textproduct: San Juan

KEY MESSAGES

Updated at 1230 PM AST Tue May 26 2026

* Wet and unstable weather is forecast for the rest of the afternoon hours into the night. Therefore, residents can expect periods of cloudiness with some moderate to locally heavy showers. * Hazardous coastal conditions remain in place across the entire north and east coasts of Puerto Rico, including the municipalities of Culebra and Vieques, as well as the U.S. Virgin Islands. Beachgoers are urged to remain out of the affected coastal areas for security reasons.

* Hazardous marine conditions will continue due to wind-driven seas between 6 and 8 feet across the offshore and nearshore Atlantic waters.

* Saharan dust particles are expected from Thursday into Saturday along the islands, but an even bigger pulse is forecast from Monday into Tuesday from the upcoming workweek.

Short Term(This evening through Thursday)

Issued at 1230 PM AST Tue May 26 2026

Cloudy skies and periods of showers affected Puerto Rico and the U.S. Virgin Islands during the day, with scattered thunderstorm activity observed across the local waters. Moisture content remained elevated, with satellite-derived PWAT values near 1.94 inches supporting the unsettled pattern. Meanwhile, breezy easterly winds promoted windy conditions along coastal areas and local waters throughout the day. As of 1 PM, showers were observed along several sections of Puerto Rico, but rainfall accumulations were limited at that time. Despite the cloud cover and passing showers, temperatures remained generally within seasonal normal across the islands, ranging in the low to upper 80s across the coastal areas, and across the mountain sections, temperatures were in the low 80s.

For the rest of today into tonight, abundant low-level moisture will continue to stream across the forecast area under prevailing easterly winds, maintaining cloudy periods and passing showers across the local waters and windward sectors of Puerto Rico and the U.S. Virgin Islands. Although the deepest convection is expected to remain mostly over the surrounding waters overnight, periods of moderate showers will continue to move across portions of eastern Puerto Rico, the U.S. Virgin Islands, and nearby coastal municipalities at times. At upper levels, a tilted trough combined with favorable divergence aloft near 250 mb will continue to support instability across the northeastern Caribbean. These conditions will enhance shower development and support isolated thunderstorms mainly across the offshore waters and nearby coastal areas through tonight. Winds will remain from the east at moderate to locally fresh. Overnight temperatures are expected to remain in the seasonal normals with low 80s into upper 70s across the coastal areas and slightly fresh across the mountains.

On Wednesday into Thursday, a broad surface high pressure extending from the western Atlantic into the Caribbean will continue to promote east to east-southeasterly winds across the local islands. This wind flow will maintain a warm weather pattern across Puerto Rico and the U.S. Virgin Islands with heat indices that could reach 105 to 111 degrees. Moisture will remain abundant through the period, with the ECMWF and the GFS model guidance indicating deep moisture across the islands, with PWAT values ranging from 2.12 inches by Thursday being in the 75th percentile. Temperatures at 500 mb will drop into the -8 to -9 degrees Celsius will continue to provide enough instability to support locally heavy showers. Therefore, the indicator, the Glvez-Davison Index (GDI), continues to indicate favorable conditions for afternoon convection and isolated thunderstorm development, especially across the interior and western sections of Puerto Rico each afternoon. The surface winds will support warmer temperatures across northern and coastal areas in Puerto Rico. Across the U.S. Virgin Islands, shower activity is expected to remain more limited and mainly focused during the overnight and morning hours with passing trade wind showers. By Thursday, some dryness is expected as a pulse of Saharan dust will gradually arrive across the region, resulting in hazy skies, reduced visibility at times, and a gradual decrease in shower coverage toward the end of the period.

Long Term(Friday through next Monday)

Issued at 1230 PM AST Tue May 26 2026

The long-term forecast remains on track from Friday through Tuesday as the broad surface high pressure at the Central Atlantic remains the main weather feature during the period. On Thursday, available moisture from a previous easterly wave will persist across the islands with precipitable water values from 1.8 to 2.0 inches, remaining in the normals for the season. This moisture will be enough to develop another moisture and wet day with variable morning followed by afternoon convection along the northwestern quadrant. On Friday, southeasterly winds will persist as the broad surface high pressure expands even more to the east Atlantic. Under this pattern, some of the moisture from the previous day will lift slightly more into the north, leaving the islands with moisture with PWAT values generally between 1.60 and 1.80 inches. The lack of abundant moisture and cloudiness will enhance warmer daytime temperatures, allowing heating indices up to 108 degrees as suggested by the 925 MB temperature model guidance variable. As a result, warm daytime conditions are expected each day, particularly across northern, western, and urban coastal sections of Puerto Rico. Although a drier, more stable weather pattern is expected overall, local effects and diurnal heating will continue to support isolated afternoon convection from Friday into Sunday, mainly across the northwestern quadrant of Puerto Rico. Brief periods of moderate rainfall, ponding of water on roads, isolated lightning strikes, and gusty winds will remain possible with the strongest activity.

By Monday into Tuesday, both the GFS and ECMWF continue to suggest a significant drying trend across the northeastern Caribbean as a significant Saharan Air Layer intrusion spreads across the region. Furthermore, the NASA Goddard Earth Observing System model indicates high dust concentrations ranging between 0.40 and 0.45, supporting widespread hazy skies and poor air quality across the local islands. This pattern will result in very dry atmospheric conditions, limited thunderstorm activity, and limited rainfall activity across most of the forecast area. Shower activity will mainly remain short-lived across western Puerto Rico due to local effects. In addition, warm to hot and hazy conditions are expected through early next week as southeasterly winds continue to support a warming trend across the region. Therefore, the forecast calls for elevated heat indices and limited rainfall through at least Tuesday.

AVIATION

(18Z TAFS) Issued at 1230 PM AST Tue May 26 2026

Sct SHRA/TSRA across PR could lead to tempo MVFR conds at TJSJ/TJBQ thru 26/22z. Mtn tops obscd and BKN cigs btw FL025-050 are expected. Mostly VFR with VCSH expected across the USVI terminals. Strong E winds btw 16-22 kt with gusts up to 30 kt expected to continue thru 26/22z, decreasing 8-14 kt overnight.

MARINE

Issued at 1230 PM AST Tue May 26 2026

A broad surface high pressure in combination with a stationary frontal boundary across the central Atlantic will continue to result in moderate to locally strong easterly winds. This pattern will allow wind-driven seas to generate choppy to rough seas of up to 8 feet. Therefore, there is a small craft advisory in effect across all the Atlantic & Caribbean local waters, including the local passages (Mona & Anegada). Conditions are expected to gradually improve during the second half of the week as winds decrease and seas subside. Mariners should also remain alert for afternoon thunderstorms developing near the western coastal waters of Puerto Rico, which may produce locally higher winds, rough seas, and dangerous lightning.

BEACH FORECAST

Issued at 1230 PM AST Tue May 26 2026

Wind-driven seas due to a broad surface high pressure over the central Atlantic will continue to result in choppy seas along the coastal areas, with seas up to 7 feet and breaking waves from 5 to 7 feet. Therefore, there is a high risk of rip current across all northern, northeastern, and eastern coastal areas of Puerto Rico, Culebra, Vieques, and the U.S. Virgin Islands. A moderate risk of rip currents, meaning life-threatening rip currents are expected to continue across all the southern and western coasts of Puerto Rico. On Wednesday, conditions will gradually improve as winds diminish. However, a moderate risk of rip currents will likely continue along many northern and eastern exposed beaches through the latter part of the week. For the upcoming weekend, coastal conditions are forecast to deteriorate once again along the northern coastal areas of Puerto Rico.

SJU WATCHES/WARNINGS/ADVISORIES

PR...High Rip Current Risk through late tonight for PRZ001>003-005- 008-012-013.

VI...High Rip Current Risk through late tonight for VIZ001-002.

AM...Small Craft Advisory until midnight AST tonight for AMZ711-712.