001
FXCA62 TJSJ 030932
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
532 AM AST Mon Nov 3 2025

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

.KEY MESSAGES...
Issued at 520 AM AST Mon Nov 3 2025

* As a trade wind perturbation continues to move across the area,
  breezy conditions will bring showers over windward areas today
  with afternoon convection forecast over interior to western
  Puerto Rico.

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

* Across the U.S. Virgin Islands, mainly fair weather will
  prevail, with passing showers moving in at times.

* A northerly swell forecast to arrive late in the workweek could
  further deteriorate the now moderate risk of rip currents.

&&

.Short Term (Today through Wednesday)...
Issued at 520 AM AST Mon Nov 3 2025

During the overnight period, a trade wind perturbation has been
moving across the region, increasing cloud cover and promoting
shower activity over the local waters as well as the windward and
coastal areas of Puerto Rico and USVI at times. Based on Doppler
radar estimates, rainfall amounts between 0.25 and 0.50 inches were
observed from northern to southeastern Puerto Rico, with some
isolated spots receiving close to 1 inch. Minimum temperatures
ranged in the 70s across coastal and lower elevation areas, and in
the 60s across higher elevations. Winds were from the east to
northeast at around 8 to 13 mph.

Today, as the trade wind perturbation continues to move across the
area, breezy conditions will bring additional quick-moving showers
over windward areas, increasing precipitable water values. According
to the latest guidance, PWAT values are expected to range between
1.90 and 2.20 inches, above normal for this time of year. By the
afternoon, the combination of available moisture, diurnal heating,
sea breeze convergence, and local effects will enhance shower and
isolated thunderstorm development across the interior and western
sectors. However, a mid-level ridge will act to limit convection. As
a result, significant rainfall accumulations are not expected,
though localized ponding or minor flooding cannot be ruled out,
consistent with the limited flood risk currently in place.

By Tuesday and Wednesday, variable weather conditions should
dominate. An upper-level low moving south of the region over the
Caribbean waters will slightly weaken the mid to upper level ridge
and atmospheric stability, cooling temperatures near 500 mb by
around 1 to 2 degrees Celsius. Precipitable water values are
forecast to range from near normal to slightly below normal (around
1.25 to 1.75 inches) as alternating patches of moisture and drier
air move across the area. On Tuesday, winds will shift from the east
to northeast, focusing afternoon convection with a few possible
thunderstorms over southwestern Puerto Rico. By Wednesday, winds
will veer back to the east, promoting convection over west-central
to western Puerto Rico. The flood risk will remain from limited to
slightly elevated tomorrow, Tuesday, across southwestern Puerto Rico
during the afternoon hours, while mainly limited on Wednesday.
Across the U.S. Virgin Islands, passing showers are expected today
as moisture increases, followed by generally fair weather for most
of the period.

&&

.Long Term (Thursday through Monday)...
Issued at 520 AM AST Mon Nov 3 2025

High pressure systems over the central Atlantic will promote
generally easterly steering flow while a mid level ridge is expected
to persist north of the region, promoting stability and drier
conditions aloft. Patches of both moisture and drier air will
continue to filter in and out of the local area throughout the rest
of the week under this easterly steering flow, becoming more
southeasterly on Saturday as the surface high moves westward.
Precipitable water (PWAT) values are forecast to fluctuate between
below normal to normal values during the rest of the week. Leaving
passing showers over windward sectors of PR/USVI during the morning
and overnight hours with afternoon showers and t-storms possible
over mainly western Puerto Rico, as diurnal heating, sea breeze
convergence, and orographic effects promote this convection and a
limited flooding risk. An upper low will also be present to our SW
to start the period, gradually moving NE as the workweek continues.
This upper low will somewhat increase instability and could induce
weak surface troughs. Up to a limited heat risk is likely to persist
during the rest of the week. Available moisture will be confined to
the lower levels throughout the start of next week, when deeper
moisture arrives in the form of a tropical wave. By late Saturday
and Sunday, a tropical wave is forecast to move over the islands,
increasing PWAT values to above 2 inches (above normal values) as
well as promote up to breezy southeasterly steering flow over
windward sectors. Latest Galvez-Davidson Index (GDI) values are up
to around +40 on Sunday, suggesting a potential for scattered t-
storms, heavy rain and an increased flooding risk. Lingering
moisture will persist on Monday under southeasterly steering flow.

&&

.AVIATION...
(06Z TAFS)
Issued at 520 AM AST Mon Nov 3 2025

Mainly VFR condition across most TAF sites this morning, however
brief periods of MVFR are possible across TJSJ due to period of -
SHRA with passing trade winds showers. VCSH across USVI TAF sites
SHRA/TSRA may develop across interior and W PR after 03/17Z,
possibly affecting the VCTY of TJBQ/TJPS. E to NE winds with periods
of gusty winds up to 20 to 25 kts across most sites after 03/13-14Z,
becoming lighter tonight.

&&

.MARINE...
Issued at 520 AM AST Mon Nov 3 2025

A surface high pressure over the central Atlantic will promote
moderate to locally fresh easterly trade winds until mainly this
evening as well as wind-driven, choppy seas. Small Craft Should
Exercise Caution over the Atlantic waters, the Mona & Anegada
Passages and the Offshore Caribbean Waters today. Decreasing winds
and subsiding seas are forecast by later tonight and until at least
Thursday. By Thursday and Friday a northerly swell will
deteriorate marine conditions, Small Craft Should Exercise Caution
during these days over exposed Atlantic waters.

&&

.BEACH FORECAST...
Issued at 520 AM AST Mon Nov 3 2025

There is a moderate risk of rip currents today for the northern,
eastern, southeastern, and some southern beaches of Puerto Rico. A
moderate risk of rip currents will also persist today for St.
Thomas, St. John, St. Croix, Culebra and Vieques.

Coverage of this moderate risk of rip currents will decrease
tonight and throughout mid-week, but will persist mainly over
northern exposed beaches of Puerto Rico and Culebra. St. Croix`s
moderate risk of rip currents will continue until late tonight.

By Thursday and Friday a northerly swell will deteriorate coastal
conditions, once again increasing the coverage of the moderate
risk of rip currents to most of the above mentioned areas with
some northern exposed beaches possibly reaching a high risk of rip
currents on Friday. For additional updates, visit
weather.gov/beach.

&&

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

$$

YZR/MRR