Area Forecast Discussion
Issued by NWS San Juan, PR
Issued by NWS San Juan, PR
308 FXCA62 TJSJ 301857 AFDSJU Area Forecast Discussion National Weather Service San Juan PR 257 PM AST Sun Nov 30 2025 ...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST... .KEY MESSAGES... Issued at 204 PM AST Sun Nov 30 2025 * Breezy to locally windy conditions will prevail through at least Monday, promoting choppy to rough seas. Therefore, there is a Small Craft Advisory for the Offshore Atlantic waters. * Showers and isolated thunderstorms will continue through the evening, increasing flooding risk across portions of western and southwestern Puerto Rico. * The US Virgin Islands and Puerto Rico should experience pleasant temperatures throughout the forecast period. && .Short Term(This evening through Tuesday)... Issued at 204 PM AST Sun Nov 30 2025 Dry mid-level conditions remain evident in the 12Z TJSJ sounding, which sampled 700-500 mb relative humidity near 35 to 45 percent. Persistent easterly flow continues to favor brief, fast-moving showers across Puerto Rico and the U.S. Virgin Islands. Afternoon convective growth will remain shallow, with only isolated activity expected along the Cordillera Central before dissipating around sunset. Tonight and Monday, the typical overnight and early-morning trade- wind shower pattern will continue, mainly affecting eastern Puerto Rico, the U.S. Virgin Islands, and regional waters. PWAT values will remain near 1.4 to 1.7 inches, close to seasonal averages, with mid- level humidity also remaining within normal levels. This will support continued quick-passing showers with limited flooding threat. Beginning late Monday and continuing into Tuesday, dynamics will become more favorable as a surface trough approaches from the east, induced by a strengthening upper-level trough. Model guidance suggests 250-mb height fields dropping to below-normal levels, along with steeper 700500 mb lapse rates as 500-mb temperatures cool to around 9 degrees Celsius. These changes will support somewhat more favorable conditions for afternoon convection. Moisture levels may remain a limiting factor. Nevertheless, the frequency of showers is expected to increase by late Monday into Tuesday, especially across western and interior Puerto Rico under sea-breeze convergence. Winds will remain from the east to east-northeast at 15 to 20 mph, with higher gusts in exposed areas. However, the pressure gradient is expected to diminish over the next few days, resulting in lower wind speeds, particularly on Tuesday. This could enhance rainfall accumulations during this period. && .Long Term(Wednesday through next Saturday)... Issued at 545 AM AST Sun Nov 30 2025 An upper-level trough will continue to approach the region midweek, extending its influence into the mid-levels. This pattern will bring a moderate chance of instability (around 40 to 60 percent) across Puerto Rico and the U.S. Virgin Islands from Wednesday through the end of the workweek. At the same time, an easterly disturbance will approach the islands, maintaining a humid and somewhat unsettled weather pattern during this period. Thursday currently has the highest probability of additional weather, with deeper moisture and instability supporting a 50 to 70 percent chance of scattered to numerous showers and isolated thunderstorms. These thunderstorms could temporarily affect outdoor activities. Additionally, if frequent showers develop over the same areas, localized flooding may occur in regions with poor drainage. Therefore, we anticipate a limited flooding risk, particularly over PR. From late Friday into Saturday, a high-pressure system over the western Atlantic will move north of the islands. As it does so, the high pressure will help weaken the trough, promoting a more stable environment. However, lingering moisture (30 to 50 percent chance of showers) will continue to support occasional showers, especially during the overnight and early-morning hours. && .AVIATION... (18Z TAFS) Issued at 204 PM AST Sun Nov 30 2025 SHRA/VCSH will continue across the local terminals through the period, with brief MVFR CIGS possible at all TAF sites. VCTS expected at TJBQ and TJPS aft 17Z due to afternoon convection over the interior and west. Winds EENE 1220 kt with higher gusts through the afternoon, then diminishing blo 10 kt aft 30/23Z as land- breeze flow sets in, becoming variable overnight. VFR will prevail outside brief SHRA/VCTS. && .MARINE... Issued at 204 PM AST Sun Nov 30 2025 A surface high pressure over the Central Atlantic, interacting with a cold front moving eastward across the western Atlantic, will promote E- NE moderate to locally fresh winds tonight through Tuesday. This will result in choppy to rough seas across most offshore waters and passages, particularly those offshore Atlantic waters. Therefore, a small craft advisory continues in effect across the Atlantic offshore waters. As a surface trough approaches the CWA, winds will briefly gentle to moderate by Tuesday night, becoming moderate from the east late Wednesday night. && .BEACH FORECAST... Issued at 204 PM AST Sun Nov 30 2025 No major changes were introduced to the beach forecast. The moderate risk of rip continues along north and east-facing beaches of Puerto Rico, including Vieques and Culebra, and the U.S. Virgin islands. Low elsewhere. As winds are likely to decrease, rip current risk should gradually improve in some areas through the week, spreading once again by the end of the week. Visitors and residents are encouraged to always swim near a lifeguard. Additional to rip currents, beachgoers should stay weather alert as showers and isolated thunderstorms may move over coastal areas of the islands. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...Small Craft Advisory until 6 AM AST Monday for AMZ711. && $$ SHORT TERM/AVIATION...CVB LONG TERM...MMC MARINE/BEACH FORECAST...MNG