textproduct: San Juan

KEY MESSAGES

Issued at 508 AM AST Wed Jan 21 2026

* Breezy to windy conditions will continue today, which could cause outdoor items to be blown around or damaged.

* Choppy to rough seas will result in hazardous marine and coastal conditions. Small Craft Advisories and High Rip Current Statements will likely remain in effect through the rest of the workweek.

* Fast moving trade wind showers will continue, resulting in slippery road conditions and ponding of water in low-lying and poor drainage areas. Afternoon showers likely to develop over interior to western PR.

* A surface trough moving westward across the region from late tonight into Friday will gradually deteriorate weather conditions, increasing the potential for showers and isolated thunderstorms.

Short Term(Today through Friday)

Issued at 508 AM AST Wed Jan 21 2026

A variable weather pattern prevailed during the night into the early morning hours. Satellite and radar imagery showed patches of cloudiness and frequent passing showers across the local waters, briefly affecting the eastern sections of the main islands and the U.S. Virgin Islands. Around 3:00 AM, a moderate shower moved across the San Juan metropolitan area, tracking westward and affecting northern municipalities. This shower activity was accompanied by gusty winds, according to unofficial weather stations, with gusts reported up to 21 knots. Overnight low temperatures ranged from the mid to upper 70s across coastal areas to the low 60s across the interior.

A broad surface high pressure over the Central Atlantic will be the main weather feature today, resulting in breezy conditions with east winds up to 15 knots. Under this pattern, patches of moisture embedded in the winds will result in cloudiness and frequent showers moving in and out of the region. Since breezy conditions remain, minimal rainfall accumulations are expected from fast-moving showers. Therefore, for the rest of the day, residents and visitors should expect good periods of sunshine across western sections with passing showers across eastern sections of Puerto Rico and the U.S. Virgin Islands. In the afternoon, some brief showers are forecast across some interior areas with no flooding threat.

The weather pattern is forecast to become wetter and marginally unstable from Thursday into Friday as an induced surface trough associated with a cut-off low located well east of the islands moves across the region. According to the latest model guidance, moisture is forecast to increase, with precipitable water values rising from around 1.5 inches on Thursday to near 1.70 inches on Friday, above climatological normals. On Thursday, moisture should remain mostly shallow; however, as the day progresses, 850-500 MB relative humidity values show deep moisture moving into the islands. The presence of abundant moisture will combine with marginally unstable conditions at the mid and upper levels due to a strong jet streak over the area, providing upper divergence, and marginally colder temperatures at 500 MB (-7 to -8 degrees). Given the expected conditions, residents can expect an increase in morning showers, followed by more organized showers across the mountain and western sections. Surface winds will remain breezy; however, with the passage of the induced surface trough, winds are expected to decrease to around 15 knots on Thursday. As a result, residents and visitors can expect showers and isolated thunderstorms, which should bring periods of heavy rainfall and gusty winds, resulting in ponding of water over roadways, urban areas, and poorly drained areas, with minor flooding in these areas. Additionally, reduced visibility and lightning cannot be ruled out. Therefore, for the hazards on Thursday into Friday, a flooding and lightning risk will remain limited.

Long Term(Saturday through Wednesday)

Issued at 508 AM AST Wed Jan 21 2026

Increased moisture and instability will carry from the short term period into Saturday, as the moisture field from the disturbance continues over the region promoting above seasonal precipitable water (PWAT) values (1.50 to near 2 inches). Saturday looks to be the wettest day in the long term period, with advective showers steered by easterly flow and convective afternoon showers over interior to western PR. Improved weather conditions are forecast from late Saturday through Sunday as the atmospheric disturbance and moisture field moves westward and out of the region and drier air advects into the area. Patches of drier and moist air will then promote seasonal (<1.50 in) to below seasonal (<1.20 in) PWAT values over the area. A dominant high-pressure system over the Atlantic will establish a generally more seasonal easterly steering flow, moving advective showers into windward areas, particularly in the morning and overnight hours. Subsidence in the mid-to-upper levels of the atmosphere will inhibit shower development; however, localized effects may still induce convective showers, though no flooding is anticipated. Most available moisture will be limited to below 800 mb. The limited wind risk will gradually subside during the weekend. 925 mb temperatures will remain at seasonal values, overnight patchy fog is also forecast over areas of the interior. Model guidance suggests that variations in this pattern will occur due to an upper trough moving east of the region to start the workweek and a shift in easterly flow on Wednesday to become more northeasterly.

AVIATION

(06Z TAFS) Issued at 508 AM AST Wed Jan 21 2026

VFR conditions will persist across the TAF sites. Winds will persist from the E at 10 knots, increasing up to 15 knots with gusty winds up to 25 knots from 21/14Z lasting during the day. VCSH to SHRA are expected mostly across eastern sites from now through 21/18Z, increasing even more with reduction in VIS and Cigs at 22/03Z as cloudiness and showers from an induced surface trough move across the area.

MARINE

Issued at 508 AM AST Wed Jan 21 2026

A broad surface high pressure over the central Atlantic will continue to strengthen during the next few days, tightening the local pressure gradient and promoting fresh to locally strong easterlies through much of the rest of workweek. This strong surface high pressure will maintain the frontal boundary off to the west of the northeast Caribbean. A surface trough will move across the Northeast Caribbean around Thursday, affecting Puerto Rico and the US Virgin Islands through Saturday.

BEACH FORECAST

Issued at 508 AM AST Wed Jan 21 2026

A high risk of rip currents remains in effect across the northern coasts of Puerto Rico, as well as for Culebra, and the U.S. Virgin Islands, due to hazardous conditions with breaking waves up to 6 to 7 feet. An increase in surface winds from the east will induce choppy seas, resulting in localized hazards. Residents and visitors are urged to continue following the warning flag system and to favor beaches with lower rip current risk, such as those along Puerto Rico's western and southern coasts. Up to a high risk of rip currents is likely to continue through the rest of the workweek.

For the western and southern coastal areas, where the risk remains moderate, beachgoers can expect breezy to locally windy conditions to continue, which may still result in unsecured objects being blown around, particularly in the most exposed locations. Beachgoers should remain cautious both in and near the water until conditions improve further. For localized, up-to-date risk levels, visit: weather.gov/beach/sju.

SJU WATCHES/WARNINGS/ADVISORIES

PR...High Rip Current Risk through Thursday afternoon for PRZ001-002- 005-008-012.

VI...High Rip Current Risk through Thursday afternoon for VIZ001-002.

AM...Small Craft Advisory until 6 PM AST Thursday for AMZ711-712-716- 723-726-733-741.

Small Craft Advisory from midnight tonight to 6 PM AST Thursday for AMZ735.