textproduct: San Juan

UPDATE

A long period NNW swell will gradually build seas up to 7 feet and occasionally higher from late tonight through Thursday across the Atlantic waters. This swell will result in large braking waves along the north facing beaches of PR, including Culebra, and the northern USVI. Therefore, a High Rip Current Risk will be in effect on Thursday for these areas. A Small Craft Advisory is now in effect for the offshore Atlantic waters until Thursday afternoon. Additional coastal zones could be added to the SCA as offshore buoys indicated this afternoon seas 1-2 ft higher than model data.

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

KEY MESSAGES... Issued at 202 PM AST Wed Apr 22 2026

* Marine and beach conditions will gradually deteriorate tonight and tomorrow, Thursday, resulting in hazardous seas and life- threatening rip currents.

* An increasing risk of flooding across the north and west areas of Puerto Rico is expected by the end of the week and into the upcoming workweek.

* Heat indices around or exceeding 100 degrees are expected Sunday onwards.

* The primary hazards for the U.S. Virgin Islands will be a high risk of rip currents for the northern territories on Thursday, followed by a moderate risk over the next several days, along with a gradually increasing risk of heat toward the end of the forecast period across all islands.

Short Term(This evening through Friday)... Issued at 202 PM AST Wed Apr 22 2026

Mostly sunny skies prevailed across Puerto Rico and the U.S. Virgin Islands during the morning hours, becoming variably cloudy by the afternoon. Maximum temperatures reached the mid-80s along coastal areas and the mid to upper 70s across higher elevations. Northeasterly winds of 5 to 10 mph were observed. Limited afternoon convection is expected across southern and southwestern Puerto Rico later today, with activity dissipating around sunset.

Low-level moisture is forecast to steadily increase throughout the period, reaching values near 1.75 inches from Friday afternoon into Saturday morning. This moisture surge is associated with the remnants of an old frontal boundary north of the region and a trough deepening across the tropical western Atlantic. However, most of the moisture will remain confined below 750 mb. At lower levels, a weakening high-pressure system over the central Atlantic will gradually shift eastward, allowing an east-southeasterly wind flow to become established across the local islands. This pattern will advect deeper moisture into the region.

As a result, the available moisture combined with daytime heating will support a more active convective regime, increasing the risk of localized flooding, particularly toward the latter part of the forecast cycle. On Thursday, convection is expected to concentrate across central, southern, and southwestern Puerto Rico before shifting to central, north and northwestern areas on Friday. With the southeasterly wind flow, temperatures are expected to rise into the 90s, with heat indices approaching 100F on Friday.

Long Term(Saturday through next Tuesday)... Issued at 212 AM AST Wed Apr 22 2026

A surface high-pressure system positioned over the central Atlantic, east of the Lesser Antilles, is expected to continue migrating further eastward through early next week. As this system moves away, winds will shift toward a more southerly flow, drawing tropical moisture from the warm Caribbean waters into the region. At the same time, lingering moisture from the remnants of a frontal boundary will persist across the area through the upcoming weekend. This atmospheric setup will drive daytime temperatures above normal, particularly across coastal and urban areas of Puerto Rico and the U.S. Virgin Islands. The combination of intense heat and abundant moisture is expected to rise heat indices to 100F or higher.

While the weekend may see variable conditions, as pockets of drier mid-level air arriving intermittently could limit widespread rain, the combination of daytime heating and sea breeze convergence will still likely trigger isolated to scattered afternoon thunderstorms. This activity will be most concentrated over the interior and northern regions, bringing the risk of frequent lightning, gusty winds, and localized urban flooding.

By Monday afternoon into Tuesday, a deeper plume of moisture is expected to arrive. The environment will become increasingly unstable due to the arrival of this moisture alongside an upper- level trough, likely leading to more widespread shower and thunderstorm activity than over the weekend. While passing showers remain a threat for all the islands, the most active rainfall is expected over the interior and the western to northwestern portions of Puerto Rico during the afternoon hours. Residents and visitors, particularly those in flood-prone areas, are encouraged to monitor weather conditions closely and remain aware of potential rapid river rises and localized flooding through the midweek.

AVIATION... (18Z TAFS) Issued at 202 PM AST Wed Apr 22 2026

VFR conditions will continue to prevail at all TAF sites throughout the forecast cycle, with brief MVFR conditions possible at JPS through 22/22z in VCSH. The prevailing winds should remain from E-NE at 5 to 10 kts, with gusts around 15 knots and some sea breeze variations, becoming light and variable overnight.

MARINE... Issued at 710 PM AST Wed Apr 22 2026

A surface high pressure extending from the Central into Eastern Atlantic is interacting with a frontal boundary approaching from the western Atlantic, promoting light to moderate northeasterly winds. A long-period north-northwesterly swell is expected to arrive tonight and spread across the local Atlantic waters, resulting in hazardous conditions for small craft. Although the swell will diminish by late Thursday night into Friday, another long-period swell from the north-northeast should arrive on Saturday, however, seas are expected to remain below small craft advisory criteria.

BEACH FORECAST... Issued at 202 PM AST Wed Apr 22 2026

The moderate risk of rip currents continues across northern and eastern Puerto Rico, a low risk elsewhere. Beachgoers are encouraged to exercise caution, as life-threatening rip currents are possible along the surf zone. Tonight, a long-period north-northeasterly swell will arrive and spread across local Atlantic waters, with seas increasing between 5 and 7 feet. The latest report from NDBC buoy 41043 showed seas around 4 feet, with a period of 11-12 seconds. Taking into account swell decay and bathymetry, breaking waves between 5 and 7 feet can be observed along the northern exposed beaches of Puerto Rico and the U.S. Virgin Islands. Hence, a Rip Current Statement has been issued for the northern beaches of Puerto Rico, Culebra, and St. Thomas and St. John in the U.S. Virgin Islands from 6 AM AST through 6 PM AST Thursday. Residents and visitors are encouraged to check the beach forecast before going out and follow the advice of flags, signs, and beach patrols. Another long-period swell will likely arrive on Saturday, bringing back hazardous conditions for beachgoers. For additional information and location-specific rip current details, please visit weather.gov/beach/sju.

SJU WATCHES/WARNINGS/ADVISORIES

PR...High Rip Current Risk from 6 AM AST Thursday through Thursday afternoon for PRZ001-002-005-008-010-012.

VI...High Rip Current Risk from 6 AM AST Thursday through Thursday afternoon for VIZ001.

AM...Small Craft Advisory from midnight tonight to 6 PM AST Thursday for AMZ711.