textproduct: San Juan

KEY MESSAGES

Updated at 410 AM AST Sun May 3 2026

* A few brief afternoon showers are possible over western Puerto Rico today, with mostly fair weather expected overall.

* Increasingly stable conditions will lead to generally fair weather into early this week.

* Warmer-than-normal temperatures will persist, with heat indices reaching or exceeding 100F across urban and coastal areas.

* A moderate risk of rip currents will continue along north- and east-facing beaches of Puerto Rico and the U.S. Virgin Islands.

Short Term(Today through Tuesday)

Issued at 410 AM AST Sun May 3 2026

A gradual transition toward a somewhat more stable weather pattern will continue through the period. PWAT values will fluctuate between near normal and below normal, generally ranging from about 1.3 to 1.6 inches, while mid-level relative humidity (700-500 mb) remains limited, around 30 to 45 percent. Although 500 mb temperatures near -9C to -7C and above normal 700-500 mb lapse rates indicate sufficient instability aloft, the primary limiting factor will be the available moisture content, resulting in mostly shallow convective activity.

For today, expect mostly clear to partly cloudy skies during the morning hours, followed by isolated to scattered afternoon showers over the interior and northwestern Puerto Rico, driven by diurnal heating and sea breeze convergence. Passing trade wind showers will continue across windward areas and the U.S. Virgin Islands during the overnight and early morning hours.

On Monday, continued modest drying aloft and PWAT values near to below normal will promote reduced coverage and intensity of showers, although isolated afternoon activity will still develop over western Puerto Rico. Model guidance suggests a modest surge of moisture by Tuesday morning, which could result in a temporary increase in trade wind showers, mainly across windward areas. Otherwise, mostly fair weather conditions will prevail.

Southeasterly wind flow will continue to advect warmer-than-normal temperatures, supported by above-normal 925 mb temperatures indicated by model guidance, resulting in highs in the upper 80s to low 90s and heat indices likely exceeding 100F across coastal and urban areas.

Long Term(Wednesday through Sunday)

Issued at 410 AM AST Sun May 3 2026

An upper level trough will cross the local islands on Wednesday, causing mid-levels temperature to cool down. Although this would usually result in an increase in instability, a mid-level ridge will maintain conditions generally unfavorable for strong showers production. Later in the workweek, a cold front at the mid-levels will cross the region. The air mass will dry out further, with the forecast soundings suggesting considerable dew point depressions and trade wind caps around 850 mb levels. In general, fair weather will prevail, but diurnal heating should still trigger localized convection in the interior and west of Puerto Rico. Also, patches of moisture trapped in the lower 850 mb of the atmosphere will be dragged by the trade winds along the Virgin Islands and eastern Puerto Rico at times. However, the risk of flooding will be low to none for most of the period.

The steering flow at the surface will be mainly out of the east at around 10 knots through much of the forecast period. Aloft, winds will be from the north, but this will not translate into cooler temperatures. Highs will still reach the upper 80s and low 90s along many coastal areas, and around 80 in the mountain.

In comparison with the previous cycles, the probability of precipitation has been decreased for most of the period. By the next weekend however, the mid level ridge will lose its grip a little, as a mid to upper level low develops northeast of the Caribbean. Stronger showers and isolated thunderstorms are expected to form, mostly focusing along the interior and western Puerto Rico.

AVIATION

(06Z TAFS) Issued at 410 AM AST Sun May 3 2026

VFR conds expected thru the fcst pd. FEW-SCT clouds at or above FL025-FL030 with limited SHRA activity. Iso VCSH psbl mainly btw 17-22Z across W PR terminals (TJBQ). SFC winds light/vrb ovrngt bcmg E-SE 10-15 kt aft 13-14Z with sea breeze variations and ocnl gusts up to 20 kt. The 03/00Z sndg shows winds up to 19 kt blo FL050. No sig aviation impacts expected.

MARINE

Issued at 410 AM AST Sun May 3 2026

A broad high pressure over the central Atlantic will promote gentle to moderate east to east-southeast winds across most waters through early this workweek. Moderate to locally fresh winds are expected across the local Caribbean passages today and tomorrow, where small craft operators should exercise caution. Seas will range between 3 and 5 feet, occasionally reaching up to 6 feet, due to local wind waves and a small, long-period northeasterly swell. Passing showers at times across the waters.

BEACH FORECAST

Issued at 410 AM AST Sun May 3 2026

Up to a moderate risk of rip currents (life-threatening rip currents are possible in the surf zone) will continue today for the north and east beaches of Puerto Rico, as well as exposed beaches of Culebra and the USVI. A low risk of rip currents will continue elsewhere. However, even if the risk for rip currents is low, life-threatening rip currents often occur in the vicinity of groins, jetties, reefs, and piers. This pattern will continue at least through Wednesday, as pulses of a small, long-period northeasterly swell reach the area. For the second half of the week, the low risk of rip currents will be more dominant.

For additional information, visit: weather.gov/beach/sju.

SJU WATCHES/WARNINGS/ADVISORIES

PR...None. VI...None. AM...None.