textproduct: San Juan

KEY MESSAGES

Issued at 415 AM AST Sat Jan 17 2026

* Breezy to windy conditions could lead for unsecured items to be blown around, with outdoor objects potentially displaced in the most exposed locations.

* Deteriorating marine and coastal conditions are expected this weekend as a northerly swell combines with breezy winds, leading to hazardous seas and an increased risk of rip currents, especially along northern and northeast-facing beaches.

* Trade wind showers will continue, with a brief increase in rainfall activity possible during the afternoon hours, mainly across western Puerto Rico, resulting in wet roads and ponding in low-lying and poor drainage areas.

Short Term(Today through Monday)

Issued at 415 AM AST Sat Jan 17 2026

A band of moisture moved into the forecast area overnight, increasing cloudiness and producing isolated to scattered showers, mainly across the northern U.S. Virgin Islands and eastern to northeastern Puerto Rico, with localized rainfall up to around one- half inch. Minimum temperatures were cooler than the previous night, especially across eastern Puerto Rico and southern and western coastal areas, dropping near 60F in higher elevations and into the upper 60s along the southern coast. Winds were generally light and variable, increasing to 1015 mph from the east-northeast with higher gusts as the moisture band passed, consistent with an easterly trade-wind disturbance.

Strengthening ENE to E trade winds today will bring breezy to windy conditions across the region, with gusts occasionally exceeding 30 mph, especially along exposed coasts and higher elevations. Unsecured items may be blown around, with outdoor objects potentially displaced in the most exposed locations. These winds will also push alternating bands of drier and wetter air across the area, leading to periods of cloudiness and fast-moving showers as moisture bands pass. Rainfall will be brief and generally light, though minor ponding in poor drainage areas remains possible, mainly across northeastern Puerto Rico.

Wind-related hazards will be the primary concern over the next few days, with winds peaking tonight into Sunday and breezy to locally windy conditions continuing into early next week, driven by fresh to strong easterly winds. Shower activity will be limited and brief, occurring mainly as shallow, fast-moving trade-wind showers due to dry mid-levels, with minor moisture increases this evening and again Monday evening. No significant flooding is expected, though brief ponding remains possible, mainly across eastern and northeastern Puerto Rico. Outside of passing showers, conditions will generally be tranquil and favorable for outdoor activities, though those planning outdoor activities should remain alert for unsecured items and other wind-related threats, especially in exposed locations.

Long Term(Tuesday through Saturday)

Issued at 415 AM AST Sat Jan 17 2026

Model guidance continues to support a transition toward a wetter and more unsettled pattern beginning Tuesday and persisting through at least Friday, with the most active period expected after Wednesday. Precipitable water values are forecast to increase to above 1.75 inches, which is in the range of above normal values for this time of year and indicative of a deep tropical moisture plume over the region. This moisture, combined with persistently high mid- level relative humidity, will favor frequent shower activity across the islands. Low-level winds are expected to remain generally from the east to northeast and sustained in the 17 to 20 mph range, which should help maintain adequate ventilation while still allowing for periods of locally enhanced rainfall where showers align with terrain or convergence zones. Temperatures are forecast to gradually trend back toward seasonal norms, generally near the 50th percentile for this time of year after midweek.

Tuesday is expected to mark a gradual transition toward a wetter pattern. While a drier air mass is forecast to remain well south of the area, guidance suggests that low concentrations of Saharan air particles may still intermittently filter across the region. Despite this, sufficient low- to mid-level moisture should remain in place to support showers, particularly during the afternoon and evening hours.

The wettest and most unstable portion of the forecast period is expected after Wednesday. While 500 mb temperatures are now forecast to remain closer to normals (around -6 to -7 degrees Celsius), the combination of anomalously high moisture and enhanced low- to mid-level convergence will support thunderstorms. Periods of moderate to locally heavy rainfall will be possible, with showers capable of redeveloping and frequently filtering over the same areas for extended durations, and with the heaviest thunderstorm activity expected during this period. As a result, the threat for localized flooding will increase, especially in urban and poor drainage locations.

Overall, while shower coverage and intensity will fluctuate through the period, the greatest concern remains after Wednesday, when periods of heavy rainfall may lead to localized flooding, particularly in urban and poor drainage areas. This same time frame will also carry the highest risk for lightning associated with embedded thunderstorm activity. Winds are expected to remain generally from the east to northeast in the 17 to 20 mph range, which may limit widespread flooding but still allow for locally enhanced rainfall in favored areas. Temperatures are expected to remain near seasonal norms, with no significant heat impacts anticipated.

AVIATION

(06Z TAFS) Issued at 415 AM AST Sat Jan 17 2026

VFR conds expcd to prevail across all TAF sites thru the fcst pd. A patch of low-lvl moisture will bring SHRA thru 17/16Z, with another incrs aft 17/23Z, resulting in fast-moving SHRA that may brfly reduce CIGs/VIS, though no sig or prolonged restrs are expcd. ENE winds at 812 kt early will incrs to 1520 kt with gusts arnd 30 kt aft 17/13Z, with 1020 kt winds persisting aft 17/23Z, resulting in windy conds, esp at exposed terminals.

MARINE

Issued at 415 AM AST Sat Jan 17 2026

A broad surface high pressure will continue to strengthen over the central Atlantic during the next few days. Fresh to locally strong east to northeast winds, and the arrival of a long-period northerly swell will result in choppy to rough seas, leading to hazardous marine conditions during the weekend.

BEACH FORECAST

Issued at 415 AM AST Sat Jan 17 2026

The moderate risk of rip currents along all the northern-exposed beaches of Puerto Rico and the U.S. Virgin Islands will remain favorable through this afternoon. However, conditions are expected to deteriorate afterwards and persist through the weekend.

Model guidance continues to suggest a northerly swell moving into the local waters, combining with rough seas generated by breezy conditions. This pattern will lead to increasingly large breaking waves and stronger nearshore currents, particularly along the north and northeast-facing beaches of Puerto Rico, including Culebra, as well as exposed beaches across the U.S. Virgin Islands.

As a result, a high risk of rip currents will be in effect from this afternoon into early next week posing hazardous conditions for swimmers and beachgoers. Beachgoers are urged to exercise caution, follow guidance from local authorities, and avoid entering the water in areas under a high rip current risk.

For localized and updated risk levels, visit weather.gov/beach/sju.

SJU WATCHES/WARNINGS/ADVISORIES

PR...High Rip Current Risk from this evening through late Sunday night for PRZ001-002-005-008-012.

VI...High Rip Current Risk from this evening through late Sunday night for VIZ001-002.

AM...Small Craft Advisory from 2 PM this afternoon to 2 PM AST Monday for AMZ711.

Small Craft Advisory from 6 PM this evening to 6 PM AST Sunday for AMZ712-716-726-733-741.

Small Craft Advisory from 6 PM this evening to 2 PM AST Monday for AMZ723.