AFDSJU Area Forecast Discussion National Weather Service San Juan PR 433 AM AST Sat Jan 31 2026 ...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST... .KEY MESSAGES... Issued at 240 AM AST Sat Jan 31 2026 * The flood risk increases from today through midweek. Urban and small stream flooding, localized flash flooding, and minor landslides in areas of steep terrain are possible, particularly from late Sunday through Tuesday. Residents and visitors are urged to avoid small streams, creeks, and other recreational areas near rivers. * Life-threatening rip currents are expected today across the northern beaches from Rincon to Fajardo, Culebra and the northern USVI. A large, long-period northerly swell and increasing winds will bring hazardous seas and life-threatening rip currents across most waters and coastal areas of the islands from Monday onward. Rough surf and life-threatening rip currents are expected. Beach erosion and minor coastal flooding are likely in the most vulnerable coastal areas. * Isolated thunderstorms are possible from the weekend into early next week, bringing localized lightning and brief gusty winds. * Across the USVI, sunny to partly cloudy skies are expected this morning, followed by an increase in cloudiness and shower activity from this afternoon through the rest of the weekend. && .Short Term(Today through Monday)... Issued at 240 AM AST Sat Jan 31 2026 Overnight, conditions were mostly fair across the islands, though passing showers affected portions of the U.S. Virgin Islands, southern and southeastern Puerto Rico. Doppler radar indicated minimal rainfall accumulation. Minimum temperatures ranged from the upper 60s to low 70s in lower elevations, while the higher mountains of Puerto Rico saw the mid 60s, with even cooler temperatures in localized areas such as Jayuya and Adjuntas. Today, moisture will increase as a trough lifts from the southeastern Caribbean into the local area. Analysis shows precipitable water values are well above normal, ranging from 1.75 to 2.00 inches. Consequently, shower frequency will increase throughout the morning across the U.S. Virgin Islands, southern and eastern Puerto Rico, shifting toward the northwestern and northern regions during the afternoon. This moist environment, positioned between a frontal boundary to the west and a ridge to the east will persist through the end of the workweek. Enhanced mid-to-upper-level instability will promote periods of moderate to heavy rainfall and isolated thunderstorms. Starting Monday, the combination of upper-level dynamics and low- level moisture convergence along the frontal boundary will support widespread rain. The flood risk remains limited to elevated throughout the period. Potential impacts include: ponding of water on roadways, urban and small-stream flooding, localized flash flooding and gusty winds near heavier shower activity. Unsettled weather is expected to continue through midweek. While maximum temperatures will be above normal today, slightly warmer conditions are possible from Sunday into Monday. Residents and visitors should closely monitor weather updates, especially when planning outdoor activities. && .Long Term(Tuesday through Saturday)... Issued at 240 AM AST Sat Jan 31 2026 The frontal boundary is expected to linger near the local area through midweek, as a weak area of high pressure rolls from the western Atlantic and passes just north of the area into the central Atlantic by the end of the workweek. A series of deep- layer lows/troughs will continue to move from the western into the north-central Atlantic, promoting colder than normal 500 mb temperatures and favorable conditions for thunderstorm development on Wednesday and Thursday. Another approaching front is expected to reach the local area once again by Saturday. These weather features will keep higher than normal moisture content over the islands, and a wet and unsettled weather period is expected to prevail through the long-term period. Therefore, if the expected weather in the short-term period materializes, any additional excessive period of heavy rainfall over saturated soils will lead to quick flooding and possible minor landslides in areas of steep terrain. Breezy northeasterly winds will prevail through Wednesday, turning more east to southeasterly from Thursday onward, and becoming light and variable on Saturday as the front moves closer to the region. && .AVIATION... (06Z TAFS) Issued at 240 AM AST Sat Jan 31 2026 Mainly VFR conditions across all terminals thru 31/14Z. An approaching trough and a frontal boundary will increase the frequency of SHRA today, affecting TJPS, TJBQ and TJSJ aft31/13-14Z. This may result in tempo MVFR conds across these terminals. SHRA may affect most and all TAF sites. SE winds 1015 kt with sea-breeze variability and ocnl higher gusts near SHRA, weakening overnight, then increasing again on Sunday with sustained winds arnd 1418 kt. && .MARINE... Issued at 240 AM AST Sat Jan 31 2026 Moderate to locally fresh southeasterly winds are expected today. A Small Craft Advisory is in effect for the offshore Atlantic waters due to seas up to 7 feet. Winds and seas are forecast to gradually ease on Sunday. However, by early Monday morning, a large, long-period northerly swell is expected to arrive, building seas up to 12 feet through midweek. In addition, an unsettled weather pattern will bring more frequent showers and isolated thunderstorms, which could locally create hazardous marine conditions or exacerbate existing hazards. && .BEACH FORECAST... Issued at 240 AM AST Sat Jan 31 2026 A lingering northerly swell of around 4 feet will continue to promote a high risk of rip currents across all northern exposed beaches from Rincon to Fajardo, Culebra and the northern U.S. Virgin Islands today. A stronger, long-period northerly to north-northwesterly swell is forecast to arrive Monday and persist through the workweek, which is expected to increase rip current risk to high again, while also raising the potential for high surf and minor coastal flooding, especially during the peak of the event Monday into Tuesday across exposed Atlantic and northwestern coastlines. Beachgoers are urged to monitor future forecasts as conditions evolve. && .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. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...High Rip Current Risk through late tonight for PRZ001-002-005- 008-010-012. VI...High Rip Current Risk through late tonight for VIZ001. AM...Small Craft Advisory from 6 AM this morning to 6 AM AST Sunday for AMZ711. && $$