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090
FXCA62 TJSJ 081735
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
135 PM AST Wed Apr 8 2026

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

.KEY MESSAGES...
Updated at 135 PM AST Wed Apr 8 2026

* A moderate risk of rip currents will prevail tonight, likely
  increasing to a high risk from Thursday onward due to pulses of
  swells.

* Generally stable weather conditions are expected, with isolated
  showers over eastern areas of Puerto Rico during the nights and
  mornings, then shifting to the northwestern quadrant during the
  afternoons.

* For the U.S. Virgin Islands, mostly sunny conditions are expected,
  with isolated showers from time to time.

* Near-normal to above-normal temperatures will persist through at
  least next Sunday.

* From Friday onward, seas will remain around 4 to 6 feet, and
  small craft will need to exercise caution across the Atlantic
  waters and local passages.

&&

.Short Term(This evening through Friday)...
Issued at 135 PM AST Wed Apr 8 2026

A stable weather pattern prevailed during the morning hours with no
shower activity at all across the CWA. Mostly clear skies prevailed
across western sections of the islands, and the eastern sections
observed some partly cloudy skies without shower activity.  Those
conditions leave the islands with a really good weather day, with
plenty of sunshine, allowing daytime temperatures to rise into the
lower 90s across north central sections and into the upper 80s along
the rest of the coast. In terms of heat indices, the islands
experience warm days with values surpassing 100 degrees, especially
in the north central, where unofficial weather stations report heat
indices of 108.

By late tonight, model guidance suggests a weak wind perturbation
moving over Puerto Rico. This feature may prolong afternoon showers,
particularly across southwestern Puerto Rico, as backing winds
develop with a prefrontal trough lifting north of the area. This
surface evolution will promote a more easterly wind flow beginning
early tomorrow and persisting through Friday morning, allowing for
some moisture patches to move across the local waters and
occasionally reach eastern Puerto Rico and the U.S. Virgin Islands.
For the remainder of the period, stable weather conditions are
expected as a strong mid-level (700 mb) ridge builds over the
islands, eroding available moisture and promoting warming aloft. At
upper levels, the region will remain under the convergent side of an
upper-level trough, further supporting stable conditions. Therefore,
Thursdays forecast will remain on the stable side, with limited
morning shower activity and brief, localized afternoon showers
mainly over the western interior, resulting in little to no flooding
threat. Any showers that do develop are expected to be short-lived
due to subsidence aloft and limited instability, with minimal
accumulation overall.

On Friday, some instability will move in as the upper-level trough
just on top of the islands moves further eastward, locating the
divergence and favorable side just over us. However, at 500 MB, a
clear mid-level ridge will still limit vertical development. At the
surface, winds will return from the east-southeast, and precipitable
water values will drop into the 25th percentile compared to the
climatological normal. Given the expected conditions, Friday looks
like a really good day with very limited shower activity, and even
the Glvez-Davison Index (GDI) doesn`t show any thunderstorm
development. As a result, the rainfall probability remains low.
However, very short-lived showers can develop in isolated areas,
with rainfall accumulations.

&&

.LONG TERM(Saturday through Wednesday)...
Issued at 327 AM AST Wed Apr 8 2026

Conditions will remain near seasonal values for this time of year on
Saturday. Periods of passing showers are expected during the morning
hours across eastern Puerto Rico and the U.S. Virgin Islands,
followed by afternoon convection over western Puerto Rico. At this
time, limited ponding of water is expected across western Puerto
Rico on Saturday.

Beginning Sunday, conditions will gradually become more unstable as
an approaching deep-layered trough, combined with above-normal
moisture, supports increasing shower and thunderstorm activity
across the region. Model guidance continues to suggest a transition
toward a wetter and more unstable pattern.

At this time, the wettest period is expected from Monday into
Tuesday, when widespread showers and thunderstorms will be more
likely. However, given the extended forecast range, confidence
remains moderate regarding the magnitude of the potential flooding
and lightning threats.

By midweek, conditions should gradually return to near-normal for
this time of year, although lingering moisture may continue to
support scattered shower activity across the islands.

&&

.AVIATION...
(18Z TAFS)
Issued at 135 PM AST Wed Apr 8 2026

Mainly VFR conds are expected across TAF sites this forecast
period. The site with the greater chance to observe SHRA and VCTS
is TJBQ from 08/18Z thru 08/22Z. This could result in intermittent
periods of MVFR conds due to lower cigs and reduced vis. Winds
will continue mainly from the SE at around 10 to 15 kts and gusts
around 20 to 25 mph and sea breeze variations. Lighter winds
returning aft 08/23Z with increasing potential of VCSH across
eastern TAF sites.

&&

.MARINE...
Issued at 135 PM AST Wed Apr 8 2026

Moderate southeasterly trade winds will persist tonight across
most waters, while moderate to locally fresh across the local
Caribbean passages. Afterward, a broad surface high-pressure
system extending from the central Atlantic will maintain moderate
trade winds across the regional waters through the weekend. A
2-foot, long-period northeasterly swell will move into the local
waters from late tonight through Thursday, followed by a 4-foot
north to northwest swell beginning Friday. These swells will
generally keep seas at 4 to 6 feet, with small craft advised to
exercise caution, particularly across the Atlantic waters and
local passages.

&&

.BEACH FORECAST...
Issued at 135 PM AST Wed Apr 8 2026

Tonight, a moderate risk of rip currents will prevail across
north-facing beaches of Puerto Rico, Culebra, Vieques, and the
U.S. Virgin Islands. This means life-threatening rip currents are
possible in the surf zone, so beachgoers should remain cautious.
However, a small but long-period northeasterly swell will arrive
late tonight into tomorrow, likely increasing the risk of life-
threatening rip currents along the northern and eastern beaches of
Puerto Rico, Culebra, and the northern U.S. Virgin Islands.

Another swell from the north to northwest is expected to spread
across the Atlantic waters and surrounding passages starting
Friday and continuing onward, keeping a high risk of life-
threatening rip currents in place through the weekend. Continue to
monitor the forecast for upcoming alerts and visit weather.gov/beach/sju
for additional details.

&&

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

$$

SHORT TERM...LIS
LONG TERM...MMC
AVIATION/MARINE/BEACH...YZR

NWS SJU Office Area Forecast Discussion