Area Forecast Discussion
Issued by NWS San Juan, PR
Issued by NWS San Juan, PR
274 FXCA62 TJSJ 111907 AFDSJU Area Forecast Discussion National Weather Service San Juan PR 307 PM AST Tue Nov 11 2025 ...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST... .KEY MESSAGES... Issued at 249 PM AST Tue Nov 11 2025 * The US Virgin Islands and Puerto Rico can expect mainly clear skies, with winds pushing patches of moisture and clouds, along with occasional showers, throughout the forecast period. * A long-period north-northwesterly swell will worsen marine conditions along the Atlantic and Caribbean Passages. This swell is expected to create life-threatening rip currents along the north- and east-facing beaches in Puerto Rico and the US Virgin Islands between Thursday and Friday. * There is a moderate chance that the weather turns wetter and more unstable due to a frontal boundary approaching from the western Atlantic near the northeast Caribbean around Saturday or Sunday. && .Short Term(This evening through Thursday)... Issued at 249 PM AST Tue Nov 11 2025 The US Virgin Islands experienced scattered showers early in the morning associated with a patch of moisture with embedded clouds and showers. By mid-morning, those clouds reached eastern Puerto Rico, but produced less shower activity than in the northern USVI. In general, the region experienced calm weather conditions, with heat index values ranging from 100 to 106 degrees Fahrenheit, due to the combination of high maximum temperatures and available moisture. Shallow afternoon convection developed along the Cordillera Central and western PR, as well as downwind from the US Virgin Islands. Winds were predominantly from the east, with speeds ranging from 10 to 20 mph, and higher gusts and variations in the sea breeze. A mid-to-upper-level ridge over the Northeast Caribbean will promote stable weather in the short term. At the surface, a high pressure across the Central Atlantic will interact with a frontal boundary moving eastward across the Western Atlantic. This pattern will create an easterly wind flow, which will become more northeasterly by Wednesday. As a mid-to-upper-level trough amplifies from the northwest near the region, the ridge pattern aloft will gradually weaken. This may result in a slight chance of one or two isolated thunderstorms by Thursday afternoon, as sea breezes, local effects, and daytime heating contribute to enhanced convection. However, we have not included these potential thunderstorms in the current forecast package. That said, we expect a seasonal weather pattern, dominated by the advection of pockets of moisture that will bring periods of moderate to locally heavy rain at times, mainly across the local waters and moving inland across the US Virgin Islands or PR`s windward locations. Afternoon convection will be confined to the interior and western locations in PR, due to local effects, except for Thursday, when more coverage is more likely. && .Long Term(Friday through next Monday)... Issued at 249 PM AST Tue Nov 11 2025 A variable weather pattern is expected through the long term period as a frontal boundary moves southward during the first part of the forecast. From Friday into early Saturday, the local islands will be dominated by an easterly wind flow. Under this pattern, patches of shallow moisture with precipitable water values between 1.2 and 1.6 inches will persist, remaining near climatological normals. Although some moisture will be present, a mid- to upper-level ridge will limit shower development across most areas, leaving a moderate to high chance of afternoon showers over the western interior on Friday. Late Saturday into the upcoming workweek, the surface pattern will shift as the frontal boundary approaches and weakens the pressure gradient. Winds will veer from the north-northwest late Saturday into Sunday, increasing the potential for passing showers due to a cold advection pattern. This setup will promote showers across the coastal waters and portions of the northern coast during the morning and evening hours. However, significant rainfall accumulations are not anticipated during this period. A surface high pressure building over the western portion of the Central Atlantic will weaken the frontal boundary early next week, returning the local flow to an east-southeast direction from Monday into Tuesday. This will promote a more typical weather regime with heat indices possibly reaching 108 degrees in some areas, followed by afternoon convection across the interior and western Puerto Rico. && .AVIATION... (18Z TAFS) Issued at 249 PM AST Tue Nov 11 2025 Expect VFR conds through the forecast period. Occasional SHRA/+SHRA will affect local terminals and surrounding waters, leaving none to minimal impacts to operations. Western PR afternoon convection will mainly impact the VCTY of JBQ thru 11/23z. Winds will remain mainly from the east at 10-15 kt, with occasional higher gusts and sea breeze variations, mainly during the morning and afternoon hours. Overnight, we expect calm to light and VRB winds. && .MARINE... Issued at 249 PM AST Tue Nov 11 2025 A broad surface high pressure extending from the north into the Central Atlantic will maintain a moderate to locally fresh easterly wind flow across the regional waters. A north- northwesterly swell will will arrive as early as late Wednesday night, increasing seas and producing hazardous marine conditions across the offshore Atlantic waters and Caribbean Passages. Seas are expected to build to around 7 feet, and Small Craft Advisories will be required. && .BEACH FORECAST... Issued at 249 PM AST Tue Nov 11 2025 A moderate risk of rip currents will persist through this evening, when is forecast to turn low from tonight through Wednesday evening. Then, a north-northwesterly swell will create hazardous coastal conditions, from late Wednesday night through at least Friday. Thus, beachgoers can expect life-threatening rip currents along the north-facing beaches in PR and the US Virgin Islands. Visitors and residents should remain alert and stay tuned for updates to the rip current risk forecast. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. && $$ MORNING CREW...CAM/MNG EVENING CREW...ICP/MRR