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076
FXCA62 TJSJ 101857
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
257 PM AST Sun May 10 2026

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

.KEY MESSAGES...
Updated at 257 PM AST Sun May 10 2026

* Breezy conditions and a limited heat threat will persist across
  many coastal and urban areas of the islands.

* Periods of passing showers will continue to affect windward
  sections of the islands, followed by locally induced afternoon
  showers over western Puerto Rico each day.

* Across the U.S. Virgin Islands, breezy conditions and occasional
  trade wind showers are expected. Highs reaching the upper 80s
  to lower 90s across urban and coastal locations.

* A moderate risk of rip currents will continue along the north
  and east-facing beaches of Puerto Rico, Culebra, and the U.S.
  Virgin Islands.

&&

.Short Term(This evening through Tuesday)...
Issued at 257 PM AST Sun May 10 2026

Mostly tranquil conditions have persisted this Sunday, with the
exception of a few passing showers across the U.S. Virgin Islands
and portions of Puerto Rico. Breezy to windy conditions have been
observed, with peak gusts ranging from 25 to 35 mph, as recorded
at several official airport stations. Daytime highs have generally
ranged from the mid to upper 80s, with isolated locations
reaching the low 90s in urban and coastal areas of Puerto Rico and
the USVI, and the low 80s across higher elevations.

The forecast remains generally on track. The dominant feature
through early this upcoming week will continue to be mid-level
ridging and a generally dry air mass over the region.
Strengthening surface high pressure over the central Atlantic will
promote moderate to fresh easterly to east-southeasterly winds
around 15 to 20 knots, with higher gusts near coastal areas.
Current satellite-derived precipitable water (PWAT) values range
between 1.30 and 1.45 inches, below the seasonal average. For the
rest of the afternoon, isolated to scattered trade wind showers
will continue to move at times with occasional patches of moisture
and locally induced activity. No significant flooding is
expected.

From Monday afternoon through Tuesday, a slight increase in
moisture is anticipated, with PWATs rising toward 1.75 inches,
approaching the climatological average values. However, this
moisture will remain mostly confined to lower levels. The mid-to-
upper levels will stay exceptionally dry, with 700 to 500 mb
relative humidity frequently dropping below 40%, and overall
forecasted lapse rates remain unfavorable for deep convection.
Consequently, significant thunderstorm development is unlikely.
Any rainfall is expected from brief patches of slightly higher
low-level moisture moving across the U.S. Virgin Islands and
eastern Puerto Rico during overnight and early morning hours. By
the afternoon, daytime heating and local effects may trigger
scattered, localized showers over the interior and western
municipalities of Puerto Rico. Overall rainfall accumulations are
expected to be light, as showers should move quickly.

The primary hazard continues to be heat. Current 925 mb temperature
guidance indicates a steady diurnal warming trend throughout the
period. This persistent warm air mass, combined with available
surface moisture, will result in daytime highs in the upper 80s to
lower 90s across lower elevations, urban areas, and coastal plains.
Heat indices may exceed 100 degrees F during peak afternoon hours.
Residents and visitors are strongly encouraged to stay hydrated
and limit sun exposure during the hottest part of the day.

&&

.Long Term(Wednesday through Sunday)...
Issued at 310 AM AST Sun May 10 2026

A drier to seasonal weather pattern is anticipated over the long-
term forecast. A broad surface high pressure is expected to linger
over the Central Atlantic, promoting E-SE winds through most of the
period. Additionally, a mid-level ridge will linger through most of
the period, maintaining warmer than normal temperatures (500 mb
temperatures fluctuating between -4 and -5 degrees Celsius),
promoting subsidence and stability aloft. From Wednesday through
Friday, patches of moisture will move from time to time, as the
latest model guidance suggests an increase in moisture content (PWAT
values between 1.5 and 1.75 inches). Passing showers are likely
overnight into the morning hours over windward sections of the
islands, with shallow afternoon convection in the western/northwestern
section of Puerto Rico. Although shower activity may not lead to
significant flooding impacts, localized areas can expect puddles
over the roads and may become hazardous for drivers. By Saturday
and Sunday, another surface high pressure moving over the Western
Atlantic, and the high over the Central Atlantic may induce a col
region north of the region, weakening the pressure gradient and
winds. Due to local effects, combined with diurnal heating and sea
breeze convergence, afternoon showers, particularly over interior
and western Puerto Rico, may become stationary, increasing
flooding potential. Ponding of water over roadways and poorly
drained areas can be expected given these conditions, along with
minor flooding. Isolated thunderstorms, on the other hand, cannot
be ruled out.

Under an east-southeasterly wind pattern, warmer-than-normal
temperatures are expected during the long-term forecast. Combined
with the available moisture content, heat indexes will likely
surpass 100 degrees and even meet Heat Advisory Criteria. Residents
and visitors are encouraged to stay tuned for further updates, as
these warm to hot conditions can affect most individuals sensitive
to heat.

Based on the latest NASA DUex product, minor concentrations of SAL
may reach the CWA on Wednesday, but may affect people sensitive to
these particles.

&&

.AVIATION...
(18Z TAFS)
Issued at 257 PM AST Sun May 10 2026

Mainly VFR conditions are expected to prevail. Quick moving -
SHRA/VCSH steered by breezy E to ESE winds will continue to affect
most terminals through 10/23z and eastern and southern terminals
thereafter. This can promote brief MVFR conditions. E to ESE winds
will continue at 16-22 kts, with higher gusts up to 24 to 30 kts,
winds will decrease, becoming lighter and variable after 11/00Z,
picking up again after 11/13z with sea breeze variations.

&&

.MARINE...
Issued at 257 PM AST Sun May 10 2026

A surface high pressure over the central Atlantic will promote
moderate to locally fresh east to southeast winds across the
regional waters through at least midweek, decreasing somewhat after.
Seas will range between 3 and 5 feet, with occasional seas up to 6
feet. A small long-period northeasterly swell is also expected to
arrive by midweek and spread across local waters. Choppy seas will
continue as sustained winds of 15 to 20 knots, with occasionally
higher gusts persist. Small craft are urged to exercise caution
across most local waters.

&&

.BEACH FORECAST...
Issued at 257 PM AST Sun May 10 2026

Up to a moderate risk of rip currents (life-threatening rip
currents are possible in the surf zone) is forecast to continue
tonight and tomorrow along the north, east, and southeast-facing
beaches of Puerto Rico, Culebra, Vieques and St. Croix. A low risk
of rip currents will continue elsewhere. However, even if the
risk for rip currents is low, life-threatening rip currents often
occur in the vicinity of groins, jetties, reefs, and piers. A
similar pattern will continue into next week as breezy conditions
persist. A small long-period northeasterly swell is expected to
arrive by mid-week and spread across local waters, resulting in in
breaking waves of up to 4 to 5 feet, occasionally higher at
times. For additional information, visit: weather.gov/beach/sju.

If you become caught in a rip current, yell for help. Remain calm,
do not exhaust yourself and stay afloat while waiting for help. If
you have to swim out of a rip current, swim parallel to shore and
back toward the beach when possible. Do not attempt to swim directly
against a rip current as you will tire quickly.

&&

.FIRE WEATHER...
Issued at 257 PM AST Sun May 10 2026

An elevated fire threat continues through this afternoon,
particularly across the southern coastal plains of Puerto Rico, as
a result, the Fire Danger Statement remains in effect. Rainfall
has been very limited along the southern sections, and a dry air
mass over the region has allowed relative humidity to drop to
critical fire weather levels. RAWS stations have recorded relative
humidity in the upper 40s to low 50s, along with sustained winds
of 15 to 20 mph and gusts up to 30 mph. Additionally, KBDI values
remain elevated, especially in Cabo Rojo. These conditions favor
the rapid spread of wildfires across the southern coastal plains.

Fire management partners are urged to remain vigilant, as similar
conditions are expected to persist in the coming days. The
issuance of additional Fire Danger Statements (RFDSJU) cannot be
ruled out.

&&

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

$$

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

NWS SJU Office Area Forecast Discussion