textproduct: San Juan

KEY MESSAGES

Updated at 431 AM AST Tue May 26 2026

* Breezy to locally windy easterly winds will continue today, with the strongest gusts across coastal areas and the local islands. Winds should gradually ease later today into tonight.

* Hazardous marine and coastal conditions will persist through at least tonight into Wednesday. Small Craft Advisories remain in effect for most local waters, and a high risk of rip currents continues for many north-, east-, and southeast-facing beaches.

* Passing showers will affect windward coastal areas and the local islands at times, especially during the morning hours, producing brief ponding of water on roadways and in poor drainage areas.

* Afternoon showers and isolated thunderstorms are expected across interior and western to northwestern Puerto Rico today. Urban and small stream flooding will be possible with the heaviest activity.

* Warm to hot conditions will continue through the workweek, with limited to locally elevated heat risk possible across urban and coastal areas, particularly by the end of the week into the weekend. Traces of Saharan dust may also filter into the region later in the week.

Short Term(Today through Thursday)

Issued at 431 AM AST Tue May 26 2026

Frequent showers were observed across the local waters and portions of the islands during the overnight hours, as a surge of moisture moved across the northeastern Caribbean. Gusty wind conditions also continued through the night, with many weather stations, particularly across northeastern Puerto Rico and the smaller islands, reporting wind gusts in the upper 20s to mid-30s mph range. This trend is expected to persist through the morning hours, with showery weather conditions capable of producing ponding of water on roadways and in poorly drained areas in windward coastal areas. Breezy to locally windy conditions will continue today, but winds should gradually diminish as the pressure gradient across the northeastern Caribbean loosens.

The latest guidance and satellite-derived moisture fields continue to show above-normal moisture across the region today through Wednesday. The 700-500 mb relative humidity will remain elevated through at least Wednesday, supporting periods of passing showers embedded in the trades. In addition, troughiness aloft will maintain relatively cool 500 mb temperatures near -8 to -9 degrees Celsius and steeper 700-500 mb lapse rates, which will help enhance instability. Therefore, as this moisture combines with daytime heating, sea breeze convergence, and local effects this afternoon, shower development is expected across interior and western to northwestern Puerto Rico, with isolated thunderstorms also possible. These heavy showers could produce urban and small stream flooding, although faster steering winds could somewhat limit overall rainfall accumulations, unless storm dynamics allow for storm redevelopment and/or backbuilding that could enhance rainfall accumulations across western and northwestern Puerto Rico.

A similar pattern is expected on Wednesday, as above-normal moisture persists over the local area. Passing showers will continue to affect windward and eastern sections of Puerto Rico and the U.S. Virgin Islands at times, especially during the overnight and morning hours. By the afternoon, diurnal heating and local effects will once again promote shower and isolated thunderstorm development across interior and western Puerto Rico, although winds will be somewhat weaker than today. Urban and small stream flooding will remain possible with the strongest and most persistent activity.

By Thursday, a slight decrease in moisture is expected as precipitable water values trend closer to normal and mid-level relative humidity begins to decrease. However, lingering moisture and local effects will still support passing showers across eastern Puerto Rico and the U.S. Virgin Islands during the morning, followed by afternoon convection across interior and western Puerto Rico. Traces of suspended Saharan dust are also expected to filter into the region, which may result in hazy skies and could limit shower coverage somewhat compared to today and Wednesday. Meanwhile, southeasterly flow and warm 925 mb temperatures will promote limited to locally elevated heat risk across urban and coastal areas, especially where winds become lighter and cloud cover is reduced.

Long Term(Friday through Tuesday)

Issued at 431 AM 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

(06Z TAFS) Issued at 431 AM AST Tue May 26 2026

Mainly VFR conds expected to prevail across all terminals. However, passing SHRA may lead to brief MVFR conds, especially across TJSJ/TIST/TISX thru the morning hrs. SHRA/TSRA expected to develop ovr the interior and W/NW PR this aftn, which may result in brief MVFR/IFR conds at TJBQ. Mtn obsc psbl ovr interior PR this aftn. Low- lvl winds will continue fm the E-ESE at 10-15 kt, with gusts around 20-25 kt, especially across the USVI and N PR terminals. Winds will gradually diminish aft 23Z, bcmg 5-10 kt overnight.

MARINE

Issued at 431 AM AST Tue May 26 2026

Small Craft Advisories remain in effect for the Atlantic waters through midnight and for the local passages through this afternoon as moderate to locally strong easterly winds continue to generate choppy to rough seas of up to 7 feet. These hazardous conditions are being driven by a strong high pressure system over the central Atlantic maintaining a tight pressure gradient across the northeastern Caribbean. 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 431 AM AST Tue May 26 2026

A high risk of rip currents, meaning life-threatening rip currents are likely in the surf zone, will continue through tonight for the northern, eastern, and southeastern beaches of Puerto Rico, as well as Vieques, Culebra, and the U.S. Virgin Islands. Therefore, a Rip Current Statement remains in effect. A moderate risk of rip currents, meaning life-threatening rip currents are possible in the surf zone, will persist across the remaining local beaches. Beachgoers should heed the advice of local officials and beach safety personnel.

Beginning Wednesday, the rip current risk is expected to gradually decrease as winds subside. However, a moderate risk of rip currents will likely continue along many northern and eastern exposed beaches through the latter part of the week. Looking ahead to next weekend, forecast guidance suggests strengthening winds could once again increase and expand the rip current risk across local beaches. In addition, afternoon thunderstorms are expected to develop each day across western Puerto Rico and may produce dangerous cloud-to-ground lightning. If thunder is heard, move indoors immediately and remain sheltered until the storm passes.

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.

Small Craft Advisory until noon AST today for AMZ716-723-726-733- 741.