Area Forecast Discussion
Issued by NWS San Juan, PR
Issued by NWS San Juan, PR
777 FXCA62 TJSJ 252031 AFDSJU Area Forecast Discussion National Weather Service San Juan PR 431 PM AST Fri Apr 25 2025 .SYNOPSIS... Moisture content will start to increase from tonight onwards leading to showers across the U.S. Virgin Islands and surrounding waters, then scattered to numerous showers with isolated thunderstorms each afternoon across the interior and northern sections of Puerto Rico. A unstable and wetter weather pattern will prevail during the weekend into next week. A northeasterly swell will reach the Atlantic waters resulting in a high risk of rip currents on Sunday. Residents and visitors are encouraged to stay informed by monitoring official forecast updates. && .SHORT TERM...Tonight through Sunday... Mostly clear skies prevailed across PR and the USVI during the morning hours. However, a line of heavy showers affected the island of St Croix late this morning into the afternoon hours, producing water ponding in roads. Then, increased cloudiness developed along the Cordillera Central and by the afternoon hours periods of locally heavy rains developed particularly over municipalities like San Sebastian, Utuado, Adjuntas, Caguas and additional municipalities with rainfall accumulation between 0.20 and 0.70. The maximum temperatures range mainly in the mid and upper 80s along the coastal areas and in the mid to upper 70s along the higher terrains. Sea breeze dominates the local winds along the coastal sections today. After today`s rain activity we expect a broad area of above-normal moisture to gradually move over the region from the east. This increase in moisture will promote showers and isolated thunderstorms to develop across the surrounding waters, moving inland occasionally across the U.S. Virgin Islands, Vieques, Culebra, and parts of eastern Puerto Rico. Thus we anticipate a limited flooding threat overnight into tomorrow morning. Increasing instability is expected from now onward. Under this weather pattern, periods of intensive rains can be anticipated, especially from afternoon to evening across the islands. Saturday afternoon into the evening is the most active period of the short- term forecast. Although a deep-layered trough is near the region, some limiting factors we are observing are the propagation of the expected moisture and where it might be located before interacting with the instability provided by the upper-level feature. Additionally, some guidance suggests a mid- to upper-level cloud deck filtering over the region by Sunday. This cloudiness might negatively impact the formation of convection by reducing diurnal heating, which might be one of the principal triggers of this activity. Regardless of these factors, we can anticipate the transition to an unstable and wet pattern from this evening through early next week and into the middle of next week. Under this weather scenario, the main meteorological threats are flooding rains, frequent lightning, and strong winds due to thunderstorms, along with the potential for landslides in areas of steep terrain, particularly in locations that remain vulnerable due to excessive rainfall during the past weekend. Please continue to monitor the weather forecast as we approach the weekend. .LONG TERM... && .AVIATION... (18z) TAFS Mainly VFR conds expected at all TAF sites during the period. SHRA will continue over TISX, and most likely reduce CIGs and VIS through 25/20z. Possible VCTS and SHRA after 26/00z for TJSJ, reducing CIG/VIS and promoting MVFR conds btwn 2603/2605. SHRA remains possible for TIST after 25/23z. Light winds will prevail after 25/23z, becoming NE btwn 9-11 kt aft 26/12z. && .MARINE... Light and variable winds will prevail through Saturday, then moderate easterly winds are expected to return by Saturday night. Overall conditions should remain favorable for small craft, but localized hazardous marine conditions may develop near showers and thunderstorms, which are expected to become more active tonight into early next week. A long-period northeasterly swell is expected to spread across the Atlantic waters Saturday night into Sunday, promoting hazardous conditions for small craft. && .BEACH FORECAST... There is a moderate risk of rip currents along the northern and eastern coasts of Puerto Rico including Culebra, which means life- threatening rip currents are still possible in those areas. A low risk remains in place elsewhere. The moderate risk of rip current is expected to expand to the USVI by Saturday. However, the risk is expected to increase to high along north exposed beaches of PR and the USVI by on Sunday, as a northeasterly swell starts to spread across the Atlantic waters from Saturday evening into early next week. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. && $$ SHORT TERM...CAM/MMC LONG TERM...YZR AVIATION...MNG MARINE/BEACH FORECAST...LIS