019
FXCA62 TJSJ 270844
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
444 AM AST Tue Jan 27 2026

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

.KEY MESSAGES...
Issued at 437 AM AST Tue Jan 27 2026

* Small Craft Advisory and High Rip Current Risk are in effect
  today, as a northerly swell impacts the offshore Atlantic waters
  and northern exposed beaches.

* Hazardous seas and coastal conditions may return this weekend due
  to the arrival of another northerly swell, potentially affecting
  the Atlantic waters and north-facing coastlines.

* Passing showers will affect the islands at times with afternoon
  shower activities over western Puerto Rico. At most, ponding of
  water in roads and poorly drained areas.

* There is a medium chance of observing an increase in shower
  coverage and isolated thunderstorms this weekend as tropical
  moisture moves into the region, with a potential for locally
  heavy rainfall.

&&

.Short Term(Today through Thursday)...
Issued at 437 AM AST Tue Jan 27 2026

Mostly clear skies gave way to cool temperatures during the
overnight hours. Some places in the interior of Puerto Rico
registered values below 60 degrees. Coastal areas in the west had
lows in the mid and upper 60s, while eastern Puerto Rico and the
Virgin Islands saw values in the low and mid 70s. Some showers
managed to form across the Caribbean and Atlantic waters, but almost
no activity was detected over land areas.

The surface high that it`s driving the trade winds from the east
southeast is now centered over the eastern Atlantic. The gradient
has weaken since yesterday, and winds speeds should be at 10 to 15
mph. Aloft, a ridge is in placed over the central Caribbean, with
dry air in the mid levels. The most recent satellite derived
precipitable water imagery confirms that a small area of moisture
will cross the local islands today. Showers should increase a little
in the morning, mostly for eastern Puerto Rico and the Virgin
Islands. Since the patch of moisture should cross Puerto Rico at mid-
day, it is likely that some showers will develop along the interior
and west, leading to ponding of water in roadways and low lying
areas. Once this patch of moisture cross, conditions dry out quickly
tonight, with dew point depressions of 20 to 30 degrees Celsius
expected.

For tomorrow and Thursday, the atmosphere becomes more stable, with
500 mb temperatures about two standard deviation warmer than normal.
Regardless, the trade winds will continue to carry small patches of
moisture near the area. Tomorrow, the probability of precipitation
is about 30-40% for the Virgin Islands and eastern Puerto Rico, and
50% for western Puerto Rico in the afternoon hours. However,
accumulations are expected to be on the light side. Thursday looks
drier once again, at least in the morning and early afternoon hours.
Winds will become lighter, and coming from the south-southeasterly.
Thicknesses at 1000-850 mb will increase, and hence, it will feel
warmer too, with highs in the upper 80s in coastal and low elevated
areas.

&&

.Long Term(Friday through Tuesday)...
Issued at 437 AM AST Tue Jan 27 2026

The synoptic pattern will remain generally unchanged through the
long-term period, with a frontal boundary approaching the region
from the northwest. Southerly to southeasterly low-level flow ahead
of this boundary will continue, promoting above normal temperatures
across Puerto Rico and the U.S. Virgin Islands.

Based on the latest global model guidance, Friday is expected to be
the relatively less active day of the period, as deeper moisture
remains south of the area. Conditions are forecast to become
progressively wetter over the weekend as southerly flow strengthens
and begins to pull tropical moisture over the region, earlier than
indicated in previous model cycles.

Precipitable water values are forecast to increase beginning
Saturday, rising from near 1.3 inches on Friday to near or above 2.0
inches by Saturday and Sunday, which is well above normal for this
time of year. This increase in moisture will support higher shower
coverage and rainfall intensity, particularly during the weekend and
into early next week.

At upper levels, the region will be positioned between an upper-
level trough to the northwest and a ridge to the southeast, with
favorable dynamics aloft depending on the exact placement and
evolution of the trough. Nevertheless, sufficient instability may
remain in the vicinity, and when combined with daytime heating,
local effects, and sea breeze convergence, isolated thunderstorms
cannot be ruled out, mainly during the afternoon hours across
interior and northwest/northern Puerto Rico. Locally heavy rainfall
will be possible with the strongest convection.

Potential impacts include ponding of water in urban and poorly
drained areas, as well as localized urban and small stream flooding,
particularly from Saturday through Monday. Gusty winds may also
accompany heavier showers and any isolated thunderstorms.

&&

.AVIATION...
(06Z TAFS)
Issued at 437 AM AST Tue Jan 27 2026

Mainly VFR conditions expected to prevail. Moisture surge will
increase showers after 14Z along eastern PR/USVI. From 15-21Z, SHRA
will develop along the Cordillera Central, likely reaching TJPS at
times. Periods of reduced VIS and low ceilings can be expected.

&&

.MARINE...
Issued at 437 AM AST Tue Jan 27 2026

Winds are gradually easing as the surface high pressure shifts
farther east into the central Atlantic. Moderate to locally fresh
easterly winds will prevail through midweek turning light by the end
of the week. However, a northerly swell will result in hazardous
seas across the offshore Atlantic waters through this evening.
Looking ahead to next weekend, another long-period northerly swell is
expected to reach the regional Atlantic waters, which may result in
hazardous marine conditions once again, particularly across the
offshore Atlantic waters.

&&

.BEACH FORECAST...
Issued at 437 AM AST Tue Jan 27 2026

Breezy wind conditions across the regional waters are gradually
subsiding; however, a northerly swell is moving into the Atlantic
waters today. Buoy 41043 is already reporting a swell near 6 feet
with periods of 10 to 11 seconds. As a result, estimated breaking
waves of approximately 6 to 8 feet are anticipated along the
northern exposed beaches of Puerto Rico. These conditions will
support a High Risk of rip currents through at least this evening
for the north-facing beaches of the island.

Across the smaller islands, including Culebra, Vieques, and the U.S.
Virgin Islands, lingering swell energy will continue to maintain a
moderate to locally high risk of rip currents, especially along
north-facing and exposed beaches.

Beachgoers are strongly urged to follow local beach safety guidance
and avoid entering the water at beaches with posted high rip current
risk.

For localized and updated rip current information, visit
weather.gov/beach/sju.

&&

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

VI...None.
AM...Small Craft Advisory until 6 PM AST this evening for AMZ711.

&&

$$

SHORT TERM/AVIATION...ERG
LONG TERM/MARINE/BEACH....CVB

NWS SJU Office Area Forecast Discussion