418
FXCA62 TJSJ 150825
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
425 AM AST Sat Nov 15 2025

.KEY MESSAGES...
Issued at 402 AM AST Sat Nov 15 2025

* A pre-frontal trough will enhance light winds and moisture
   across the islands, increasing the potential for afternoon
   showers.

 * An increase in showers and thunderstorms is expected tomorrow,
   particularly across the interior and northern parts of Puerto
   Rico, including the San Juan metropolitan area.

 * For the U.S. Virgin Islands, a variable weather pattern will persist
   today and tomorrow with periods of brief passing showers.

 * There is a moderate risk of rip currents for the north-facing
   coastal areas of the islands.

&&

.Short Term(Today through Monday)...
Issued at 402 AM AST Sat Nov 15 2025

Overnight, mainly calm weather conditions prevailed across Puerto
Rico and the U.S. Virgin Islands. A few showers developed over the
waters but accumulations remained low. Minimum temperatures stayed
in the low 80s across urban and coastal areas, while the higher
terrain cooled into the upper 60s to mid-70s. Winds were generally
from the east, becoming variable at times, with speeds around 5 to
10 mph.

For the weekend, the latest model guidance indicates relative
humidity and precipitable water values near normal, along with a
weakening mid to upper level trough east of the area as a deep polar
trough over the western Atlantic shifts into the central Atlantic.
By today (Saturday), winds will become lighter or even variable,
allowing afternoon convection to develop and spread over a broader
portion of the islands. These weak steering winds will cause showers
and thunderstorms to move slowly, increasing their potential to
regenerate and produce widespread rainfall. As the deep-layer trough
moves closer to the region from Saturday into Sunday with its
greatest influence expected from Saturday evening through Sunday
evening it will cool the mid-levels to below-normal values,
enhancing instability and allowing deeper moisture to build through
the column. As a result, elevated flooding risk remains possible,
particularly for Puerto Rico from this afternoon onwards. By the end
of the weekend, a high-pressure system will position itself north of
the area, allowing winds to become more east-southeasterly.

On Monday, a low-pressure system will approach the region from the
southeast, allowing precipitable water values to remain near the
50th percentile, or near-normal levels for this time of year. We
encourage residents and visitors to continue monitoring the forecast
for potential impacts in their area.


&&

.Long Term(Tuesday through Saturday)...
Issued at 402 AM AST Sat Nov 15 2025

During early Tuesday into early Wednesday, the islands will be
mainly influenced by a surface high pressure over the central
Atlantic, resulting in mostly east-southeasterly winds. Embedded
within this wind flow are patches of trapped tropical moisture
with precipitable water values between 1.4 and 1.6 inches.
Although this moisture will be present and concentrated near 850
MB, drier conditions are expected from 500 to 250 MB due to a
stable weather pattern. Global models suggest this setup will
bring some showers across the U.S. Virgin Islands and eastern
Puerto Rico at times, followed by afternoon convection over
western Puerto Rico. Since the available moisture is expected to
remain shallow, rainfall should be only locally heavy, with a low
probability of urban or small-stream flooding.

A more stable and drier weather pattern is forecast from late
Thursday into Friday. A broad and strengthening surface high
pressure system exiting the eastern coast of the United States and
extending into the central Atlantic will establish a
northeasterly wind flow across the region. This shift in the wind
pattern will transport a drier and cooler air mass over the
islands, limiting shower development and improving overall weather
conditions. This shift will also support a cold-advection pattern
mainly across the local northern waters. According to the 925 MB
temperature fields, temperatures are expected to decrease across
the islands.

&&

.AVIATION...
(06Z TAFS)
Issued at 402 AM AST Sat Nov 15 2025

Mainly VFR conditions prevailing across TAF sites during the
morning hours. After 15/16-17Z, intermittent periods of MVFR conds
are possible due to VCTS or TSRA across TJSJ, TJPS, and TJBQ
resulting in lower ceilings, brief higher winds, and reduced
visibilities. After 15/23Z, VFR conditions are expected to
prevail, but periods of VCSH cannot be ruled out at most TAF
sites. Expect variable winds mainly below 8 knots, becoming even
more calm tonight. &&

.MARINE...
Issued at 402 AM AST Sat Nov 15 2025

A frontal boundary and the associated pre-frontal trough located
north of the islands will continue to result in a light to gentle
easterly wind flow across the local islands. For today, surface
winds are expected to become more from the east-southeast later
today into Sunday as a weak surface high establishes north of the
region. Therefore, mariners can expect surface winds up to 10
knots with seas up to 5 feet and up to 4 feet along the coastal
waters in the Atlantic, and even lower across the Caribbean Sea.

&&

.BEACH FORECAST...
Issued at 402 AM AST Sat Nov 15 2025

There is a moderate risk of rip currents across the northern, exposed
local beaches, and a low risk of rip currents across the southern
coastal areas. Although conditions are suitable for beachgoers,
visitors, and residents are urged to be aware of other coastal
hazards, including afternoon lightning in the western sections of
Puerto Rico.

&&

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

$$

SHORT TERM...MMC
LONG TERM & MARINE....LIS
AVIATION...YZR