906
FXCA62 TJSJ 191811
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
211 PM AST Sun Apr 19 2026

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

.KEY MESSAGES...
Updated at 211 PM AST Sun Apr 19 2026

* Limited flooding risk each afternoon, driven by locally induced
  convection.

* Isolated thunderstorms possible each afternoon, producing
  lightning and brief gusty winds.

* Choppy, wind-driven seas persist through Monday, subside
  Tuesday, then build again Wed-Thu with increasing seas and a
  northerly swell.

* Moderate rip current risk most days, increasing to high WedThu
  along north and east-facing beaches.

&&

.Short Term(This evening through Tuesday)...
Issued at 211 PM AST Sun Apr 19 2026

A drier and more stable pattern will continue across Puerto Rico and
the U.S. Virgin Islands tonight. The upper-level trough has moved
east of the area, allowing drier air aloft and less favorable
conditions for deep thunderstorm development. At the surface, high
pressure over the North Atlantic will maintain a generally easterly
wind flow. This will keep some low-level moisture in place, but
overall moisture will become more shallow, mainly below 700800 mb.
Expect mostly fair conditions tonight, with only brief passing
showers across eastern Puerto Rico, the U.S. Virgin Islands, and
nearby waters.

The drier pattern will continue into Tuesday as winds weaken and
become east to east-southeasterly during the morning. By the
afternoon, winds will begin to shift from the northeast, helping
steer locally induced convection toward southwestern and southern
Puerto Rico. Despite reduced moisture, sufficient low-level moisture
and daytime heating will support locally scattered showers and
isolated thunderstorms, with activity diminishing during the
evening. Overnight, mainly fair conditions will prevail, with brief
passing showers across windward areas.

Flooding risk will remain limited, but some localized impacts are
still possible. Brief heavy showers could lead to ponding of water
on roads and in poor drainage areas, as well as minor urban and
small stream flooding. This is more likely in areas where soils
remain wet from recent rainfall. Some rivers remain elevated and
could respond quickly to additional rainfall. Isolated thunderstorms
may also produce lightning and brief gusty winds. Overall, impacts
should remain localized and mainly during the afternoon hours.gh
increasing to above normal at times under the southerly flow.

&&

.LONG TERM(Wednesday through Sunday)...
Issued at 131 AM AST Sun Apr 19 2026

A shift towards relatively drier and more stable conditions is
forecast to start the long term period with seasonal Precipitable
Water (PWAT) values. PWAT values are forecast to generally stay at
normal, though periods of high-end normal to above-normal values are
possible as moisture is steered towards from the Caribbean to the
region. A series of surface highs and frontal lows will dominate the
local wind pattern, maintain light to moderate northeasterly, then
southeasterly, then southerly and then southwesterly winds during
the period. Local weather will be seasonal. Expect passing showers
over windward sectors during the morning and afternoon hours. The
focus of afternoon convective activity will vary in location each
day. On Wednesday and Thursday, interior to southwestern Puerto
Rico. On Friday and Saturday, interior to northern Puerto Rico. On
Sunday, north-central to northeastern Puerto Rico. The combination
of available moisture, daytime heating, and local effects could lead
to moderate to heavy rainfall and isolated thunderstorms during
these afternoon periods. Temperatures at the 500 mb level are
forecast to remain seasonal. Isolated thunderstorms are forecast
each afternoon, particularly toward the end of the period due to a
nearby mid-to-upper trough. Temperatures at 925 mb will also stay
seasonal throughout most of the period, although increasing to above
normal at times under the southerly flow.

&&

.AVIATION...
(18Z TAFS)
Issued at 211 PM AST Sun Apr 19 2026

Mainly VFR conds across all TAF sites, with the exception of brief
MVFR due to VCTS/SHRA thru 19/22Z across TJBQ. Prevailing E winds
at around 10 to 15 kts with gusts up to 25 kts and sea breeze
variations for the same period. Then, becoming lighter aft 19/23Z
and increasing again around 20/13Z. VCSH across TIST/TISX/TJSJ
during the overnight period.

&&

.MARINE...
Issued at 211 PM AST Sun Apr 19 2026

A surface high pressure over the Atlantic is promoting moderate
to locally fresh easterly winds, particularly across the offshore
Atlantic waters and local Caribbean passages resulting in moderate
to choppy seas through Monday. Small craft operators should
exercise caution in those areas. Seas slightly subside around
Tuesday, then build up to 6 to 7 feet by mid-week onward due to a
northerly swell spreading across the Atlantic waters.

&&

.BEACH FORECAST...
Issued at 211 PM AST Sun Apr 19 2026

A moderate risk of rip currents will persist long the north-
facing beaches of Puerto Rico, Culebra, and the U.S. Virgin
Islands through Monday due to wind-driven seas. That means life-
threatening rip currents are possible in the surf zones and
beachgoers are encouraged to remain cautious. As winds become
lighter by Tuesday afternoon into Wednesday, the risk is expected
to decrease to low along beaches of USVI and Culebra. By Thursday,
the risk is anticipated to potentially increase to high along the
northern coastline of Puerto Rico as a northerly swell spreads
across the Atlantic waters.

Also, be aware of thunderstorms each afternoon. Remain weather-
aware due to rapidly changing conditions, and be prepared to seek
shelter if you hear thunder.

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

&&

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

$$

SHORT TERM...ICP
LONG TERM...MRR
AVIATION/MARINE/BEACH...YZR

NWS SJU Office Area Forecast Discussion