textproduct: San Juan

KEY MESSAGES

Issued at 309 AM AST Mon Mar 23 2026

* A high risk of rip currents will persist across the northern and northeastern beaches of Puerto Rico until 6 PM AST this evening. A moderate risk will remain for the rest of the areas.

* Hazardous Marine conditions remain hazardous with seas up to 7 feet across the offshore Atlantic waters. Therefore, a Small Craft Advisory is in effect.

* A variable weather pattern will promote periods of passing showers, with light to moderate rainfall possible during the morning, followed by localized afternoon convection, especially across interior and western Puerto Rico.

* Across the U.S. Virgin Islands, variable conditions will prevail with passing showers moving in from the east, leading to brief reductions in visibility and occasional wet conditions throughout the day.

Short Term(Today through Wednesday)

Issued at 309 AM AST Mon Mar 23 2026

During the night into the early morning hours, mostly cloudy skies prevailed across most of the forecast area. Light to moderate shower activity was observed early in the morning across portions of the metropolitan area, specifically affecting municipalities from Loiza to Dorado. This shower activity was light and did not result in significant rainfall accumulations. Minimum temperatures overnight were slightly below normal values; across the coastal areas, temperatures fluctuated between the low to mid 70s, and in the mountainous sections, from the upper 50s to the lower 60s.

As the frontal boundary and the upper-level trough continue to move eastward out of the region, a deep layer of trapped moisture at 850 mb will be the main driver for a showery pattern today, with GOES-derived satellite imagery indicating precipitable water values ranging between 1.5 and 1.7 inches, remaining above normal climatological levels; this surface moisture will combine with local and diurnal effects to produce light to moderate passing showers in the morning, followed by more localized deep convection. Surface winds will remain from the northeast as a surface high-pressure system over the western Atlantic extends into the Caribbean, a pattern that will favor shower development around 12 PM across northeastern sections of the island before shifting toward the southwestern quadrant of the region. Given that instability has decreased, widespread thunderstorm activity is not expected; however, one or two isolated thunderstorms cannot be ruled out, especially in the strongest areas.

According to global model guidance, a change in the wind pattern is expected on Tuesday due to the According to global model guidance, a change in the wind pattern is expected on Tuesday due to the combined influence of a surface high-pressure system building over the central Atlantic and the passage of a weak surface perturbation across the region. Under this evolving pattern, low-level winds will remain from the northeast during the morning hours before gradually veering to an easterly component around midday. During the day, the GFS indicates precipitable water values fluctuating between 1.4 and 1.6 inches, near to slightly above climatological normals, supporting a high potential for shower development across the islands. Morning shower activity will primarily affect northeastern Puerto Rico and the U.S. Virgin Islands, followed by the development of afternoon convection along the Cordillera Central and into the western interior, aided by local effects and diurnal heating. During the nighttime hours, the available moisture may enhance additional shower activity across the local waters and adjacent coastal areas. By Wednesday, a similar pattern is expected to persist under the continued influence of the surface high, with easterly winds gradually becoming more southeasterly by the afternoon, promoting a warmer temperatures.

Long Term(Thursday through Monday)

Issued at 309 AM AST Mon Mar 23 2026

Moisture is expected to remain elevated from Thursday through the weekend, with precipitable water (PW) values generally in the 1.50 to 1.80 inch range or above normal values for late March. Increased low and mid-level moisture, along with a weak mid- to upper-level trough moving through the region and weak surface perturbations, will support frequent periods of cloudiness and showers. Temperatures near 500 mb are forecast to remain around 6 to 8 degrees C, indicating moderate instability. This environment may support periods of moderate to heavy showers, particularly on Friday. Regardless, widespread organized convection is not anticipated. Enhanced cloud cover should limit daytime heating, keeping high temperatures near typical seasonal values. Winds are expected to gradually increase to 15 to 20 knots, with locally gusty conditions in and near shower activity.

Over the weekend, unsettled conditions are expected to persist as moisture remains elevated and weak disturbances remain near the region. This will result in continued periods of showers or simply increased cloud cover. Overall weather conditions will remain wet and somewhat variable.

Conditions are expected to gradually improve during the upcoming workweek as a drier airmass filters into the area. Shower coverage should decrease, while temperatures remain near seasonal norms.

AVIATION

(06Z TAFS) Issued at 309 AM AST Mon Mar 23 2026

VFR conditions are expected to prevail across all TAF sites throughout the forecast period. Brief MVFR conditions are possible, particularly at TJPS between 23/18Z and 23/21Z, due to reduced VIS and lower CIGs associated with localized convection over the interior and mountainous areas. Low-level winds will remain from the E-NE at less than 8 knots early, increasing to around 15 knots after 23/15Z . Winds will then diminish after 23/23Z, becoming light overnight. Overall, conditions will remain favorable for aviation operations, except for brief, localized impacts from afternoon convection.

MARINE

Issued at 309 AM AST Mon Mar 23 2026

Some influence of a frontal boundary lingering near the region and a surface high pressure over the western Atlantic will continue to promote unsettled marine conditions today, with lingering showers and a slight chance of thunderstorms across the local waters. A fading long- period northerly swell will maintain hazardous seas across the Atlantic waters through this evening. However, moderate to locally fresh north- northeasterly winds will produce choppy seas, particularly across the Mona Passage and offshore Atlantic waters. A surface high pressure building from the western to central Atlantic will maintain northeasterly winds through the first part of the week, with increasing winds and seas expected by midweek.

BEACH FORECAST

Issued at 309 AM AST Mon Mar 23 2026

Life-threatening rip currents are expected along the north-facing beaches of Puerto Rico, from Aguadilla to Fajardo, through this afternoon 6 PM AST, with a High Risk of rip currents. A moderate risk is in effect for Vieques, Culebra, and the U.S. Virgin Islands. Beachgoers should stay cautious, remain near lifeguards, and avoid the water if unsure about conditions.

Looking ahead, an increase in winds around the middle of the week will broaden the rip current risk across most beaches in Puerto Rico and the U.S. Virgin Islands, potentially leading to more widespread hazardous marine and coastal conditions.For more information and specific rip current details, please visit:https://www.weather.gov/beach/sju

SJU WATCHES/WARNINGS/ADVISORIES

PR...High Rip Current Risk through this afternoon for PRZ001-002-005- 008.

High Rip Current Risk until 6 AM AST early this morning for PRZ010.

VI...None. AM...Small Craft Advisory until 6 PM AST this evening for AMZ711.