AFDSJU Area Forecast Discussion National Weather Service San Juan PR 229 PM AST Sat Jan 17 2026 ...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST... .KEY MESSAGES... Issued at 1241 PM AST Sat Jan 17 2026 * Marine and beach conditions will continue to deteriorate this evening, resulting in hazardous seas and a high risk of rip currents. Small Craft and beachgoers are encouraged to exercise caution and follow the flag warning system respectively. * Breezy to windy conditions could lead for unsecured items to be blown around, with outdoor objects potentially displaced in the most exposed locations. * Trade wind passing showers will continue across the local waters and windward sections, resulting in slippery roads and ponding of water in low-lying and poor drainage areas. && .Short Term(This evening through Monday)... Issued at 1241 PM AST Sat Jan 17 2026 During the early morning hours, a pronounced wind surge moved across the U.S. Virgin Islands and progressed westward across Puerto Rico by mid-morning. This feature produced a brief period of isolated to scattered showers accompanied by gusty winds. While some showers were occasionally moderate, they were fast-moving, resulting in minimal rainfall accumulations. Surface observations indicated gusts in the upper 20s to low 30s mph across the smaller islands and exposed coastal areas of Puerto Rico, with a peak wind gust of 36 mph reported at the Henry E. Rohlsen Airport. In the wake of the wind surge, a notable intrusion of dry air has overspread the region. GOES-19 precipitable water imagery indicates PWAT values near 1.0 inch, well below climatological normals for this time of year. This has resulted in clearing skies and fair weather conditions, which are expected to persist through the remainder of the afternoon hours. Despite improving sky conditions, breezy to locally windy conditions will continue, particularly along the coasts and higher elevations, as a tight pressure gradient remains in place. For the remainder of the short-term period, the overall forecast remains largely unchanged. Moderate to fresh easterly trade winds will persist tonight through Sunday, maintaining breezy to locally windy conditions across much of the area. The prevailing dry air mass will limit shower activity, with any passing showers remaining brief and shallow, mainly affecting windward coastal areas during the nighttime and early morning hours. No significant rainfall accumulations are expected, though brief ponding in poor drainage areas cannot be completely ruled out. By late Sunday into early Monday, a modest increase in low-level moisture may allow for a slight uptick in passing trade-wind showers, particularly across eastern and northeastern Puerto Rico and the U.S. Virgin Islands. Even so, overall conditions will remain generally fair, with wind-related hazards continuing to be the primary concern. Residents should remain alert for gusty winds, especially in exposed locations, while outdoor conditions outside of brief showers will remain favorable. && .Long Term(Tuesday through next Friday)... 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... (18Z TAFS) Issued at 1241 PM AST Sat Jan 17 2026 VFR conds expected at all terminals through the fcst pd. Limited SHRA activity due to a dry airmass, with only brief VCSH psbl mainly across USVI and E PR terminals. No sig flight restrs anticipated. ENE winds 1525 kt with gusts up to 30 kt will result in windy conds, esp at exposed coastal terminals. && .MARINE... Issued at 1241 PM AST Sat Jan 17 2026 A broad surface high pressure will continue to strengthen over the central Atlantic today, promoting fresh to locally strong easterly winds. This, combined with the arrival of a long- period north-northwesterly swell, will result in choppy to rough seas, leading to hazardous marine conditions for small craft. Hence, Small Craft Advisories remain in effect for the local Atlantic waters and offshore Caribbean, including the Mona and Anegada Passage through at least Monday afternoon. Small craft operators are urged to exercise caution. && .BEACH FORECAST... Issued at 1241 PM AST Sat Jan 17 2026 No changes were introduced to the beach forecast. Currently, the moderate risk of rip current continues across northern and eastern beaches of Puerto Rico, including Vieques and Culebra, and St. Croix in the U.S. Virgin Islands. Low elsewhere. Conditions are expected to deteriorate in the evening hours as strengthening winds and a north-northwesterly long-period swell spreads across the local waters and passages. Hence, a Rip Current Statement remains in effect for the north and east-facing beaches of Puerto Rico, including Culebra, and the U.S. Virgin Islands from 6 PM AST tonight through 6 AM AST on Monday. Residents and visitors are urged to follow the warning flag system and to opt for beaches with lower risk such as the western and southern beaches of Puerto Rico. Besides rip currents, beachgoers should exercise caution due breezy to windy conditions across the coastal areas of the islands. Unsecured objects may blown around, with outdoor objects potentially displaced in the most exposed locations. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...High Rip Current Risk from 6 PM AST this evening through late Sunday night for PRZ001-002-005-008-012. VI...High Rip Current Risk from 6 PM AST this evening through late Sunday night for VIZ001-002. AM...Small Craft Advisory until 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. && $$