AM AST Thu Aug 13 2026

A moderate risk of rip currents will continue today for nearly all
beaches of Puerto Rico, Vieques, Culebra, and the U.S. Virgin
Islands, except for protected western beaches.

Beginning Friday and continuing through the weekend, strengthening
trade winds and building seas will result in a high risk of life-
threatening rip currents for nearly all beaches, while protected
western beaches should remain at a moderate risk. Rip Current
Statements are in effect for the affected areas.

Beachgoers should exercise caution, swim near lifeguards, and heed
beach patrol flags and signs. Breezy to windy conditions may also
blow around unsecured beach equipment, including tents, chairs,
and umbrellas.


&&

.FIRE WEATHER...
Issued at 212 AM AST Thu Aug 13 2026

Fire weather concerns will increase today through Saturday as a
much drier air mass combines with strengthening easterly winds.
Recent rainfall may initially provide some mitigation, but
continued dry210ing of fine fuels is expected, particularly across
the southern and southwestern coastal plain of Puerto Rico.
Elevated fire danger is expected today, with concerns increasing
Friday and Saturday as dry and breezy to locally windy conditions
persist. Moisture will begin increasing late Saturday night,
eventually reducing fire weather concerns. Refer to the latest
Fire Danger Statement (RFDSJU) for additional details.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk from Friday morning through late Saturday
     night for PRZ001>003-005-007-008-011>013.

     Fire Danger Statement from 10 AM this morning through 4 PM AST
     this afternoon for PRZ014>019-022>027.

VI...High Rip Current Risk from Friday morning through late Saturday
     night for VIZ001-002.

     Fire Danger Statement from 10 AM this morning through 4 PM AST
     this afternoon for VIZ001-002-132000-.

AM...Small Craft Advisory from 6 PM this evening to 5 PM AST Sunday
     for AMZ711-723-733-741.

&&

$$

EVE...CVB/MRR
MID...ICP

NWS SJU Office Area Forecast Discussion