AFDSJU Area Forecast Discussion National Weather Service San Juan PR 125 PM AST Thu Dec 25 2025 ...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST... .KEY MESSAGES... Issued at 108 PM AST Thu Dec 25 2025 * Hazardous marine and coastal conditions will continue today across the Atlantic waters and north- and east-facing beaches, although a gradual improvement is expected later today. Small Craft Advisories and High Surf Advisories are expected to expire later today or tonight, but conditions may remain dangerous for small vessels and near the shoreline. * Life-threatening rip currents will persist through the weekend, even as surf heights lower. Swimming is strongly discouraged, and beach conditions may deteriorate again late Friday into Saturday as another northerly swell increases marine and coastal hazards. * Weather conditions will trend drier and more stable through the weekend, with cooler temperatures and only brief, passing showers mainly affecting northern and eastern areas during the overnight and early morning hours. * U.S. Virgin Islands: Marine and beach hazards will persist, with dangerous rip currents remaining the primary concern, and a potential increase in hazardous conditions late Friday into the weekend. && .Short Term(This evening through Saturday)... Issued at 108 PM AST Thu Dec 25 2025 An unsettled pattern was observed during the morning hours, with cloudiness and showers across the northeastern and eastern interior of Puerto Rico and the U.S. Virgin Islands. The strongest shower activity was observed across the San Juan Metro area, where rainfall accumulations were near an inch. As of 11 AM, the remnants of the frontal boundary moved slightly southward, and a drier airmass with precipitable water values ranging from 1.0 to 1.1 inches moved into the region. These surface conditions led to a significant reduction in cloudiness and showers across most of the area. Some showers remained across eastern sections of Puerto Rico and the U.S. Virgin Islands, but rainfall accumulations were insignificant. A more tranquil and stable weather pattern is forecast for tonight into Friday as a surface high pressure system over the western Atlantic dominates the region within a north-northeasterly wind flow. The surface-to-3 km wind flow will allow temperatures to drop, as suggested by the 925 mb temperature. Therefore, residents can expect cool nights in the coming days, with lows in the 50s at the highest elevations and in the 60s and low 70s at lower elevations. It will warm up during the day, with highs mostly in the 70s in the mountains and in the low 80s along the coast. In terms of shower probabilities, although surface conditions will remain mostly favorable for a drier trend, some brief, short-lived showers cannot be ruled out due to colder temperatures at 500 mb between -10 and -9 degrees and lower heights at 250 mb. Under the northeasterly wind flow and advective pattern, showers are forecast during the early morning and late evening along the Atlantic waters, moving southward and streaming across the north coast. && .Long Term(Sunday through next Wednesday)... Issued at 338 AM AST Thu Dec 25 2025 The long-term forecast remains unchanged. Drier air behind a frontal boundary will dominate the region through Monday, with precipitable water (PWAT) values falling well below 1.0 inch. However, isolated patches of moisture may occasionally move across the area, promoting brief passing showers. Despite the prevailing dry pattern early in the period, a building surface high over the western Atlantic and a frontal low over the north-central Atlantic will promote a northeasterly steering flow through Monday. 925 mb temperatures are expected to remain below two standard deviations for this time of year, supporting cooler-than- usual conditions. Later in the workweek, temperatures are forecast to moderate back to near-normal values. Latest model guidance suggests that winds will gradually veer by Tuesday, becoming southeasterly, allowing Caribbean moisture to filter across Puerto Rico and the U.S. Virgin Islands. Along with this wind shift, a trough moving across the area will result in a wetter pattern, with increasing chances for showers and isolated thunderstorms by midweek. Confidence regarding the specific timing and impacts remains medium. Therefore, residents and visitors are encouraged to continue monitoring the forecast, as more active weather conditions could develop. && .AVIATION... (18Z TAFS) Issued at 108 PM AST Thu Dec 25 2025 VFR conditions will persist for all TAF sites during the period. Surface winds will remain from the N-NE up to 15 knots with gusty winds. Some cloudiness and a few passing showers will result in VCSH across eastern sites, but with no operational impacts. Winds will persist from the N-NE, diminishing at around 26/03Z, and increasing up to 15 knots at 26/14Z. Some -RA and -SHRA are possible across TJSJ, TIST, & TISX from 26/00Z-26/12Z. && .MARINE... Issued at 108 PM AST Thu Dec 25 2025 A long-period northerly swell associated with a diminishing frontal system continues to affect the offshore and nearshore Atlantic waters and passages. However, recent nearshore and offshore buoy observations indicate that swell energy is gradually diminishing, with significant wave heights showing a slow downward trend. Seas will remain choppy to rough across the Atlantic waters, but conditions are expected to fall below Small Craft Advisory criteria later tonight, allowing current advisories to likely expire. Despite this temporary improvement, hazardous marine conditions are likely to return this weekend. Another pulse of long-period northerly swell is expected to arrive late Friday into early Saturday, which may once again build seas to advisory levels across the offshore and exposed Atlantic waters. As a result, Small Craft Advisories may need to be reissued, particularly for small and inexperienced vessels. Mariners should continue to closely monitor forecasts, as conditions may deteriorate again heading into the weekend. && .BEACH FORECAST... Issued at 108 PM AST Thu Dec 25 2025 Hazardous coastal conditions will continue across the Atlantic- facing beaches of Puerto Rico and the U.S. Virgin Islands, although observations show that the current northerly swell is slowly subsiding. This gradual decrease in swell energy should allow High Surf Advisories to expire later today, as breaking wave heights trend downward through the afternoon and evening. However, impacts remain significant. The lingering long-period swell will continue to produce life-threatening rip currents, and High Rip Current Risk will persist through the weekend. These conditions pose an extreme danger to swimmers, even as surf heights fall below advisory thresholds. Additionally, another northerly swell arriving Friday night into Saturday is expected to reinforce hazardous rip current conditions and could once again increase breaking wave heights along north- and east-facing beaches. While it is too early to determine exact surf magnitudes, High Surf Advisories cannot be ruled out with this next swell event. Beachgoers are strongly urged to remain out of the water, especially at unguarded beaches, and heed all local beach safety statements and advisories. For further information, refer to the Coastal Hazard Message (CFWSJU). For localized and updated risk levels, visit weather.gov/beach/sju. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...High Rip Current Risk through Friday afternoon for PRZ001-002- 005-008-010. High Surf Advisory until 6 PM AST this evening for PRZ001-002- 005-008-010. High Rip Current Risk through late tonight for PRZ012. High Rip Current Risk until 6 PM AST this evening for PRZ013. VI...High Rip Current Risk through late tonight for VIZ001. High Rip Current Risk until 6 PM AST this evening for VIZ002. AM...Small Craft Advisory until midnight AST tonight for AMZ711-712- 716-723-726-741-742. && $$ SHORT TERM/AVIATION...LIS