Your Number One Source for Real-Time Puerto Rico Weather & Hurricane Tracking Updates

995
FXCA62 TJSJ 060857
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
457 AM AST Sat Dec 6 2025

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

.KEY MESSAGES...
Issued at 453 AM AST Sat Dec 6 2025

* Mostly fair and stable weather will continue for Puerto Rico, with
  a few quick showers at times, especially overnight and in the
  morning across eastern areas.

* The U.S. Virgin Islands will also see fair weather, with
  occasional brief showers mainly during the night and early morning
  hours.

* Winds will gradually increase by the end of the workweek, leading
  to breezier conditions over the islands and coastal waters.

* A northerly swell expected late in the week, combined with
  increasing winds, may lead to rougher seas and a higher risk of
  life-threatening rip currents, though some uncertainty remains
  regarding its timing and strength.

&&

.Short Term(Today through Monday)...
Issued at 453 AM AST Sat Dec 6 2025

Weather conditions during the night remained variable with passing
showers due to moisture and cloudiness that moved across the local
islands. The shower activity was limited to northern coastal areas,
affecting only those areas with minimal rainfall accumulations.
Overnight temperatures were in the low to mid 70s across coastal and
urban areas, and even colder in the interior and mountain areas.

The short-term forecast remains on track. At the mid to upper
levels, a broad surface high-pressure system will continue to result
in mostly drier air aloft, stable conditions, and warmer
temperatures at 500 MB. Under this stable weather pattern, some
pockets of trapped moisture at 850 MB will move in and out due to
the moderate easterly winds across the area. According to the
precipitable water values from the derived satellite imagery, values
fluctuate between 1.15 and 1.4 inches today and are even drier with
a PWAT of around 1 inch for the rest of the period. Additionally,
the surface high pressure across the central Atlantic will hold for
today, with a slight increase in the pressure gradient resulting in
breezy conditions.

Given the expected conditions, a mostly stable weather pattern is
forecast for today with breezy conditions and limited showers. Since
the weather pattern will stay very stable, a lightning threat is not
expected today. On Sunday, the presence of the mid to upper-level
high pressure will hold stable conditions; however, the high-
resolution model suggests an increase in passing showers from late
Saturday into Sunday, increasing the Probability of Precipitation
(POP) up to 50 percent across eastern Puerto Rico and the U.S.
Virgin Islands. As the surface high pressure moves farther east,
veering winds are forecast on Tuesday, pushing tiny patches of
moisture along the east side of the CWA as suggested by the global
model guidance from the GFS and ECMWF. Additionally, this wind
surface pattern might result in slightly warmer coastal and urban
daytime temperatures.

&&

.Long Term(Tuesday through Saturday)...
Issued at 453 AM AST Sat Dec 6 2025

A persistent mid-level ridge will dominate the period, maintaining
below- to near-normal mid-level relative humidity and generally
stable conditions. Climatology comparisons keep 700-500 mb relative
humidity in the lower to mid percentiles, but periodic patches of
low-level moisture will still move through, producing brief PWAT
increases and allowing isolated to scattered showers mainly across
eastern PR and the USVI during the nighttime and morning hours.
Afternoon showers over western Puerto Rico remain possible whenever
moisture deepens toward 700 mb. Even with the ridging aloft, 500 mb
temperatures are expected to remain cool enough for seasonal 700-500
mb lapse rates to support limited afternoon convection. Any storms
that develop will be short-lived and shallow, but a few brief
thunderstorms cannot be ruled out.

At the surface, southeast winds start out light early in the period
due to a weak pressure gradient. By the end of the workweek, winds
will strengthen and shift slightly east-southeast as the gradient
tightens across the northeastern Caribbean. Temperatures will remain
above normal, particularly early in the period under a southeasterly
wind flow, supported by 925 mb temperatures and 1000-850 mb
thickness values running near to above normal. Highs will generally
reach the mid to upper 80s at lower elevations.

Overall, the pattern favors stable conditions with passing shallow
moisture, occasional brief convection, increasing winds late in the
workweek, and continued warm temperatures.

&&

.AVIATION...
(06Z TAFS)
Issued at 453 AM AST Sat Dec 6 2025

VFR conditions will persist across all TAF sites during the period.
Winds will remain from the east, peaking up up to 15 knots from
06/15Z. VCSH to -RA still expected across TJSJ and TIST for the
following hours. Some brief passing showers are expected in isolated
areas across the mountains, resulting in lower ceilings and reduced
VIS. An increase in -SHRA is forecast from 07/06Z across TIST, TISX,
and TJSJ.

&&

.MARINE...
Issued at 453 AM AST Sat Dec 6 2025

An east to northeast 4 to 5 ft swell at around 10 seconds and
moderate trades will promote choppy seas across most offshore
waters and local passages today. A building surface high pressure
north of the area will maintain moderate to locally fresh trades
(easterlies) on Sunday before subsiding early next week.

&&

.BEACH FORECAST...
Issued at 453 AM AST Sat Dec 6 2025

Low to moderate rip current risk is expected through early next
week. Model guidance also suggests a long-period northerly swell
arriving in the Atlantic waters late in the workweek, which will
result in a potential increase in the rip current risk.
Strengthening winds may contribute as well. Some discrepancies
remain among model solutions regarding the timing and magnitude of
the swell, adding uncertainty to the forecast. Continued monitoring
is advised as conditions evolve.

For localized and updated risk levels, visit weather.gov/beach/sju.

&&

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

$$

SHORT TERM & AVIATION...LIS
LONG TERM, MARINE & BEACH FORECAST....CVB

NWS SJU Office Area Forecast Discussion