textproduct: San Juan

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.