057
FXCA62 TJSJ 151901
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
301 PM AST Sat Aug 15 2026

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

.KEY MESSAGES...
Issued at 244 PM AST Sat Aug 15 2026

- A tropical wave moving across the Caribbean Sea will gradually
  increase moisture from the rest of today into Sunday morning.
  Therefore, residents can expect an increase of fast-moving
  showers. Drier air will filter behind bringing low to moderate
  concentrations of Saharan dust.

- Breezy to windy conditions will continue through at least late
  Sunday, secure loose objects as they could blow around.

- A Heat Advisory is in effect through 5 PM AST for urban and
  coastal areas of Puerto Rico and the U.S. Virgin Islands.

- Hazardous marine and coastal conditions are ongoing and will
  continue through at least late Sunday. Small Craft Advisories
  and Rip Current Statement are in effect.

- A Red Flag Warning was issued for the coastal plains and hills
  of southern Puerto Rico and Vieques, while a Fire Danger
  Statement remains in effect for the rest of the areas.

&&

.Short Term(This evening through Monday)...
Issued at 244 PM AST Sat Aug 15 2026

The day will remain windy with mostly cloudy skies. Around 9 AM AST,
satellite imagery showed cloudiness associated with the outer bands
of the tropical wave moving south of the area, reaching the islands.
According to unofficial weather stations across the islands, wind
gusts of up to 41 mph were reported in Culebra and St. John, while
gusts generally ranged from 30 to 35 mph across the main islands.
Across Puerto Rico, sustained winds generally ranged from 20 to 26
mph. The Luis Munoz Marin International Airport station reported
a maximum wind gust of 35 mph, with sustained winds between 22 and
26 mph. As of 11 AM AST, Doppler radar indicated quick-moving
showers across northern and central Puerto Rico, affecting areas
from Bayamon westward toward Utuado. These showers were generally
brief due to the fast steering flow. Maximum daytime temperatures
were in the low 90s across northern and southern coastal areas
and in the 80s across the rest of the island. Maximum heat indices
ranged from 108 to 112 degrees across portions of north-central
Puerto Rico and the southern coastal areas.

For the rest of the day, variable weather conditions will prevail as
the tropical wave known as Invest 92L continues to move westward
across the Caribbean Sea. Moisture associated with the system will
continue to move across the islands; however, the bulk of the shower
and thunderstorm activity will remain south of the CWA. According to
high-resolution model guidance, an increase in rainfall activity is
forecast across eastern sections from late this evening into the
early Sunday morning hours. Rainfall accumulations are expected to
remain limited, generally between 1 and 1.5 inches, due to the fast-
moving nature of the showers. On Sunday, variable weather conditions
will continue; however, the bulk of the moisture is forecast to
quickly move out of the region by Sunday afternoon. Therefore, the
islands can expect passing showers over the local waters and eastern
sections during the morning, followed by afternoon showers across
western Puerto Rico. Thereafter, the influence of a surface high
pressure will maintain easterly winds across the islands through
Monday. Under this pattern, a drier air mass with lower precipitable
water values will move into the region, promoting a more stable
weather pattern. Hazy skies will also be possible on Monday as
Saharan dust particles remain across the area, as suggested by the
NASA Goddard Earth Observing System Model, Version 5 (GEOS-5).

The heat threat is expected to persist throughout the period across
urban and coastal areas due to warm temperatures and elevated heat
indices. These conditions could increase the risk of heat
exhaustion, particularly among vulnerable populations and
individuals working or participating in outdoor activities during
the peak heating hours of the day. Residents and visitors are
encouraged to stay hydrated, limit prolonged exposure to direct
sunlight, and take frequent breaks in shaded or air-conditioned
areas.

&&

.Long Term(Tuesday through Saturday)...
Issued at 249 AM AST Sat Aug 15 2026

A relatively dry and stable weather pattern is expected Tuesday,
followed by increasing moisture and instability Wednesday into
Thursday as Invest 94L (AL94) approaches the northeastern Caribbean.
On Tuesday, PWAT values should remain around 1.3 to 1.5 inches, with
relatively dry mid-levels limiting shower and thunderstorm coverage.
Moisture will gradually increase Wednesday, with the most
significant surge expected Wednesday night into Thursday, when PWAT
could rise to around 2 inches or greater. Increasing low- to mid-
level moisture, cooler 500 mb temperatures, and steeper mid-level
lapse rates should favor increasing showers and thunderstorms, with
locally heavy rainfall and urban and small-stream flooding possible.

Considerable uncertainty remains Thursday into Saturday regarding
the evolution, track, timing, and moisture distribution associated
with AL94. Regardless of development, the disturbance could bring a
substantial tropical moisture envelope across or near the local
islands. Small changes in its track or evolution could significantly
influence rainfall coverage and amounts. Although moisture may
fluctuate Friday into Saturday, cooler temperatures aloft and
favorable mid-level lapse rates should maintain an unstable
environment, supporting periods of showers and thunderstorms where
deeper moisture persists. Therefore, the flooding threat will depend
largely on the duration and location of the deepest moisture.

The expected rainfall could provide beneficial moisture to areas
experiencing dry conditions; however, significant drought relief is
not anticipated, as rainfall amounts and coverage will likely vary
considerably. Heat will also remain a concern, particularly Tuesday
and during periods of sufficient sunshine later in the week.
Increasing humidity may maintain elevated heat indices, while
greater cloud and shower coverage Thursday onward could provide some
relief. Continue to monitor the latest forecasts and updates
regarding the evolution of AL94..LONG TERM...

&&

.AVIATION...
(18Z TAFS)
Issued at 244 PM AST Sat Aug 15 2026

Breezy to windy conditions will prevail, with easterly winds between
20 and 28 knots and gusts up to 35 knots. Quick-moving SHRA are
possible across the area as Invest 92L moves westward across the
Caribbean Sea. Windy conditions will persist at the TAF sites
overnight. SHRA with VCTS are expected at TJPS and TIST after 16/03Z
as TSRA associated with the tropical wave moves near the
terminals.

&&

.MARINE...
Issued at 244 PM AST Sat Aug 15 2026

A tight pressure gradient will maintain fresh to locally strong
easterly winds and choppy to rough seas of 5 to 7 feet, with
occasional seas reaching 8 to 9 feet across the offshore waters
and local passages. Small Craft Advisories remain in effect
through at least late Sunday night due to this hazardous
conditions. Showers and thunderstorms are expected to become more
frequent from this afternoon into Sunday morning as the tropical
wave moves south of the region, bringing increased shower and
thunderstorm activity, particularly across the Caribbean waters
and local passages.

&&

.BEACH FORECAST...
Issued at 244 PM AST Sat Aug 15 2026

Tonight and Sunday, there is a high risk of rip currents across
most beaches of Puerto Rico, Vieques, Culebra, and the U.S. Virgin
Islands due to breezy to windy conditions producing breaking
waves 6 to 7 feet. The Rip Current Statement remains in effect
through at least late Sunday night. Beachgoers are urged to stay
out of the water and heed the advice of lifeguards, beach patrol
flags, and posted signs.

By Monday, the risk is forecast to return to moderate levels
across most beaches, but life-threatening rip currents will remain
possible. Tuesday into midweek, winds are expected to subside,
further decreasing the risk. However, remember that even when the
risk is low, life-threatening rip currents can occur near groins,
jetties, reefs, and piers.


&&

.FIRE WEATHER...
Issued at 244 PM AST Sat Aug 15 2026

Elevated fire danger continues today as minimum relative humidities
remain around mid 40s to low 50s, particularly across the coastal
plains and hills of southern Puerto Rico and Vieques. That combined
with breezy to windy conditions are elevating the risk of fire
spread. A Fire Danger Statement remains in effect across portions
of Puerto Rico, Culebra, and the U.S. Virgin Islands until 5 PM
AST this afternoon, while a Red Flag Warning was issued for the coastal
plains and hills of southern Puerto Rico and Vieques.

The northern periphery of an approaching tropical wave should
continue to approach, slightly increasing the moisture content
across the area. Nonetheless, the dry conditions will persist
until then.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Heat Advisory until 5 PM AST this afternoon for PRZ001>005-007-
     008-010>013.

     High Rip Current Risk through late Sunday night for PRZ001>003-
     005-007-008-011>013.

     Red Flag Warning until 5 PM AST this afternoon for PRZ014-015-
     025-027.

VI...Heat Advisory until 5 PM AST this afternoon for VIZ001-002.

     High Rip Current Risk through late Sunday night for VIZ001-002.

AM...Small Craft Advisory until midnight AST Sunday night for AMZ711-
     723-733-741.

     Small Craft Advisory until noon AST Sunday for AMZ712-716-726-
     735.

&&

$$

SHORT TERM/AVIATION...LIS
LONG TERM...CVB
MARINE/BEACH/FIRE...YZR