596
FXCA62 TJSJ 040923
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
523 AM AST Tue Nov 4 2025

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

.KEY MESSAGES...
Issued at 522 AM AST Tue Nov 4 2025

* Patches of both, humid and drier air, will continue to move over
  the area during the week, before a tropical wave aproaches the
  islands next Sunday.

* Variable conditions will persist today as a TUTT approaches and
  lingers near the region.

* At the U.S. Virgin Islands, mainly fair weather conditions will
  prevail, with occasional passing showers.

* By the end of the workweek, a northerly swell is forecast to
  arrive and deteriorate marine and coastal conditions.

&&

.Short Term (Today through Thursday)...
Issued at 522 AM AST Tue Nov 4 2025

Mostly quiet conditions prevailed overnight across Puerto Rico and
the U.S. Virgin Islands. Only a few passing showers moved across the
local waters, with some reaching the El Yunque area and the north-
central coast of Puerto Rico. However, based on Doppler radar
estimates, rainfall accumulations were minimal. Satellite imagery
indicated partly cloudy to mostly clear skies, with patchy fog
observed over the mountainous interior of Puerto Rico. Minimum
temperatures ranged from the 70s across coastal and lower-elevation
areas to the 60s across higher elevations. Winds were from the east
to northeast at around 5 to 10 mph.

Today, Tuesday, variable conditions will persist. Aloft, dynamics
will become slightly more favorable as a retrogressing TUTT begins
to move near the area, slightly weakening the mid-level ridging
pattern. At the same time, a patch of drier air at lower levels will
move in, reducing precipitable water values to near 1.25 inches
during the day, around the 25th percentile below normal. Winds will
turn more northeasterly today, leading to passing showers across
windward areas early, followed by afternoon convection developing
mainly across western and southwestern Puerto Rico. Shower coverage
is not expected to be significant and should remain mostly
localized. The limited flood risk highlights these areas, with
potential minor impacts including ponding on roadways, reduced
visibility, and slippery driving conditions.

Tonight into Wednesday, the TUTT will continue to linger near the
region, while its associated surface induced trough influences local
conditions, increasing moisture content. PWAT guidance suggests
values rising to around 1.75 to 2 inches, which will enhance the
frequency and coverage of showers across the U.S. Virgin Islands and
eastern Puerto Rico overnight, along with a limited flood threat.

On Wednesday, additional showers and a better chance of
thunderstorms are expected, supported by lower 500 mb temperatures.
This activity should be focused mainly across the interior and
western municipalities during the afternoon. By Thursday,
alternating patches of moisture and drier air will persist over the
area, resulting in weather conditions similar to Wednesday. Winds
shifting slightly to the east-southeast will bring slightly warmer
temperatures on Thursday, though the overall heat threat will remain
limited, primarily across coastal and urban areas each day of the
forecast period across all islands.

&&

.Long Term (Friday through Tuesday)...
Issued at 522 AM AST Tue Nov 4 2025

A surface high pressure system over the northern Atlantic will
gradually move eastward during the long term period as upper lows
move out of northeastern America. This high will generally be over
the central to eastern Atlantic by the end of the period. A weak mid
level ridge is also expected to persist north/northeast of the
region while upper level ridging will continue at or near the
region. Patches of both moisture and drier air will filter in and
out of the local area throughout the rest of the week under the
easterly to then southeasterly steering flow. Precipitable water
(PWAT) values are forecast to fluctuate between below normal to
normal values late in the week. This will promote a seasonal
pattern of passing showers over windward sectors of PR/USVI during
the morning and overnight hours with afternoon showers and
t-storms possible over mainly western/northwestern Puerto Rico, as
diurnal heating, sea breeze convergence, and orographic effects
promote this convection and a limited flooding risk. Up to a
limited heat risk is likely to persist during the rest of the
week. According to the latest guidance, available moisture will
mostly be confined to the lower levels throughout the period. The
latest model guidance has backed off on the intensity and PWAT
values of the, mentioned in previous discussions, tropical wave
over our area during the weekend. Southeasterly steering flow will
continue to steer moisture from the wave over our area but with
up to seasonal PWAT values while deeper moisture remains over the
offshore waters. This can still promote up to breezy southeasterly
steering flow over southern windward sectors. Patches of both
humid and drier air will to filter in and out of the local area
early next workweek under southeasterly steering flow, with
current model guidance suggesting a patch of drier air moving in
to end the period Tuesday afternoon and evening.

&&

.AVIATION...
(06Z TAFS)
Issued at 522 AM AST Tue Nov 4 2025

Prevailing VFR conditions across most TAF sites this forecast
period. VCSH possible across TJSJ and USVI TAF sites this morning.
SHRA/TSRA may develop across W PR after 04/17Z, possibly affecting
the VCTY of TJBQ/TJPS. After 04/23Z, VCSH or periods of -SHRA should
persist again across TJSJ and USVI sites. NE winds today at around
10 kts with some higher gusts up to 18 to 21 mph across TJPS and
TJBQ and typical sea breeze variations. Lighter to calm winds after
04/22Z across most sites.

&&

.MARINE...
Issued at 522 AM AST Tue Nov 4 2025

A weak surface high pressure over the central Atlantic will
promote light to moderate easterly winds for the next several
days. A surface low moving over the northwestern Atlantic will
generate a northerly swell that will build seas to around 6 feet
or higher across the Atlantic waters and passages late in the
week.

&&

.BEACH FORECAST...
Issued at 522 AM AST Tue Nov 4 2025

There is a moderate risk of rip currents today for the northern
and eastern beaches of Puerto Rico, as well as for northern
beaches of Culebra. There is a low risk of rip currents across
other coastlines of Puerto Rico, southern Culebra, Vieques, and
the U.S. Virgin Islands. By the end of the workweek, a northerly
swell will deteriorate coastal conditions, increasing the coverage
of the moderate risk of rip currents to the USVI, Vieques, and
north oriented beaches of western Puerto Rico. A high risk of rip
currents is possible on Friday for northern exposed beaches of
Puerto Rico, Culebra, St. Thomas and St. John. For additional
updates, visit weather.gov/beach.

&&

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

$$

YZR/MRR