textproduct: San Juan

KEY MESSAGES

Issued at 100 PM AST Fri Jan 30 2026

* Flood risk increases from Saturday into early next week, with urban and small stream flooding possible and isolated flash flooding where heavy rain persists.

* Marine and beach hazards are possible at times through the weekend, with moderate rip current risk through Saturday and locally high risk possible Saturday night. Dangerous to life- threatening marine and surf zone conditions are expected to return Monday into midweek due to a long-period northerly swell, along with high surf and minor coastal flooding possible.

* Breezy to locally windy conditions late tonight into Saturday may cause localized wind-related hazards, especially across exposed coastal areas of the U.S. Virgin Islands and eastern Puerto Rico.

* Isolated thunderstorms are possible from the weekend into early next week, bringing localized lightning and brief gusty winds.

Short Term(This evening through Sunday)

Issued at 100 PM AST Fri Jan 30 2026

A weak trough moved across the region today, bringing a patch of moisture that produced isolated to scattered showers, mainly across eastern Puerto Rico, the U.S. Virgin Islands, and the local islands, with activity dissipating by late morning. Rainfall totals were generally around one quarter of an inch across eastern Puerto Rico, with lesser amounts elsewhere. Thereafter, daytime heating and local effects led to increased cloudiness across Puerto Rico and showers developing downwind of the local islands. Minimum temperatures were cooler than recent days, dropping into the mid-50s across higher elevations and the mid-60s along coastal areas, while maximum temperatures reached the mid-80s across Puerto Rico and the mid to upper 80s to near 90 across the U.S. Virgin Islands and local islands. Winds were generally easterly, with sea-breeze variations and sustained speeds around 1216 mph, along with occasional higher gusts.

Tonight, the trough will continue lifting northeast, allowing near-normal moisture and typical trade-wind showers to persist overnight, mainly across windward areas and surrounding waters. Moderate southeasterly trade winds will strengthen, becoming locally fresh, and will help advect a wetter-than-normal airmass from the southeastern Caribbean. By late tonight, precipitable water values are expected to increase to well above normal, supporting more frequent showers, mainly over the local waters, with activity moving inland across southern and eastern Puerto Rico, the U.S. Virgin Islands, and nearby islands. Flood risk tonight remains limited and localized, mainly where showers persist or repeat. Strengthening winds may lead to minor wind- related hazards, particularly across more exposed areas of the U.S. Virgin Islands and the local islands. Overnight lows will be warmer than previous nights, remaining in the lower 60s across higher elevations, the mid-70s across coastal and lower elevations, and the upper 70s in more exposed coastal areas.

From Saturday into Sunday, a moisture-rich environment is expected to persist as the region remains positioned between weather features to the west and a ridge to the east, favoring a moisture- trapping pattern. This setup will support periods of scattered to numerous showers, with a few isolated thunderstorms possible given marginal instability. Winds may be breezy at times on Saturday, posing a limited wind-related hazard risk, especially across exposed coastal areas and higher elevations, then weaken and become more variable late Saturday into Sunday, which may allow for slower-moving showers. As a result, flood risk is expected to range from limited to elevated, with urban and small stream flooding possible and isolated flash flooding where rainfall persists or repeats. Maximum temperatures are expected to be near normal on Saturday, with slightly warmer conditions possible on Sunday, while overnight lows remain fairly uniform due to persistent cloud cover.

Long Term(Monday through next Thursday)

Issued at 100 PM AST Fri Jan 30 2026

An unsettled and wet pattern will persist through the long-term period as a frontal boundary approaches the region. This boundary, combined with tropical moisture drawn from South America and the Caribbean, will enhance instability and rainfall potential through the end of the workweek. Recent global model runs suggest precipitable water values will remain well above seasonal climatological norms, ranging between 2.00 and 2.25 inches for most of the period.

At the upper levels, the forecast remains on track. An upper- level trough is positioned over the western Atlantic, while a ridge stays to the east-southeast of the local area through late Tuesday night into early Wednesday. Under this scenario, the combination of upper-level dynamics and persistent low-level moisture convergence along the frontal boundary will support widespread rainfall and the possibility of thunderstorms starting Monday.

As the front moves closer, winds will shift from a south- southwest component to a north-northeasterly flow by Monday night. This pattern will persist through at least Thursday, at which point winds will become more easterly as the frontal boundary begins to exit the region.

The latest model guidance continues to suggest a wet start to the workweek, with Monday and Tuesday expected to be the most active days. This activity is driven by the frontal passage and moisture influx from the Caribbean, combined with daytime heating and local orographic effects. Currently, there is an elevated flooding potential across portions of northern and western Puerto Rico on Monday, shifting to eastern and southern Puerto Rico, Culebra, and Vieques by Tuesday. For the U.S. Virgin Islands, the risk remains limited at this time.

Residents and visitors should closely monitor weather conditions next week, particularly if planning outdoor activities. Stay informed!

AVIATION

(18Z TAFs) Issued at 100 PM AST Fri Jan 30 2026

Mainly VFR early. Diurnal heating/local effects may bring SHRA near TJSJ/TJBQ this aftn. Incr mstr and llvl cnvg will lead to more freq SHRA late tngt into Sat, affecting TJPS, TJSJ, and USVI TAF sites, with brief MVFR and minor ops impacts psbl aft 31/10Z. Isold TSRA psbl as activity spreads acrs the area aft 31/10Z. Aft 31/16Z, SHRA may affect most/all TAF sites. ESE winds 1015 kt with sea-breeze vrblty and ocnl higher gusts near SHRA, weakening ovrngt, then incr again Sat with sust winds arnd 1418 kt.

MARINE

Issued at 100 PM AST Fri Jan 30 2026

Moderate east to southeasterly winds will continue to veer to the southeast and strengthen to locally fresh late tonight into Saturday. These strengthening winds will lead to hazardous conditions for small craft, particularly across the Atlantic waters, where Small Craft Advisories are expected to go into effect Saturday morning. Winds are forecast to gradually ease late Saturday into Sunday; however, a long-period northerly swell is expected to arrive, building seas to around 10 feet late Sunday into midweek. In addition, an unsettled weather pattern will bring more frequent showers and a few isolated thunderstorms, which could locally create hazardous marine conditions or exacerbate existing hazards.

SJU WATCHES/WARNINGS/ADVISORIES

PR...High Rip Current Risk until 6 PM AST this evening for PRZ001-002- 005-008-010-012.

VI...High Rip Current Risk until 6 PM AST this evening for VIZ001.

AM...Small Craft Advisory from 6 AM Saturday to 6 AM AST Sunday for AMZ711.