textproduct: San Juan

KEY MESSAGES

Issued at 132 AM AST Thu Mar 19 2026

* Hazardous seas and life-threatening rip currents continue across the Atlantic waters, and along the north and eastern beaches of the islands.

* Fair weather conditions and warmer than normal temperatures are expected across the U.S. Virgin Islands today. Similar conditions are expected for Puerto Rico, with showers developing over the NW sections this afternoon.

* A frontal boundary and associated trough will increase shower activity from late this week into the weekend, bringing periods of unsettled weather across Puerto Rico and the U.S. Virgin Islands.

Short Term(Today through Saturday)

Issued at 132 AM AST Thu Mar 19 2026

Mostly clear to partly cloudy skies were observed across the islands during the night. Passing showers were noted mainly across the eastern and southern portions of Puerto Rico. Minimum temperatures were from the mid-70s across the coastal areas of the islands to the lower 60s in the higher elevations of Puerto Rico. The wind was from the east around 10 mph, with land breeze variations.

Current model guidance suggest that the region will remain under the influence of an upper level ridge, providing warmer 500 mb temperatures (stable conditions aloft), and moderate to light southeasterly trade winds, that will bring periods of dry/moist air through Friday. Therefore, similar conditions are expected today and tomorrow, with passing showers prevailing across windward areas during the night/morning hours, followed by afternoon showers developing over portions of north-northwest PR. A limited flood risk is expected with this activity as localized rainfall accumulations are expected to remain under an inch.

A weather pattern change is expected from late Friday into Saturday. Latest Total Precipitable Water imagery highlights a deep moisture plume trailing a boundary to the northwest over the western Atlantic and the Bahamas, which global models are gradually edging closer to the region by the end of the workweek. Forecast soundings show a sharp increase in moisture profiles by Saturday. PWAT values are forecast to surge above the 75th percentile (reaching up to 1.75 inches), accompanied by significant spikes in both the 850-700mb and 700-500mb relative humidity layers. In addition, lighter steering winds are expected as the frontal boundary moves closer to the region, with 925 mb wind speeds decreasing substantially from 15-20 knots today, down to 5-10 knots over the weekend. This combination of pooling moisture and a weak steering flow will result in increased shower coverage. Therefore, a wetter start to the weekend is expected.

Long Term(Sunday through Thursday)

Issued at 132 AM AST Thu Mar 19 2026

A mid level trough will cross the region on Sunday, while most of its energy remains north of the area, supporting stronger winds aloft and unstable conditions. A pre frontal trough over the area early in the period will promote light and variable winds, becoming calm at times. Behind it, surface high pressure building over the western Atlantic will bring a gradual shift to north easterly winds through midweek. Another mid level trough and associated frontal boundary will approach late Wednesday into Thursday. Moisture will increase from near normal early in the period to above normal by Tuesday onward, with deep moisture in place through the rest of the forecast. Mid level temperatures will remain near normal with occasional cooling aloft, while increased cloud cover and north easterly winds will support a gradual cooling trend.

Unsettled weather conditions will persist with elevated risk of excessive rainfall and thunderstorms each day. Slow moving showers early in the period will increase the risk of flooding in urban areas and small streams. As north easterly winds develop, showers will become more frequent across windward areas, with afternoon activity over interior and western Puerto Rico. From Tuesday onward, deeper moisture will support more efficient rainfall, increasing the flooding risk. Thunderstorms may produce lightning and gusty winds. Residents and visitors should remain alert for periods of heavy rain and thunderstorms.

AVIATION

(06Z TAFS) Issued at 132 AM AST Thu Mar 19 2026

Mainly VFR conditions are expected to prevail across all terminals during the next 24 hours. Mostly VCSH expected across the area terminals. Low-level winds ESE at 10-20 kt, with sea breeze variations expected at TJBQ aft 19/14z.

MARINE

Issued at 132 AM AST Thu Mar 19 2026

As a frontal boundary and pre frontal trough approach the region, winds will veer from the east southeast and gradually diminish, with locally higher winds possible today across the Mona Passage. Seas will slowly subside, but choppy to rough conditions will persist across portions of the local waters. A Small Craft Advisory remains in effect for the offshore Atlantic waters through this afternoon, with Small Craft Should Exercise Caution conditions elsewhere. Winds will shift back from the northeast early next week, with marine conditions generally improving, although unsettled weather will persist.

BEACH FORECAST

Issued at 132 AM AST Thu Mar 19 2026

A high risk of rip currents persist along all northern and eastern beaches of Puerto Rico, as well as across Vieques, Culebra, and the U.S. Virgin Islands. These conditions are life threatening, and a High Rip Current Risk remains in effect for these areas. Beachgoers should avoid entering the water in exposed areas.

Conditions will gradually improve as winds and seas diminish. However, a moderate risk of rip currents will persist along north and east facing beaches, meaning dangerous currents will remain possible even as conditions appear calmer. Even when the risk is low, rip currents can still occur near groins, jetties, reefs, and piers. Residents and visitors should continue to monitor the forecast and exercise caution.

SJU WATCHES/WARNINGS/ADVISORIES

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

VI...High Rip Current Risk through this afternoon for VIZ001-002.

AM...Small Craft Advisory until 6 PM AST this evening for AMZ711.