456
FXCA62 TJSJ 191506
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
1106 AM AST Wed Nov 19 2025

...New BEACH FORECAST...

.KEY MESSAGES...
Issued at 1106 AM AST Wed Nov 19 2025

* Life-threatening rip currents are expected along the north-
  facing beaches in Puerto Rico, Culebra, and the eastern half of
  St. Croix through Thursday afternoon.

* Afternoon convection will elevate flooding and lightning risk
  over portions of western and southwestern Puerto Rico.

* Passing showers and isolated thunderstorms will bring periods of
  heavy rainfall across the U.S. Virgin islands and eastern Puerto
  Rico during the morning hours.

* Drier air and cooler temperatures are anticipated by Thursday
  into the weekend.

&&

.Short Term(Today through Friday)...
Issued at 333 AM AST Wed Nov 19 2025

Light to moderate showers prevailed across the local waters during
the night and early morning hours, with some of those showers
briefly streaming across some coastal sectors. Radar estimated
rainfall since midnight reported minimal accumulations over northern
coastal sectors of Puerto Rico, southeastern to eastern interior PR
(up to 0.6 in), Vieques, and coastal sectors of the USVI (around
0.01 in). Minimum temperatures were in the low to mid 70s across
most lower elevations of Puerto Rico, with some coastal and urban
stations reporting lows in the upper 70s. Interior sectors of Puerto
Rico, where patchy fog was also detected, reported minimum
temperatures in the low 60s. Minimum temperatures were in the
upper 70s to low 80s at the USVI, Vieques and Culebra.

For today, another variable weather pattern is forecast across the
islands, mostly under an easterly wind flow. At the surface, there
is an increase in trapped moisture associated with a surface
disturbance just east of the region. According to moisture-derived
satellite imagery, precipitable water values will range between 2.0
and 2.2 inches, which are slightly above climatological normals.
This significant increase in cloudiness and moisture will support
another variable weather day, with cloudiness and passing showers
along eastern Puerto Rico during the morning hours, followed by
afternoon convection with thunderstorm activity. Veering winds
during the day will focus shower activity across the western
interior into the southwestern areas as they gradually become more
northeasterly. Widespread shower activity in other areas will depend
entirely on the influence of the mid-level ridge, which may inhibit
the development of stronger vertical showers.

Conditions will rapidly change from Thursday into Friday. At the
surface, high pressure across the western Atlantic, together with
the influence of an induced surface trough from an upper-level
trough just north of the islands, will result in northeasterly
winds. Under this evolving pattern, drier air will filter into the
islands. According to global model guidance, precipitable water
values will drop drastically to around 1.1 inches, resulting in
mostly clear skies with minimal shower activity each day. A
different pattern is expected across the mid to upper levels, as a
trough erodes the mid-level ridge and enhances instability with
colder temperatures in the -8 to -7 degree range. Therefore,
although not enough moisture will be present, some isolated showers
cannot be ruled out, especially across southwestern Puerto Rico and
across northeastern areas during the evening and morning hours.

&&

.Long Term(Saturday through Wednesday)...
Issued at 333 AM AST Wed Nov 19 2025

Confidence remains high for the upcoming weekend forecast, with
variability for the first part of the workweek. A surface high
pressure building over the western Atlantic will promote
northeasterly winds through most of the period. Saturday is
anticipated to be the driest day of the long- term, as a cold,
drier airmass filters into the region. From the latest model
solutions, Precipitable Water (PWAT) values should drop below
normal (1.0 - 1.2 inches), with some members suggesting values
below the 25th percentile (below 1.0 inch). In terms of
instability, with the presence of a mid-level ridge lingering
through the period, thunderstorm activity will likely remain
limited. Additionally, the Galvez- Davison Index (GDI) keeps
suggesting a potential for isolated shallow convection. As
mentioned in the previous discussion, patches of moisture are
still likely to arrive by early Monday, with PWAT values expected
to increase but remain below climatological normal (likely between
1.2 and 1.4 inches, with a low chance of reaching 1.6 inches).
The most likely scenario remains, with showers moving into
windward sections of the local islands each night into the
morning, with afternoon convection over the mountain ranges into
southwestern Puerto Rico. Under this weather pattern, rainfall
accumulations may not necessarily bring significant flood and
lightning potential.

As mentioned in previous discussions, the fall in temperatures is
expected to continue, with 925 mb temperatures remaining below
climatological normal, with Saturday being the coolest day of the
period. Once again, the heat threat will remain low for the rest of
the forecast period.

&&

.AVIATION...
(06Z TAFS)
Issued at 333 AM AST Wed Nov 19 2025

VFR conditions will remain across all TAF sites during the
period. Winds will remain from the E veering from the NE at around
19/18Z up to 15 knots with gusty winds near strong TSRA and coastal
areas. Some brief MVFR conditions are possible across TJBQ and TJPS
from 19/16Z to 19/22Z due to SHRA and TSRA lowering cigs and with a
reduction in VIS. VCSH are expected along most of the eastern TAF
sides.

&&

.MARINE...
Issued at 333 AM AST Wed Nov 19 2025

A surface trough will continue to bring showers and isolated
thunderstorms across the local waters and passages today, likely
generating localized hazardous conditions for small craft.
Moderate easterly winds will persist through Wednesday night
before shifting to the northeast as a surface trough moves east of
the Leeward Islands. Pulses of a north- northeasterly swell will
continue to spread across the Atlantic waters and local passages
today, fading late tonight.

&&

.BEACH FORECAST UPDATE...
Issued at 1106 AM AST Wed Nov 19 2025

Based on buoy observations, the high rip current risk was extended
through Thursday afternoon. Pulses of the north-northeasterly
continue to arrive across the CWA, promoting hazardous conditions
for beachgoers along northern and eastern beaches of Puerto Rico,
Culebra, and St. Croix in the U.S. Virgin Islands. Another pulse
is expected to arrive tonight and peak around Thursday morning.

Then, as that pulse continues to fade, beach conditions will
improve by late Thursday night, with a moderate risk of rip
currents prevailing across the northern and eastern beaches of PR,
Vieques, Culebra, and the U.S. Virgin Islands. Nevertheless,
beachgoers are encouraged to swim near a lifeguard as life-
threatening rip currents are possible along the surf zone.

Aside from rip currents, beachgoers should be also aware of other
potential hazards such as lightning and gusty winds due to shower
and thunderstorm activity this afternoon and tomorrow that may
move over coastal areas. If thunder roars, stay indoors!

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Thursday afternoon for PRZ001-002-
     005-008-012.

VI...High Rip Current Risk through Thursday afternoon for VIZ002.

AM...None.
&&

$$

MRR/YZR