AFDSJU Area Forecast Discussion National Weather Service San Juan PR 207 PM AST Wed Nov 19 2025 ...New SHORT TERM, AVIATION, MARINE, BEACH FORECAST... .KEY MESSAGES... Issued at 206 PM AST Wed Nov 19 2025 * Life-threatening rip currents are expected along the north and east-facing beaches in Puerto Rico, Culebra, and St. Croix through Thursday afternoon. * A surface trough moving across the region is resulting in showers across eastern into the interior of Puerto Rico and afternoon convection over portions of western Puerto Rico. * Passing showers across the U.S. Virgin islands and its vicinity and eastern Puerto Rico are expected during the overnight hours. * Drier air and cooler temperatures are anticipated from tomorrow into the weekend. && .Short Term(This evening through Friday)... Issued at 206 PM AST Wed Nov 19 2025 A surface trough, now mainly west of the islands, promoted afternoon shower and t-storm activity over the region. Under easterly steering winds, the highest radar estimated accumulations (1.5 in to around 2 inches) were observed mainly over interior to western PR, downwind of Vieques, and over western metro area to north-central PR. Satelite derived precipitable water (PWAT) values show around 1.75 to around 2 inches over the islands. The bulk of moisture associated with the surface trough remained over the Caribbean Sea with PWAT values above 2 inches. Maximum temperatures ranged from the mid-80s to the upper 80s and/or low 90s along coastal and lower elevation areas of the islands. Winds are forecast to back and become more northeasterly later today, steering current showers and t-storms towards the SW quadrant of Puerto Rico. A surface high over the Atlantic and an induced surface trough from an upper-level trough north of the islands will maintain northeasterly steering flow through the rest of the period. By early tomorrow, this steering flow will move the more humid air mass, with 1.8 to 2 inches of PWAT, southward and away from the local islands. As gradually drier air filters in, PWAT values are forecast to continue a decreasing trend for the rest of the period. On Thursday, current model guidance has PWAT values ranging from 1.5 to 1.7 inches and on Friday, PWAT values are forecast at 1.1 to 1.4 inches. A patch of even drier air, with PWAT values around 0.9 to an inch, is forecast to approach the northern waters late Friday and reach the islands to start the long term period. Although this drying trend is forecast, the above mentioned mid to upper trough will approach the islands tomorrow and Friday, eroding the current mid-level ridge, promoting instability and resulting in 500 mb temperatures at slightly below normal to normal values. Afternoon convective showers (with possible isolated t-sotrms) can develop across interior to southwestern PR under northeasterly flow, and advective showers will move over northeastern coastal areas during the morning and night hours. 925 mb temperatures are forecast at low-end normal to below normal values during the period. && .Long Term(Saturday through Wednesday)... Issued at 333 AM AST Wed Nov 19 2025 Confidence remains high for the upcoming weekend forecast, with variability for the first part of the workweek. A surface high pressure building over the western Atlantic will promote northeasterly winds through most of the period. Saturday is anticipated to be the driest day of the long- term, as a cold, drier airmass filters into the region. From the latest model solutions, Precipitable Water (PWAT) values should drop below normal (1.0 - 1.2 inches), with some members suggesting values below the 25th percentile (below 1.0 inch). In terms of instability, with the presence of a mid-level ridge lingering through the period, thunderstorm activity will likely remain limited. Additionally, the Galvez- Davison Index (GDI) keeps suggesting a potential for isolated shallow convection. As mentioned in the previous discussion, patches of moisture are still likely to arrive by early Monday, with PWAT values expected to increase but remain below climatological normal (likely between 1.2 and 1.4 inches, with a low chance of reaching 1.6 inches). The most likely scenario remains, with showers moving into windward sections of the local islands each night into the morning, with afternoon convection over the mountain ranges into southwestern Puerto Rico. Under this weather pattern, rainfall accumulations may not necessarily bring significant flood and lightning potential. As mentioned in previous discussions, the fall in temperatures is expected to continue, with 925 mb temperatures remaining below climatological normal, with Saturday being the coolest day of the period. Once again, the heat threat will remain low for the rest of the forecast period. && .AVIATION... (18Z TAFS) Issued at 206 PM AST Wed Nov 19 2025 VFR conds are present across all TAF sites. Intermittent MVFR conds possible over the next hours due to VCTS or TSRA with reduced vis and lower cigs across TJBQ, TJSJ and TJPS, then will decrease aft 19/22-23Z but may linger near TJSJ and USVI terminals overnight. Winds will remain from the E at around 10 to 12 kts. Lighter winds overnight, increasing near 10 kts aft 20/14Z. Winds from the NE anticipated for Thursday. && .MARINE... Issued at 206 PM AST Wed Nov 19 2025 A surface trough will continue to bring a few showers and isolated thunderstorms across the local waters and passages this afternoon and tonight. Moderate easterly winds will gradually shift more from the northeast tonight as a surface trough moves east of the Leeward Islands. Winds will prevail from the northeast through the weekend. Pulses of north-northeasterly swells will continue to spread across the Atlantic waters and local passages through Thursday afternoon. && .BEACH FORECAST... Issued at 206 PM AST Wed Nov 19 2025 Based on buoy observations, the high rip current risk was extended through Thursday afternoon, as another pulse of a north- northeasterly swell is expected to arrive tonight and peak around Thursday morning. This will promote hazardous conditions for beachgoers along northern and eastern beaches of Puerto Rico, Culebra, and St. Croix in the U.S. Virgin Islands. Then, as that pulse continues to fade, beach conditions will improve by late Thursday night, with a moderate risk of rip currents prevailing across the northern and eastern beaches of PR, Vieques, Culebra, and the U.S. Virgin Islands. Nevertheless, beachgoers are encouraged to swim near a lifeguard as life- threatening rip currents are possible along the surf zone. For location-specific information, visit weather.gov/beach/sju. Aside from rip currents, beachgoers should be also aware of other potential hazards such as lightning and gusty winds due to shower and thunderstorm activity this afternoon and tomorrow that may move over coastal areas. If thunder roars, go indoors! && .SJU WATCHES/WARNINGS/ADVISORIES... PR...High Rip Current Risk through Thursday afternoon for PRZ001-002- 005-008-012. VI...High Rip Current Risk through Thursday afternoon for VIZ002. AM...None. && $$