749
FXCA62 TJSJ 120843
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
443 AM AST Wed Nov 12 2025


.KEY MESSAGES...
Issued at 439 AM AST Wed Nov 12 2025

 * Variable conditions are expected to prevail from today through
   Friday, with mostly stable weather and passing showers in the
   afternoon for Puerto Rico and the U.S. Virgin Islands.
 * From Saturday into Sunday, an increase in showers and fresher
   temperatures is forecast as a frontal boundary approaches.

 * Hazardous marine and coastal conditions with seas up to 7 feet
   across the offshore Atlantic waters and a high risk of rip
   currents along the north exposed beaches of Puerto Rico,
   Culebra, and St. Croix from this evening throught Thursday.

 * For the U.S. Virgin Islands, isolated passing showers are
   forecast for the day, with a similar weather pattern for
   tomorrow.

&&

.Short Term(Today through Friday)...
Issued at 439 AM AST Wed Nov 12 2025

The most recent satellite imagery show an area of enhanced moisture
covering the northeast Caribbean, with precipitable water values
around 1.5 inches. This brought a few showers during the overnight
hours across eastern Puerto Rico and the northern Virgin Islands.
Rainfall accumulations was minimal. Skies were mostly clear to
partly cloudy, and temperatures dropped into the mid and upper 70s
in coastal areas, and the 60s in the mountain.

Local conditions will be dominated by a ridge in the mid and upper
levels, that is maintaining moisture trapped closer to the surface.
East of the Lesser Antilles, an upper level trough continues to
induce small patches of moisture that will be carried by the trade
winds irregularly. Even when the atmosphere is not prime for strong
shower production, some brief interruptions of rainfall is expected
at times along eastern Puerto Rico and in the Virgin Islands.
Rainfall in the afternoon should also be brief, with a very low risk
of flooding, mostly along western Puerto Rico.

By Friday, the ridge weakens in response to a long wave polar trough
exiting the eastern coast of the United States. This will cause the
trade winds to weaken, at speeds of 4 to 8 kts. While moisture will
remain limited, conditions could allow for stronger convection to
form in the afternoon along the interior of Puerto Rico.
Nevertheless, the risk of flooding should remain limited.

&&

.Long Term(Saturday through Wednesday)...
Issued at 439 AM AST Wed Nov 12 2025

The islands will be dominated mainly by a pre-frontal trough at
the surface and a trough at the mid-to-upper levels. At the
surface, the surface trough will weaken the pressure gradient,
resulting in variable and light winds from Saturday into Sunday
along the islands. According to the global model guidance, the
frontal boundary will dissipate just north of the region as a
surface high pressure builds just across the western Atlantic,
extending into the Central Atlantic. Although the frontal boundary
will remain to our north, enough deep enough moisture will reach
the islands. The available moisture trapped in the first 300 MB
[1000-700 MB] with precipitable water values from 1.5 to 1.7
inches, which are normal values for this time, will allow the
development of afternoon convection. Isolated thunderstorms are
expected, with the heaviest activity forecasted due to some
instability caused by the presence of the mid-level trough, which
enhances colder temperatures at 500 MB, ranging between -6 and -7
degrees Celsius. Since winds will be variable, the focus of the
showers and the translation movement can contribute to some
isolated urban flooding, with the heaviest showers occurring
during the afternoon hours.

From Monday onwards, as the surface high pressure migrates further
into the Central Atlantic, veering winds from the east-southeast
will again change the weather pattern across the islands.
Therefore, residents can expect a more typical weather pattern,
with an increase in heat indices in some coastal areas and
afternoon convection primarily across eastern sections of Puerto
Rico, specifically in the vicinity of El Yunque, extending to some
metropolitan areas and northwestern Puerto Rico. Rainfall
accumulation is not forecast to be significant; however, some
isolated urban and minor flooding cannot be ruled out in low-
lying areas.

&&

.AVIATION...
(06Z TAFS)
Issued at 439 AM AST Wed Nov 12 2025

Mainly VFR conditions expected to prevail through the forecast
period. SCT SHRA will persist across the Atlantic and Caribbean
waters, occasionally reaching the USVI and PR terminals. However,
impacts to operations are expected to be minimal to none. After 17Z,
SHRA are expected to develop in the Cordillera Central, which could
cause mountain obscuration, and very briefly reducing VIS and
ceilings in the vicinity of TJPS. Winds will be from the ENE at 12-
16 kts, with stronger gusts.
&&

.MARINE...
Issued at 439 AM AST Wed Nov 12 2025

A broad surface high pressure over the north-central Atlantic will
continue to promote moderate to locally fresh easterly winds across
the regional waters during the next few days, keeping choppy to
occasionally rough seas. Hazardous marine conditions are forecast due
to a north- northwesterly swell spreading across the local Atlantic
waters and passages from this evening through Thursday evening. As a
result, Small Craft Advisories will be in effect starting Wednesday
evening.

&&

.BEACH FORECAST...
Issued at 439 AM AST Wed Nov 12 2025

For today, a low risk of rip currents will persist along all
coastal areas of Puerto Rico, Culebra, Vieques, and the U.S.
Virgin Islands, increasing to moderate during nighttime hours. A
north-northwesterly swell is forecast to arrive across the
northern coastal areas from Thursday, enhancing breaking waves up
to 7 feet, resulting in a high risk of rip current. Beachgoers are
urged to stay tuned for further updates.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...Small Craft Advisory from 6 PM this evening to midnight AST
     Thursday night for AMZ711.

&&

$$

SHORT TERM & AVIATION...ERG
LONG TERM & MARINE....LIS