Puerto Rico and US Virgin Islands from 10NM to 19.5N Marine Forecast
| Rest Of Today...West Winds 5 To 10 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 10 Seconds. Isolated Showers. |
| Tonight...Northwest Winds 10 To 15 Knots, Becoming West After Midnight. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 10 Seconds. Isolated Showers. |
| Thursday...Northwest Winds 10 To 15 Knots. Gusts Up To 25 Knots In The Afternoon. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet, Building To 6 To 8 Feet With Occasional Seas Up To 10 Feet. Dominant Period 11 Seconds. Numerous Showers. |
| Thursday Night...North Winds 10 To 15 Knots. Gusts Up To 25 Knots In The Evening. Seas 8 To 10 Feet With Occasional Seas Up To 11 Feet. Dominant Period 11 Seconds. Isolated Showers. |
| Friday...North Winds 10 To 15 Knots, Becoming Northeast. Seas 6 To 8 Feet With Occasional Seas Up To 10 Feet. Dominant Period 11 Seconds. Isolated Showers. |
| Saturday...East Winds 5 To 10 Knots, Becoming South. Seas 8 To 10 Feet With Occasional Seas Up To 11 Feet. Dominant Period 12 Seconds. Isolated Showers. |
| Sunday...Southwest Winds 5 To 10 Knots, Becoming East. Seas 6 To 8 Feet With Occasional Seas Up To 10 Feet. Dominant Period 14 Seconds. |
| Area Forecast Discussion National Weather Service San Juan PR 246pm AST Sat Oct 24 2026 .Short Term(This evening through Monday)... Issued at 246pm AST Sat Oct 24 2026 Scattered showers moved across portions of southeastern Puerto Rico into the eastern interior during the morning hours. Although these showers were fast-moving, Doppler radar and satellite imagery indicated rainfall accumulations between 0.50 and 1.00 inch, with the highest totals extending from northern Yabucoa to northern Guayama and Cayey. Across the U.S. Virgin Islands, fast- moving showers moved over the area as well; however, no significant accumulations were observed. Warm conditions prevailed across the islands today, with daytime highs reaching the upper 80s to low 90s along coastal and urban areas, and the upper 70s to low 80s in the mountains. Heat indices reached the triple digits across coastal and urban sectors throughout all islands due to abundant moisture and south-southeasterly winds. Because winds have prevailed from the south-southeast for most of the day, heat indices climbed to 105 to 110°F across the north-central municipalities of Puerto Rico. Residents in these areas are encouraged to stay hydrated and seek shade or air-conditioned spaces whenever possible. For the rest of the day, abundant moisture and marginal instability will persist over the region, promoting the development of showers and isolated thunderstorms this afternoon across portions of interior, northern, and northwestern Puerto Rico. These showers are expected to be fast-moving due to moderate to locally breezy winds. However, wherever heavier rains train or linger, localized ponding of water in urban and poorly drained areas remains possible. By Sunday into Monday, model guidance continues to differ on available moisture levels to start the week. The GFS (Global Forecast System) model projects precipitable water (PWAT) values of 2.00 to 2.10 inches (near to above normal), whereas the ECMWF (European Centre for Medium-Range Weather Forecasts) introduces drier air with values between 1.60 and 1.75 inches (below normal) before both models align around 2.00 inches (near-seasonal values) by Monday. Despite Sunday's model discrepancy in moisture content, lingering moisture, daytime heating, sea breeze convergence, and local orographic effects will sustain afternoon showers and isolated thunderstorms, mainly across interior, northern, and western Puerto Rico under prevailing southeasterly wind flow. Meanwhile, brief passing showers will continue to affect the U.S. Virgin Islands and eastern Puerto Rico overnight and during the morning hours. Above-normal temperatures at the 925 mb level will persist through next week, sustaining warm and humid conditions across the islands. Residents and visitors should practice heat safety by drinking plenty of fluids, taking frequent breaks in shaded or air- conditioned environments, and never leaving children or pets in unattended vehicles. .Long Term(Tuesday through Saturday)... Issued at 335am AST Sat Oct 24 2026 Wetter conditions may persist Tuesday, then transition to a seasonal pattern Wednesday onward. A surface high pressure building over the Central Atlantic should maintain a SE-S steering flow, though it will likely remain weak through most of the period as the local pressure gradient weakens due to the interaction of the high with a deep-layered trough. The trough should also interact with a mid to upper-level ridge northeast of the region. The latest model guidance suggests abundant moisture content across the region, with PWAT (Precipitable Water) values reaching well above climatological normal (up to 2.25 inches). Although low to mid levels RH remains high (above 60%), the latest solutions suggest that a portion of the PWAT (Precipitable Water) is also associated with high clouds across the CWA. If cloud cover dominates during Tuesday morning, this may inhibit deeper convection, with mainly an advective pattern over windward areas. Otherwise, showers and thunderstorms over the mountain ranges of Puerto Rico may lead to urban and small stream flooding, without ruling out rapid river rises. Wednesday onwards, PWAT (Precipitable Water) values should drop to seasonal and below normal (between 1.5 and 1.75 inches), as a drier slot filters in the mid levels on Wednesday, followed by another slot in the 850- 700 mb layer. Although the ridge may linger near the area and bring subsidence aloft, the combination of daytime heating, local effects, sea-breeze convergence, and available moisture will be the main driver of convection each afternoon, particularly across the mountain ranges of Puerto Rico into northern/northwestern portions. Additionally, during that period, the vicinity of the Madden-Julian oscillation (MJO) and Kelvin waves may boost upward motion, aiding deep convection. Although the flooding risk should be lower from Wednesday onwards due to the drier air, during the afternoons, isolated thunderstorms could still produce gusty winds and lightning. Marine Issued at 246pm AST Sat Oct 24 2026 A surface high pressure over the central Atlantic continues to promote gentle to moderate, occasionally locally fresh, southeasterly winds across the region. Small Craft should exercise caution, particularly across the Atlantic waters and Mona Passage. Marine conditions are expected to briefly improve on Sunday as the northerly swell gradually subsides. However, another northerly swell is expected to arrive across the local waters by Monday, increasing seas once again and maintaining hazardous marine conditions across the Atlantic waters and passages into the upcoming workweek. Beach Forecast Issued at 246pm AST Sat Oct 24 2026 Through the weekend, the high risk of life-threatening rip currents continues for the northern, western, and eastern coastal areas of Puerto Rico, Culebra, and St. Thomas. As a result, the Rip Current Statement remains in effect through at least late Sunday night. Breaking waves around 6 feet along exposed beaches will continue to produce dangerous swimming conditions. Another pulse of long-period northerly swell is expected to spread across the Atlantic waters by Monday, keeping deteriorated coastal conditions early next week. This additional swell will likely increase breaking wave heigheights and maintain a high risk of life- threatening rip currents along exposed beaches into the upcoming workweek. Beachgoers are strongly urged to avoid entering the water at beaches under a high rip current risk. Heed all beach signs and instructions from lifeguards and local authorities. .SJU WATCHES/WARNINGS/ADVISORIES... PR...High Rip Current Risk through late Sunday night for PRZ001-002- 005-008-010-012. VI...High Rip Current Risk until 6pm AST this evening for VIZ001. AM...None. |
San Juan Radar
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