textproduct: San Juan

KEY MESSAGES

Issued at 149 PM AST Wed Nov 11 2026

* Hot and humid conditions will persist through Friday, especially across coastal and lower elevations in the US Virgin Islands and Puerto Rico. A Heat Advisory may be needed as conditions evolve.

* Isolated to scattered showers will favor northwestern Puerto Rico this afternoon, with brief heavy downpours possible. Significant rainfall potential remains low, and most activity should diminish shortly after sunset.

* A modest increase in passing showers is expected Thursday, favoring the USVI and PRs windward areas in the morning and localized afternoon development.

* Generally fair weather will prevail Friday as mid-level high pressure strengthens, limiting rainfall to isolated showers driven by local effects.

* A moderate risk of rip currents will persist at most exposed beaches across Puerto Rico and the U.S. Virgin Islands throughout the forecast period. Life-threatening rip currents are possible. Swim near a lifeguard and follow posted beach warnings.

Short Term(This evening through Friday)

Issued at 149 PM AST Wed Nov 11 2026

Mostly sunny skies and little to no rainfall prevailed across Puerto Rico and the U.S. Virgin Islands this Veterans Day morning. Cloud cover began to increase modestly over the higher terrain by late morning into midday as daytime heating and orographic effects promoted cloud development. Maximum temperatures recorded so far today generally reached the upper 80s to lower 90s across coastal and lower elevations, while higher elevations remained cooler, mostly in the 70s to lower 80s. With sufficient near- surface humidity, these temperatures produced heat indices generally between 100 and 107 degrees, with a few stations reporting values above 107 degrees. Winds were generally east to southeast at 5 to 15 mph, with locally lighter winds inland and occasional higher gusts along coastal areas.

A mid- to upper-level ridge near the region will maintain subsidence and dry air aloft, favoring generally fair weather across most of Puerto Rico and the U.S. Virgin Islands through early Thursday. However, daytime heating, sea breeze convergence, and local terrain effects could locally overcome this suppression, supporting isolated to scattered showers across northwestern Puerto Rico this afternoon. Brief, locally heavy downpours remain possible, although the potential for significant rainfall is low. Most activity should diminish shortly after sunset as daytime heating wanes. A few streamer showers may also develop downwind of the U.S. Virgin Islands this afternoon. Otherwise, conditions should remain mostly dry overnight into early Thursday, with only isolated passing showers. Hot, humid conditions will persist through the rest of the afternoon, especially along the coast and at lower elevations, with temperatures gradually easing this evening.

On Thursday, a passing shortwave trough will modestly weaken the mid- to upper-level ridge, allowing a slight increase in moisture depth and a modest uptick in shower activity. Passing showers will favor windward areas during the morning, followed by additional afternoon development driven by daytime heating, sea breeze convergence, and terrain effects. Nevertheless, limited moisture and lingering stability should keep rainfall localized. Hot and humid conditions will persist, and a Heat Advisory may be necessary if forecast heat indices and their duration warrant it; we will reassess this potential in subsequent forecasts. By Friday, mid-level high pressure will reestablish itself, reinforcing subsidence and limiting shower coverage and vertical development. Overall, a relatively stable pattern will prevail, with local effects driving isolated afternoon showers and most areas experiencing extended dry periods.

Long Term(Saturday through Wednesday)

Issued at 306 AM AST Wed Nov 11 2026

The forecast remains predominantly on track. Model guidance indicates that a surface high pressure over the east-to-central Atlantic will maintain a calm-to-breezy SSE to SE wind flow across the islands through Sunday. As the high pressure recedes further into the eastern Atlantic Ocean the winds will shift to be calm and from the ENE on Monday. On Tuesday a developing surface low- pressure system to the NW of the islands will again shift the direction of the winds to be predominantly from the ESE. Available moisture will reduce into the long-term period across the CWA as precipitable water (PWAT) and column relative humidity values remain below seasonal levels acting as a limiting factor for the development of convection. Another inhibiting factor for the development of deep convective cells will be a mid-level ridge over the eastern Caribbean. This high-pressure will warm temperatures above -6 degrees Celsius (probability of exceedance of around 70% each day) and consequently weaken the lapse rates at these levels. These conditions will lead to subsidence and stability above. Nonetheless, available moisture along with local effects (i.e., sea-breeze convergence, orographic effects and diurnal heating) will lead to the development of showers and thunderstorms each afternoon with a focus along the northern interior, western interior, and northwestern regions of Puerto Rico during the afternoons. Advective showers during the mornings and nights and streamers from El Yunque and the smaller islands during the afternoons will impact portions of the US Virgin Islands and eastern Puerto Rico each day.

Some of the expected risks throughout the long-term include ponding of water in roads and poorly drained areas as well as a a low chance of urban and small streams flooding over region where frequent downpours occur. One of the main concerns for the long-term forecast are associated to heat. The available moisture, calm winds, and lower cloud cover and above seasonal 925 mb temperatures will lead to a level of heat that affects most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration.

AVIATION

(18Z TAFS) Issued at 149 PM AST Wed Nov 11 2026

All TAF site should experience VFR conditions through the period. However, brief periods of MVFR conds are possible near TJBQ with VCTS and -SHRA. SE winds should prevail around 10 to 15kt but occasionally higher gust near the RA and TS activity through 11/22Z. Decreasing winds around 5 kts after 11/23Z, before picking up again after 12/13Z to up to around 8 to 13 kts from the SE with sea breeze variations and local effects.

MARINE

Issued at 149 PM AST Wed Nov 11 2026

Surface high pressure strengthening over the central Atlantic will tighten the local pressure gradient, increasing east-to-southeast winds through the latter part of the week. Winds of 10 to 15 knots will increase to 15 to 20 knots Thursday night into Friday, with locally higher gusts. Although the northerly swell will gradually diminish, increasing wind-driven seas will maintain combined seas generally between 4 and 5 feet across offshore waters, occasionally reaching 6 feet. Small craft should exercise caution across exposed waters and local passages, particularly Thursday night through Saturday. Isolated to scattered showers are expected, with a modest increase Thursday as a shortwave trough passes nearby. Winds and seas should gradually subside later this weekend.

BEACH FORECAST

Issued at 149 PM AST Wed Nov 11 2026

A moderate risk of life-threatening rip currents will prevail the rest of today along the north- and east-facing beaches of Puerto Rico, Culebra, Vieques, and the U.S. Virgin Islands. The moderate risk will turn widespread across most of the expose beaches in the USVI and PR, as the trade winds strengthen.

Beachgoers should remain cautious, as life-threatening rip currents are possible in the surf zone.

Regardless of the slight chance for thunderstorm development, lightning activity pose another beach hazard, particularly during the afternoon hours. If thunder is heard, seek shelter immediately.

SJU WATCHES/WARNINGS/ADVISORIES

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