645
FXCA62 TJSJ 221857
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
257 PM AST Sun Mar 22 2026

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

.KEY MESSAGES...
Issued at 255 PM AST Sun Mar 22 2026

* Variable weather conditions will persist through the rest of the
  afternoon and evening due to a frontal boundary over the area.
  Expect cloudy skies and periods of shower activity, at times
  heavy, with a localized flooding threat, mainly over the eastern
  third of Puerto Rico, Vieques, and Culebra.

* For the U.S. Virgin Islands, most of the afternoon activity will
  focus on St. Thomas and St. John. However, shower activity over
  St. Croix is expected to increase this evening and overnight as
  the frontal boundary approaches.

* The remnants of the frontal boundary will continue to move over
  the area during the next few days, resulting in variable weather
  conditions, particularly across eastern Puerto Rico and the
  smaller islands.

* A high risk of rip currents along the northern coastal areas,
  from Mayagez to Fajardo, will persist through at least late
  tonight. A Small Craft Advisory remains in effect for the
  offshore Atlantic waters through tomorrow.

&&

.Short Term(This evening through Tuesday)...
Issued at 255 PM AST Sun Mar 22 2026

Variable to locally unsettle conditions were observed during the
morning under cloudy skies as a frontal boundary had been moving
across the region. The 12Z TJSJ sounding indicated approximately
2.05 inches of precipitable water. Satellite-derived imagery shows
that moisture levels remain in the 75th percentile, which is
above normal for this time of year. Radar estimates indicate
maximum rainfall accumulations ranging from 1.5 to 2 inches, with
isolated amounts up to 3 inches across some northern and southern
areas of Puerto Rico. These conditions prompted the issuance of a
few Flood Advisories during the morning hours, however, no reports
have been received at this time. Across the USVI, rainfall totals
have been lower, generally under 0.60 inches. The rest of the
day the weather conditions are expected to remain variable
through the rest of the afternoon and evening due to a frontal
boundary over the area. Cloudy skies and periods of shower
activity, at times heavy, with a localized flooding threat, mainly
over the eastern third of Puerto Rico, Vieques, and Culebra.

By Monday, as the upper-level trough and surface front shift
farther east and remnant moisture from the frontal boundary will
linger over the region, including Culebra, Vieques, and the U.S.
Virgin Islands. This moisture, combined with local influences,
will produce intermittent showers moving in and out of coastal
areas in these locations. Meanwhile, winds will continue from the
north to northeast steering most of the showers across eastern
Puerto Rico and nearby coastal waters, where a limited flood
risk will persist. By Tuesday, winds at the surface will shift to
come from the east as a high pressure builds over the central
Atlantic. Moisture remaining in the area will promote the
continuation of variable weather conditions, particularly across
eastern Puerto Rico and the smaller islands.

&&

.LONG TERM(Wednesday through Sunday)...
Issued at 300 AM AST Sun Mar 22 2026

Moisture is expected to increase by mid-week as model guidance
indicates precipitable water (PW) values rising to between 1.50 and
2.00 inches, near the 75th percentile for this time of year and
therefore above normal. A weak mid- to upper-level trough moving
through the region, along with a weak surface perturbation, will
promote increasing cloud cover and frequent periods of showers.
Temperatures at 500 mb are forecast to be near 7 degrees C,
suggesting a moderate potential for instability. This could support
occasional heavier showers, although widespread organized convection
is not anticipated. The enhanced cloud cover will limit daytime
heating, keeping high temperatures near typical seasonal values for
March. Winds should remain generally light to moderate, with locally
higher speeds possible in and near shower activity. These unsettled
conditions are expected to persist through the end of the work week.

By the weekend, a gradual transition toward a drier airmass is
anticipated to filter across the islands, leading to decreasing
shower coverage and clear to partly cloudy skies. Despite the drying
trend, temperatures should remain relatively comfortable and
consistent with March.

&&

.AVIATION...
(18Z TAFS)
Issued at 255 PM AST Sun Mar 22 2026

Periods of MVFR/brief IFR conds possible in SHRA, with reduced
VIS and lower CIGs (BKN/OVC010-020) are expected thru the next few
hours, mainly across TJSJ and TJPS. SHRA/VCTS developing aft
23/03Z, becoming more frequent ovr USVI TAF sites and TJSJ. Monday
morning, TJPS & TJSJ are expected to observe additions -RA, as
showed with PROB30s. Mainly N to NE winds at around 10 to 15 kts,
becoming lighter aft 22/23Z.

&&

.MARINE...
Issued at 255 PM AST Sun Mar 22 2026

A frontal boundary has moved across the region, leaving behind
unsettled marine conditions with lingering showers and a slight
chance of thunderstorms across the local waters. A weak long-period
northerly swell will result in hazardous seas across the Atlantic
waters. In the wake of the boundary, moderate to locally fresh
northerly winds are producing choppy seas, particularly across the
Mona Passage and offshore Atlantic waters. A surface high-pressure
system building over the western to central Atlantic will maintain
northeasterly winds through early this week, with increasing winds
and seas expected by midweek.

&&

.BEACH FORECAST...
Issued at 255 PM AST Sun Mar 22 2026

Life-threatening rip currents are likely along the north-facing
beaches of Puerto Rico (from Rincn to Fajardo), with a moderate
risk of rip currents across Culebra and the U.S. Virgin Islands.
Beachgoers should remain cautious, stay near lifeguards, and avoid
entering the water if unsure of conditions. Lower risk conditions
are expected along the more protected southern beaches, though
caution is still advised.

In addition, lingering moisture and instability behind a recently
passed frontal boundary will continue to promote showers throughout
the day and into tonight. Localized impacts, such as reduced
visibility and brief gusty winds, may occur near showers, creating
sudden hazardous conditions for beachgoers. A limited thunderstorm
risk remains, and any storms that develop could produce lightning,
posing a danger to those in or near the water. If thunderstorms
approach, seek shelter immediately.

For additional information and location-specific rip current
details, please visit: weather.gov/beach/sju.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late tonight for PRZ001-002-005-
     008-010.

VI...None.
AM...Small Craft Advisory until noon AST Monday for AMZ711.

&&

$$

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

NWS SJU Office Area Forecast Discussion