323
FXCA62 TJSJ 111901
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
301 PM AST Thu Dec 11 2025

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

.KEY MESSAGES...
Issued at 259 PM AST Thu Dec 11 2025

* Choppy to rough seas and life-threatening rip currents are
  expected to continue through the weekend.

* Breezy to locally windy conditions are expected across the
  islands, particularly from Friday through Sunday.

* For Puerto Rico, passing showers are expected mainly during the
  night/early morning hours across the eastern sections, followed by
  limited afternoon shower activity over the northwest.

* For the U.S. Virgin Islands, expect isolated showers tonight into
  Friday morning.

&&

.Short Term(This evening through Saturday)...
Issued at 259 PM AST Thu Dec 11 2025

Generally fair weather under breezy to locally windy southeasterly
flow prevailed over the islands. These brought shower activity
towards windward sectors; current radar imagery detects shower
activity moving over east-southeast PR, with additional showers at
or in the vicinity of the USVI, Vieques and Culebra. Coastal
highs reached the mid to upper 80s, with localized stations
reaching the low 90s. Meanwhile, highs across higher elevations of
Puerto Rico remained in the 70s. Several coastal official and
unofficial stations report sustained winds between around 13-20
mph with higher gusts. Luis Munoz Marin, Cyril E. King and Henry
E. Rohlsen Int. Airports have reported winds/gusts of 20g25, 20g28
and 20g27 mph, respectively.

A surface high pressure over the central to eastern Atlantic will
continue to promote a southeasterly steering flow during the period.
This steering flow will continue to drag patches of moisture and
drier air towards the region. Current Satellite Derived Precipitable
Water (PWAT) values indicate a patch of more humid air (PWAT values
up to around 1.75 in) over the east to southeastern region related
to a disturbance. Current model guidance indicates that this patch
will continue to move over the islands tonight before a patch of
drier air (PWAT values around 0.95 in) reaches the area tomorrow
morning. Patches of more humid air will become more frequent
tomorrow morning onwards, with the most notable one (PWAT values
near 2 in), another disturbance, arriving by late Saturday morning
and into the long term period. These patches of moisture will
promote an increase in shower activity over windward sectors, while
afternoon showers over northeastern PR remains possible each
afternoon. A mid level ridge northeast of the region will serve to
limit shower development, however isolated areas can experience
ponding of water over roadways and poorly drained areas. This
southeasterly flow will result in normal to above normal 925 mb
temperatures and up to breezy to locally windy conditions (15 to 25
mph with higher gusts up to 35 mph), especially on Saturday.&&

.Long Term(Sunday through next Wednesday)...
Issued at 442 AM AST Thu Dec 11 2025

A broad surface high pressure will linger near and south of the
Azores through the long term period. Meanwhile, a cold front is
expected to move early in the workweek over the western Atlantic.
This surface pattern will promote southeasterly winds over the
local area, leading to warmer than normal daytime temperatures
across the islands. Max temps are forecast to range from the upper
80s to low 90s in some of the lower elevations, with heat indices
reaching the low 100s, particularly in western PR.

In terms of weather conditions, a similar weather pattern is
expected early in the period due to the influence of a mid-to
upper-level ridge to the east/northeast of the region. This will
promote fairly stable conditions, with brief patches of moisture
embedded in the trades bringing passing showers across the USVI
and eastern portions of PR during the night. Shallow afternoon
convection is still expected to develop over NW PR, but rainfall
accumulations are not expected to cause flooding concerns.
However, by midweek, an upper level trough will bring SW winds
aloft, and cause a brief weakness at the surface that will allow
for better pooling of moisture over the area as weak surface
troughs move from east to west. This will increase the chance of
showers between 40-60% each day across the islands, with a slight
chance of thunderstorm development over west/northwest PR late in
the afternoon hours.

&&

.AVIATION...
(18Z TAFS)
Issued at 259 PM AST Thu Dec 11 2025

VFR conds are expected to prevail this forecast period. Overall E to
SE winds flow through 11/23Z around 10 to 12 kts and gust up to 22
kts. Overnight, lighter winds and VCSH brfly promoting MVFR conds
across USVI TAF sites and TJSJ. By 12/14Z, expect winds from the SE
btwn 12-15 kt with gusts up to 25 kts.

&&

.MARINE...
Issued at 259 PM AST Thu Dec 11 2025

A surface high pressure will continue to build near the Azores
through the weekend. A weak cold front and another surface high
pressure will move from the western Atlantic into the central
Atlantic during the next few days. This will promote moderate to
locally fresh east to southeast trades across the local waters.
Increasing winds and a long period northerly swell will cause choppy
to rough seas, mostly over the offshore Atlantic waters. A Small
Craft Advisory (SCA) is in effect for the offshore Atlantic waters
through at least 6 PM AST Friday. Conditions will be hazardous to
small craft. Inexperienced mariners, especially those operating
smaller vessels, should avoid navigating in hazardous conditions.
SCA conditions could spread towards sectors of the Anegada and
Caribbean waters later this weekend.

&&

.BEACH FORECAST...
Issued at 259 PM AST Thu Dec 11 2025

There is a High Risk of Rip Currents (life-threatening rip currents
are likely in the surf zone) through 6 AM Saturday the for the
northwestern to northeastern beaches of Puerto Rico, as well as for
Culebra and, starting at 6 PM AST this evening, St. Thomas and St.
John. Factors that are deteriorating coastal conditions include a
long period northerly swell and increasing wind waves. These will
promote life-threatening rip currents along the north and east
facing beaches of the islands during the next couple of days. Other
coastal areas will have up to a moderate risk of rip currents (life-
threatening rip currents are possible in the surf zone). For
additional information, visit weather.gov/beach.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Friday night for PRZ001-002-
     005-008-012.

VI...High Rip Current Risk from 6 PM AST this evening through late
     Friday night for VIZ001.

AM...Small Craft Advisory until 6 PM AST Friday for AMZ711.

&&

$$

MRR/YZR

NWS SJU Office Area Forecast Discussion