AFDSJU Area Forecast Discussion National Weather Service San Juan PR 200 PM AST Wed Jan 28 2026 ...New SHORT TERM, AVIATION, MARINE, BEACH FORECAST... .KEY MESSAGES... Issued at 200 PM AST Wed Jan 28 2026 * Relatively stable weather conditions are expected through Friday, with brief morning showers across eastern areas of Puerto Rico and the USVI and afternoon showers developing over western Puerto Rico; minor ponding on roads is possible. * There is an increasing risk of urban and small stream flooding from the weekend into early next week as a frontal boundary approaches from the west of the region. * Dangerous swimming conditions and hazardous seas are expected along the Atlantic coastlines and coastal waters by early next week as swell action spreads across the region. * For the U.S. Virgin Islands, the primary hazard will remain dangerous swimming conditions and hazardous seas early next week. While moisture is expected to increase during the weekend, most of the weather is currently forecast to stay west of the islands. && .Short Term(This evening through Friday)... Issued at 200 PM AST Wed Jan 28 2026 Mostly sunny skies prevailed across Puerto Rico and the U.S. Virgin Islands during the morning hours, becoming variably cloudy during the afternoon. Temperatures reached the mid-80s under light to moderate easterly winds. Continue to expect passing showers across eastern sections of Puerto Rico and the U.S. Virgin Islands this afternoon and tonight as an area of cloudiness and associated low-level moisture moves across the forecast area. As this moisture progresses, locally induced showers cannot be ruled out across western Puerto Rico this afternoon. Nevertheless, due to limited upper-level forcing and precipitable water values remaining near or below climatological normals, the primary threat will remain ponding of water on roadways and in low-lying areas. On Thursday, a similar weather pattern is expected to persist under a weakening mid- to upper-level trough and light to moderate east-southeasterly winds. However, ensemble guidance suggests Friday night into Saturday as a transition period, with moisture gradually increasing under a more southeasterly flow. As a result, shower frequency is expected to increase across eastern Puerto Rico and the U.S. Virgin Islands, and the risk of flooding is anticipated to rise toward the end of the forecast period. No changes in terms of Tmax and Tmin with temperatures at the 925 mb level remaining slightly above climatological normals. Maximum temperatures are forecast to reach the mid-80s in lower elevations and the mid-to-upper 70s across the higher terrain. && .LONG TERM...(Saturday through Wednesday)... Issued at 422 AM AST Wed Jan 28 2026 The synoptic pattern is forecast to remain generally unchanged through the long-term period, with a frontal boundary lingering near the local area. A southerly to southeasterly low-level flow ahead of this boundary will persist, continuing to advect warm and moist air across Puerto Rico and the U.S. Virgin Islands. As a result, above- normal temperatures are expected to persist through the period. Global model guidance continues to indicate an increase in available moisture beginning Saturday, with precipitable water values rising to near 2.0 inches or higher and remaining above climatological normals through early next week. Low- to mid-level moisture, particularly below 700 mb, is forecast to remain elevated. Although some drying at mid levels (around 700-500 mb) is suggested at times, the overall moisture profile should remain sufficient to support periods of enhanced shower and thunderstorm activity. At upper levels, the region is expected to remain between an upper- level trough over the western Atlantic and a ridge to the southeast, providing periods of favorable upper-level dynamics depending on the exact placement and evolution of these features. This pattern, combined with persistent low-level moisture convergence along the nearby frontal boundary, will support increasing rainfall coverage, particularly from Sunday through Tuesday. Recent guidance continues to suggest a signal for above-normal rainfall across portions of the forecast area early next week. Of note, ECMWF Extreme Forecast Index output consistently highlights a rainfall signal several days in advance, which is somewhat surprising given the lead time and suggests increasing ensemble agreement toward a wetter-than-normal pattern. While confidence in the exact timing, magnitude, and spatial distribution of rainfall remains limited at this range, the persistence of the signal supports a continued potential for locally heavy rainfall, especially where showers and thunderstorms repeatedly affect the same areas. Some uncertainty remains with respect to the exact placement of the frontal boundary, as a westward position closer to Hispaniola would result in reduced low-level convergence and consequently less widespread shower and thunderstorm coverage across the local forecast area. Diurnal heating, local effects, and sea breeze convergence will continue to play a role in convective development each afternoon, depending on the persistence of cloud cover, mainly across interior and western to northwestern Puerto Rico. Potential impacts include ponding of water on roadways, urban and small stream flooding, and localized flooding, particularly in areas that receive repeated rounds of rainfall. Gusty winds may accompany heavier showers or isolated thunderstorms. Overall, the long-term period is expected to remain unsettled, with the primary concerns being above-normal rainfall and localized flooding potential through at least Tuesday. && .AVIATION... (18Z TAFS) Issued at 200 PM AST Wed Jan 28 2026 Mainly VFR conditions expected to prevail across all TAF sites during the next 24 hrs. VCSH or -SHRA are more likely across TJBQ and TJSJ thru 28/22Z. Brief periods of reduced vis and low cigs can be anticipated. Aft 28/23Z, passing showers are expected across TISX. Aft 29/15-17Z, VCSH are possible across TJPS and TJBQ again. E to SE winds around 13 kts or below generally becoming lighter after 29/00Z, then picking up again around 29/14-15Z. && .MARINE... Issued at 200 PM AST Wed Jan 28 2026 Light to moderate easterly winds will persist through the end of the week as surface high pressure shifts eastward, with seas generally subsiding across the local waters. By early next week, a long-period northwesterly to northerly swell is expected to reach the regional waters by Monday. This swell, combined with strengthening winds, will likely result in choppy to rough seas and potentially hazardous marine conditions, including Small Craft Advisory criteria, especially across the offshore Atlantic waters and local passages. An increase in shower and thunderstorm activity is also anticipated from this weekend into early next week, particularly over the northwestern Atlantic waters and the Mona Passage, with an increasing potential to observe lightning and gusty winds. && .BEACH FORECAST... Issued at 200 PM AST Wed Jan 28 2026 Pulses of weak northerly swells will continue to affect the Atlantic waters through the remainder of the week, with the strongest pulse expected tomorrow, Thursday afternoon. A generally moderate risk of rip currents is expected along most north-facing beaches of the islands, however, a high rip current risk cannot be ruled out on Thursday, when life-threatening rip currents may develop. Beachgoers are encouraged to monitor the forecast for updates and changing conditions. Residents and visitors should also note that beach conditions may further deteriorate early next week due to increasing winds and the arrival of a stronger northwesterly to northerly long-period swell, potentially leading to hazardous beach conditions. Additionally, a change in the weather pattern may bring showers and thunderstorms from this weekend into early next week, increasing risks for beachgoers. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. && $$