textproduct: San Juan

KEY MESSAGES

Issued at 1148 AM AST Fri Nov 28 2025

* Occasional showers and isolated thunderstorms are expected this afternoon and evening, posing a limited risk of flooding across Puerto Rico and the U.S. Virgin Islands.

* Breezy trade winds will prevail today, becoming windy during the weekend into early next week.

* The north and east-facing beaches in PR and the USVI have a moderate risk of life-threatening rip currents throughout the weekend.

* Pleasant temperatures, with a mix of sunshine and clouds, will prevail across the USVI and PR throughout the forecast period.

Short Term(This afternoon through Sunday)

Issued at 1148 AM AST Fri Nov 28 2025

Frequent showers embedded in the easterlies moved across the windward locations of Puerto Rico and the U.S. Virgin Islands throughout the morning. Ponding of water along roads and in poorly drained areas was observed during this activity. A few thunderstorms were noted by radar and satellite imagery. Afternoon convection developed along the Cordillera Central and western PR, as well as downwind from the USVI. Winds were mainly from the east at 15 to 20 mph, but locally higher near showers and thunderstorms. Maximum temperatures were in the mid-80s or upper 80s along the coast and in urban areas, and in the upper 70s or low 80s in the mountains and valleys.

An upper-level trough is expected to exit the northeast Caribbean today, allowing a mid- to upper-level ridge to likely build over the islands later today and through the weekend. Another upper- level trough has a moderate chance of moving across the region from Sunday into early next week, which would increase instability, particularly Sunday afternoon and evening.

At the surface, the interaction between a surface high pressure system over the central Atlantic and a cold front moving east across the western Atlantic will likely support breezy to windy trade wind conditions through the weekend.

Given this pattern, there is a moderate (30-50%) to high (60%) chance of occasional passing showers across the islands, especially over the windward areas. This afternoon into the evening, showers are expected to spread into the interior and western Puerto Rico, with a moderate (50%) to high (60-80%) chance of rain. There is a slight risk of flooding rains and isolated thunderstorms across portions of the U.S. Virgin Islands and eastern, interior, and western Puerto Rico.

Although conditions are likely to be more stable on Saturday, tradewind showers will continue at times, with a moderate (30-50%) chance. These showers may extend inland and into western Puerto Rico by the afternoon, where the chance of rain is moderate (40-50%) to high (60%).

A similar pattern is likely on Sunday, but with greater instability, increasing the potential for flooding rains and thunderstorms.

Long Term(Monday through next Friday)

Issued at 542 AM AST Fri Nov 28 2025

By early next week, winds will remain somewhat breezy but will gradually subside as a polar trough pushes and weakens the surface high over the northeastern Atlantic, easing the pressure gradient across the region. By Tuesday and Wednesday, expect northeasterly winds with speeds decreasing to around 8 to 13 mph.

According to the latest precipitable water (PWAT) guidance, moisture will vary as patches of drier and slightly more humid air move through the area. From Monday through early Wednesday, PWAT values will remain near normal for this time of year, ranging between 1.50 and 1.75 inches. This streaming moisture will support passing showers, mainly steered by a northeasterly flow, affecting windward sectors at times. Afternoon convection is also possible, especially over interior and southwestern Puerto Rico, where brief heavy downpours may occur.

By Wednesday afternoon, PWAT values will begin increasing, reaching 1.75 to 2.00 inches through Thursday. Model guidance indicates a surface trough approaching the region Wednesday afternoon into Thursday, accompanied by upper-level troughing. This will enhance moisture and instability while causing the steering flow to veer more easterly. As a result, this period have the highest chances of precipitation, though the flood risk remains limited at this time. Continue to monitor forecast updates as confidence improves in the coming days. Winds are also expected to become breezy again from Thursday into Friday. By the end of the period, Friday, more stable conditions are expected as ridging builds at various levels of the atmosphere, introducing drier air with PWAT values falling below 1.4 inches, along with breezy easterly winds.

Temperatures at 925 mb are forecast to rise to near-average values, supporting seasonal surface temperatures. However, no heat-related risks are anticipated at this time.

AVIATION

(18Z TAFS) Issued at 1148 AM AST Fri Nov 28 2025

SHRA/ISOLD TSRA will affect PR/USVI terminals with brief MVFR/IFR in +SHRA/TSRA, and BKN CIGS at FL020040, particularly ovr TJBQ/TJSJ terminals. Outside convective bursts, VFR prevails. E-ESE sfc winds 1318 kt with ocnl G2025 kt and sea-breeze variation. Winds bcm VRB0306KT aft 28/22Z. USVI terminals may also see VCSH/VCTS in streamer bands. Impacts mainly tempo and short-lived.

MARINE

Issued at 1148 AM AST Fri Nov 28 2025

An upper-level trough moving across the Northeast Caribbean will promote thunderstorm formation over local waters, especially during the afternoon and evening hours. A surface high pressure over the Central Atlantic, interacting with a cold front moving eastward across the western Atlantic, will promote moderate to fresh easterlies winds today, becoming fresh to strong trade winds this weekend into early next week. This will result in rough to hazardous seas across the local waters today and throughout the weekend.

BEACH FORECAST

Issued at 1148 AM AST Fri Nov 28 2025

The risk of encountering life-threatening rip currents remains moderate along north- and east-facing beaches from northwestern to eastern Puerto Rico, as well as in Vieques, Culebra, and the U.S. Virgin Islands. This moderate risk will persist through the forecast period, with life-threatening rip currents possible, especially along the north and east-facing beaches of the islands. In other areas, the risk is low; however, even in low-risk areas, dangerous rip currents can still develop near groins, jetties, reefs, and piers.

SJU WATCHES/WARNINGS/ADVISORIES

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