textproduct: San Juan

KEY MESSAGES

Issued at 352 AM AST Fri Jan 16 2026

* Quiet morning today with a few trade wind showers and increase rainfall activity by the afternoon hours along the west resulting in wet pavement and low- lying flooding.

* A strengthening to a moderate breeze is forecast by Friday afternoon into the weekend. Please secure outside objects.

* An increase in rip current risk is forecast for the northern, exposed beaches.

Short Term(Today through Sunday)

Issued at 352 AM AST Fri Jan 16 2026

Overall conditions were warmer than normal, with slightly cooler temperatures across windward areas, where passing showers were observed overnight. Skies remained variably cloudy, dominated by mid- to upper-level cloud cover. Shower activity was limited, with no significant rainfall accumulations reported. Winds were generally from the east-southeast, remaining light to calm and variable over land.

Today, conditions start relatively quiet this morning, with a few trade-wind showers over windward areas, then transition as east- southeasterly winds and daytime heating take hold. Warmer-than- normal temperatures are expected, with highs reaching the upper 80s across lower elevations of northern and western Puerto Rico. By the afternoon, scattered to locally numerous showers will develop mainly across western to southwestern Puerto Rico, with a chance of isolated thunderstorms. Impacts should remain limited, with brief ponding and localized minor flooding possible in western Puerto Rico, along with a low lightning risk.

From tonight through Sunday, low-level winds will strengthen as a building surface high over the North Atlantic tightens the pressure gradient across the region, with passing easterly (trade-wind) disturbances modulating conditions. Winds will back to east- northeasterly tonight, then veer back to easterly on Saturday and Sunday, supporting a gradual cooling trend. The first and most prominent disturbance will bring a wetter band early Saturday to the U.S. Virgin Islands, Culebra, Vieques, and eastern Puerto Rico, followed by afternoon shower development across western Puerto Rico. From Saturday night through Sunday, a trade-wind-driven pattern persists with fresh to locally strong winds and passing showers, while conditions become more stable by Sunday afternoon; overall hazards include localized ponding and minor flooding mainly Saturday across northeastern and western Puerto Rico, and increasing wind impacts beginning tonight and persisting through the weekend, especially across exposed and coastal areas.

Long Term(Monday through Friday)

Issued at 352 AM AST Fri Jan 16 2026

The latest model guidance indicates a transition toward a wetter and more unsettled pattern beginning Monday and continuing through much of the workweek. Precipitable water values are forecast to increase to around 1.75 inches, which is above normal for this time of year and supportive of additional rainfall activity, particularly by midweek. From Monday through Wednesday, a subtropical jet streak near 250 mb will enhance upper-level divergence and support the development of an induced surface trough, resulting in higher shower coverage across the forecast area as easterly to northeasterly low-level flow becomes established by midweek.

Tuesday may see some variability as guidance hints at a pocket of drier air moving south of the region. At this time, it remains unclear whether this drier air will reach the forecast area, and its potential influence on rainfall will continue to be monitored.

Wednesday currently appears to be the wettest and most unstable day of the long-term period. 500 mb temperatures near -7 degrees Celsius will promote greater vertical growth of convection, increasing instability and the potential for isolated thunderstorms, particularly during the afternoon hours. In addition, weakening low-level winds may allow showers to persist over the same areas for extended periods, potentially elevating the risk of localized flooding.

From Monday onward, 925 mb temperatures are expected to remain above normal. When combined with the increasing moisture, conditions may feel warmer than they actually are. While rainfall coverage and intensity may vary at times, each afternoon carries at least a limited flooding risk, primarily due to ponding of water on roads and in poorly drained locations.

AVIATION

(06Z TAFS) Issued at 352 AM AST Fri Jan 16 2026

Mainly VFR expd across all TAF sites thru the fcst pd. Psg TW SHRA may affect TJSJ & USVI terminals at times, with brief MVFR vsby/cigs psbl in heavier SHRA. Aftn SHRA w/ iso TSRA may impact TJBQ (16/1722Z), again with brief MVFR psbl. Activity diminishes aft sunset. Sfc winds lgt/vrb early, bcmg ESE 1015 kt w/ aftn gusts, then around 812 kt aft 16/22Z. No sig or prolonged avn impacts expd.

MARINE

Issued at 352 AM AST Fri Jan 16 2026

Surface winds continue from the southeast through later today. On Saturday, strengthening east to northeast winds, and the arrival of a long- period northerly swell will likely result in choppy to rough seas, leading to hazardous marine conditions during the weekend into the upcoming workweek. A Small Craft Advisory will be in effect for the Offshore Atlantic waters from late Saturday into Monday. Mariners are urge to exercise caution across the offshore Atlantic waters and the local passages as we head into the weekend.

BEACH FORECAST

Issued at 352 AM AST Fri Jan 16 2026

The moderate risk of rip currents along all the northern-exposed beaches in Puerto Rico and the U.S. Virgin Islands will remain favorable through Friday. Conditions will deteriorate Saturday and Sunday, when energy from a northerly swell moves in and winds increase, resulting in breaking waves along all the north and northeast coasts of Puerto Rico, including Culebra. As a result, a high risk of rip current is forecast for the upcoming weekend.

SJU WATCHES/WARNINGS/ADVISORIES

PR...None. VI...None. AM...Small Craft Advisory from 2 PM Saturday to 2 PM AST Monday for AMZ711.