AFDSJU Area Forecast Discussion National Weather Service San Juan PR 444 AM AST Tue Jan 27 2026 ...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST... .KEY MESSAGES... Issued at 437 AM AST Tue Jan 27 2026 * Small Craft Advisory and High Rip Current Risk are in effect today, as a northerly swell impacts the offshore Atlantic waters and northern exposed beaches. * Hazardous seas and coastal conditions may return this weekend due to the arrival of another northerly swell, potentially affecting the Atlantic waters and north-facing coastlines. * Passing showers will affect the islands at times with afternoon shower activities over western Puerto Rico. At most, ponding of water in roads and poorly drained areas. * There is a medium chance of observing an increase in shower coverage and isolated thunderstorms this weekend as tropical moisture moves into the region, with a potential for locally heavy rainfall. && .Short Term(Today through Thursday)... Issued at 437 AM AST Tue Jan 27 2026 Mostly clear skies gave way to cool temperatures during the overnight hours. Some places in the interior of Puerto Rico registered values below 60 degrees. Coastal areas in the west had lows in the mid and upper 60s, while eastern Puerto Rico and the Virgin Islands saw values in the low and mid 70s. Some showers managed to form across the Caribbean and Atlantic waters, but almost no activity was detected over land areas. The surface high that it`s driving the trade winds from the east southeast is now centered over the eastern Atlantic. The gradient has weaken since yesterday, and winds speeds should be at 10 to 15 mph. Aloft, a ridge is in placed over the central Caribbean, with dry air in the mid levels. The most recent satellite derived precipitable water imagery confirms that a small area of moisture will cross the local islands today. Showers should increase a little in the morning, mostly for eastern Puerto Rico and the Virgin Islands. Since the patch of moisture should cross Puerto Rico at mid- day, it is likely that some showers will develop along the interior and west, leading to ponding of water in roadways and low lying areas. Once this patch of moisture cross, conditions dry out quickly tonight, with dew point depressions of 20 to 30 degrees Celsius expected. For tomorrow and Thursday, the atmosphere becomes more stable, with 500 mb temperatures about two standard deviation warmer than normal. Regardless, the trade winds will continue to carry small patches of moisture near the area. Tomorrow, the probability of precipitation is about 30-40% for the Virgin Islands and eastern Puerto Rico, and 50% for western Puerto Rico in the afternoon hours. However, accumulations are expected to be on the light side. Thursday looks drier once again, at least in the morning and early afternoon hours. Winds will become lighter, and coming from the south-southeasterly. Thicknesses at 1000-850 mb will increase, and hence, it will feel warmer too, with highs in the upper 80s in coastal and low elevated areas. && .Long Term(Friday through Tuesday)... Issued at 437 AM AST Tue Jan 27 2026 The synoptic pattern will remain generally unchanged through the long-term period, with a frontal boundary approaching the region from the northwest. Southerly to southeasterly low-level flow ahead of this boundary will continue, promoting above normal temperatures across Puerto Rico and the U.S. Virgin Islands. Based on the latest global model guidance, Friday is expected to be the relatively less active day of the period, as deeper moisture remains south of the area. Conditions are forecast to become progressively wetter over the weekend as southerly flow strengthens and begins to pull tropical moisture over the region, earlier than indicated in previous model cycles. Precipitable water values are forecast to increase beginning Saturday, rising from near 1.3 inches on Friday to near or above 2.0 inches by Saturday and Sunday, which is well above normal for this time of year. This increase in moisture will support higher shower coverage and rainfall intensity, particularly during the weekend and into early next week. At upper levels, the region will be positioned between an upper- level trough to the northwest and a ridge to the southeast, with favorable dynamics aloft depending on the exact placement and evolution of the trough. Nevertheless, sufficient instability may remain in the vicinity, and when combined with daytime heating, local effects, and sea breeze convergence, isolated thunderstorms cannot be ruled out, mainly during the afternoon hours across interior and northwest/northern Puerto Rico. Locally heavy rainfall will be possible with the strongest convection. Potential impacts include ponding of water in urban and poorly drained areas, as well as localized urban and small stream flooding, particularly from Saturday through Monday. Gusty winds may also accompany heavier showers and any isolated thunderstorms. && .AVIATION... (06Z TAFS) Issued at 437 AM AST Tue Jan 27 2026 Mainly VFR conditions expected to prevail. Moisture surge will increase showers after 14Z along eastern PR/USVI. From 15-21Z, SHRA will develop along the Cordillera Central, likely reaching TJPS at times. Periods of reduced VIS and low ceilings can be expected. && .MARINE... Issued at 437 AM AST Tue Jan 27 2026 Winds are gradually easing as the surface high pressure shifts farther east into the central Atlantic. Moderate to locally fresh easterly winds will prevail through midweek turning light by the end of the week. However, a northerly swell will result in hazardous seas across the offshore Atlantic waters through this evening. Looking ahead to next weekend, another long-period northerly swell is expected to reach the regional Atlantic waters, which may result in hazardous marine conditions once again, particularly across the offshore Atlantic waters. && .BEACH FORECAST... Issued at 437 AM AST Tue Jan 27 2026 Breezy wind conditions across the regional waters are gradually subsiding; however, a northerly swell is moving into the Atlantic waters today. Buoy 41043 is already reporting a swell near 6 feet with periods of 10 to 11 seconds. As a result, estimated breaking waves of approximately 6 to 8 feet are anticipated along the northern exposed beaches of Puerto Rico. These conditions will support a High Risk of rip currents through at least this evening for the north-facing beaches of the island. Across the smaller islands, including Culebra, Vieques, and the U.S. Virgin Islands, lingering swell energy will continue to maintain a moderate to locally high risk of rip currents, especially along north-facing and exposed beaches. Beachgoers are strongly urged to follow local beach safety guidance and avoid entering the water at beaches with posted high rip current risk. For localized and updated rip current information, visit weather.gov/beach/sju. && .SJU WATCHES/WARNINGS/ADVISORIES... PR...High Rip Current Risk through this afternoon for PRZ001-002-005- 008. VI...None. AM...Small Craft Advisory until 6 PM AST this evening for AMZ711. && $$