textproduct: San Juan

KEY MESSAGES

Issued at 155 PM AST Thu May 14 2026

* A warming trend is forecast from tomorrow into Saturday across the islands, with heat index values expected to range between 100 and 108 degrees.

* Improving coastal conditions are expected tonight into Friday across most coastal areas as the northeasterly swell gradually subsides, although a moderate risk of rip currents will continue for several local beaches.

* A more unsettled weather pattern is forecast from Friday into Sunday as an upper-level trough sinks closer to the forecast area, increasing the potential for showers and isolated thunderstorms across portions of the islands.

* In addition, particles associated with Saharan dust are expected to reach the local islands from Friday into Saturday, potentially affecting air quality and causing reduced visibility, especially for individuals with allergies or asthma.

Short Term(This evening through Saturday)

Issued at 155 PM AST Thu May 14 2026

Variable weather conditions prevailed throughout the morning as a patch of moisture moved into the region, bringing fast-moving showers steered by the trade winds. Doppler radar and satellite imagery showed these showers affecting primarily southern, eastern, and central Puerto Rico, with rainfall accumulations ranging from 0.30 to 0.75 inches. Maximum temperatures reached the upper 80s to low 90s across coastal and urban areas, while the central mountain range saw temperatures between the upper 70s and mid-80s. Winds remained out of the southeast at 15 to 20 mph, with higher gusts and sea breeze variations. Although a Heat Advisory was in effect today for coastal and urban areas, heat indices remained between 100 and 105F, slightly below the advisory threshold due to persistent cloud cover.

For the remainder of the day, shower coverage will increase across the interior and northern-northwestern Puerto Rico, driven by daytime heating and local effects. However, these showers are expected to move quickly, resulting in minimal accumulations. Across the U.S. Virgin Islands, streamer activity will develop and move offshore over the Anegada Passage.

For the rest of the period, mainly fair weather is anticipated to prevail under east-southeasterly winds, influenced by a surface high- pressure system in the central Atlantic. Occasional patches of moisture will continue to be dragged into the area, promoting periods of showery weather, especially during the overnight and morning hours. During the afternoon, local effects, low-level convergence, and terrain influences may enhance rainfall, leading to periods of moderate to locally heavy rain across the interior and northwestern Puerto Rico. Consequently, ponding on roads, reduced visibility, and isolated urban or small-stream flooding will remain possible through Saturday.

By late Friday into Saturday, traces of Saharan dust will reach the northeastern Caribbean. Current model guidance suggests the highest concentrations will stay further south over the Caribbean Sea, limiting the impact on the local islands; however, hazy skies and minor reductions in air quality and visibility remain possible. Warm to hot temperatures will persist through next week, potentially leading to elevated heat indices across urban and coastal areas. This heat could pose a risk to sensitive individuals. Residents and visitors are urged to stay hydrated, seek shade, and monitor local conditions to ensure safety during peak temperature hours.

Long Term(Sunday through next Wednesday)

Issued at 155 PM AST Thu May 14 2026

The inherited forecast remains on track, with Sunday expected to be the driest and most stable day of the long-term period. Residual concentrations of Saharan Air Layer (SAL) dust will linger mainly south of the islands through Sunday, according to the latest Dust model guidance. Although relatively drier and more stable conditions are anticipated, available low-level moisture and local effects will still promote periods of passing showers, particularly during the overnight and morning hours across eastern Puerto Rico and the U.S. Virgin Islands. Afternoon shallow convection is expected across western Puerto Rico.

Beginning Monday, moisture and instability will gradually increase across the region as an upper-level trough amplifies over the northeastern Caribbean and potentially evolves into a cut-off low near the Bahamas by midweek. Latest model guidance indicates 250 mb heights gradually lowering starting Monday, while 500 mb temperatures cool to around -7 to -8 degrees Celsius from Tuesday through Thursday. At the same time, precipitable water (PWAT) values are forecast to remain near climatological normals initially before gradually increasing. As deeper tropical moisture spreads across the islands during the first half of the workweek, shower coverage and frequency are expected to increase. By Wednesday and beyond, the combination of higher moisture content and cooler temperatures aloft will support the most unstable conditions of the forecast period. This pattern will favor more organized afternoon convection with isolated to scattered thunderstorms across western and northwestern Puerto Rico, with activity potentially extending into portions of the San Juan Metropolitan Area. Periods of locally heavy rainfall may result in minor urban and small-stream flooding, particularly in windward and urban areas. Overall, active weather is anticipated during the afternoon hours through much of the long-term forecast period.

Temperatures are expected to remain warm throughout the period as southeasterly winds persist across the region. Combined with increasing moisture, heat indices will likely exceed 100 degrees Fahrenheit across lower elevations and urban areas, resulting in a limited to locally elevated heat risk each day. Residents and visitors should continue to monitor future forecasts, as Heat Advisory issuances may become necessary.

AVIATION

(18Z TAFS) Issued at 155 PM AST Thu May 14 2026

FR conditions are expected to prevail across all TAF sites through the period. VCSH to SHRA will continue across the local islands this afternoon and may result in reduced VIS and lower CIGs, mainly near TJMZ and TJBQ. Mountain obscurations will remain possible near the strongest showers. Winds will continue from the E-SE at 15 kt or less with occasional gusts near SHRA activity. After 14/23Z, winds are forecast to gradually diminish, becoming light from the E-SE overnight.

MARINE

Issued at 155 PM AST Thu May 14 2026

Marine conditions across the regional waters will be driven by a broad surface high-pressure system located over the Central Atlantic, maintaining a moderate to locally fresh east-to- southeasterly wind flow through at least the weekend. Under this prevailing pattern, seas are expected to remain generally between 3 and 5 feet across most local waters, resulting in choppy conditions at times, particularly across the offshore Atlantic waters and local passages. Similar marine conditions are expected to persist through Sunday.

However, by Monday, model guidance suggests a slight increase in wind speeds and a corresponding increase in wind- driven seas. As a result, seas could build up to around 6 feet across portions of the northeastern offshore waters and local passages, while winds may increase up to 20 knots at times. Although hazardous marine conditions are not expected to become widespread at this time, small craft operators should continue to exercise caution, especially across exposed Atlantic waters and passages where choppy seas and locally higher wave conditions may develop early next week.

BEACH FORECAST

Issued at 155 PM AST Thu May 14 2026

Breezy east to east-southeasterly winds will continue across the regional waters through at least today, maintaining hazardous marine and surf conditions across many local beaches, particularly along the north and east-facing coastlines through early this evening. These conditions, combined with a lingering northeasterly swell and locally generated wind waves, will continue to support life-threatening rip currents across the surf zone. However, marine and coastal conditions are expected to gradually improve tonight into early Friday as the northeasterly swell slowly subsides, allowing the rip current risk to transition from high to moderate across several beaches. Although conditions should remain favorable for beachgoers, persons should continue exercising caution due to the continued risk of dangerous rip currents.

SJU WATCHES/WARNINGS/ADVISORIES

PR...High Rip Current Risk through late tonight for PRZ001-002-005- 008-012.

Heat Advisory until 4 PM AST this afternoon for PRZ001>003-005- 007-008-010>013.

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

Heat Advisory until 4 PM AST this afternoon for VIZ001-002.

AM...None.