Northern Puerto Rico out 10NM Marine Forecast
| Today...East Winds 10 To 15 Knots, Increasing To 15 To 20 Knots This Afternoon. Gusts Up To 30 Knots. Seas 5 To 6 Feet. Wave Detail: East 5 Feet At 8 Seconds And North 3 Feet At 13 Seconds. Scattered Showers This Morning, Then Numerous Showers This Afternoon. |
| Tonight...East Winds 15 To 20 Knots, Diminishing To 10 To 15 Knots After Midnight. Gusts Up To 30 Knots. Seas 5 To 6 Feet. Wave Detail: East 5 Feet At 6 Seconds And Northeast 3 Feet At 13 Seconds. Numerous Showers. |
| Sunday...East Winds 10 To 15 Knots With Gusts Up To 25 Knots. Seas 5 To 6 Feet. Wave Detail: East 5 Feet At 7 Seconds And Northwest 2 Feet At 10 Seconds. |
| Sunday Night...Southeast Winds 10 To 15 Knots With Gusts Up To 20 Knots, Diminishing To 5 To 10 Knots After Midnight. Seas 4 To 5 Feet. Wave Detail: East 5 Feet At 8 Seconds And Northwest 2 Feet At 9 Seconds. |
| Monday...East Winds 5 To 10 Knots. Seas 4 To 5 Feet. Wave Detail: Northeast 4 Feet At 9 Seconds And North 2 Feet At 11 Seconds. Scattered Showers In The Afternoon. |
| Monday Night...East Winds 5 To 10 Knots, Diminishing To Around 5 Knots After Midnight. Seas Around 4 Feet. Wave Detail: Northeast 4 Feet At 9 Seconds And North 2 Feet At 10 Seconds. Scattered Showers. |
| Tuesday...East Winds 5 To 10 Knots, Increasing To 10 To 15 Knots In The Afternoon. Seas Around 4 Feet. |
| Tuesday Night...East Winds 10 To 15 Knots, Diminishing To 5 To 10 Knots After Midnight. Seas 4 To 5 Feet. Scattered Showers. |
| Wednesday...East Winds 10 To 15 Knots, Increasing To 15 To 20 Knots In The Afternoon. Seas 5 To 7 Feet. Scattered Showers. |
| Wednesday Night...East Winds 10 To 15 Knots. Seas 6 To 7 Feet. Scattered Showers. |
| Area Forecast Discussion National Weather Service San Juan PR 345am AST Sat Dec 13 2025 .Short Term(Today through Monday)... Issued at 304am AST Sat Dec 13 2025 Today is expected to be the wettest day of the short term period due to a surge of moisture associated with a weak trade wind trough. This increase in moisture content, combined with daytime heating and orographic lift over the Cordillera Central, could lead to scattered to locally numerous showers, over central and western PR. However, a wetter pattern is expected late this afternoon and through tonight across the USVI and most coastal areas northern and southern PR, as well across the eastern half of PR as the trough crosses the local area. The precipitable water content is expected to peak close to 2 inches, well above normal levels. Isolated thunderstorms cannot be ruled out, specially in an advective pattern across the waters between the USVI and eastern PR. Urban and small stream flooding is expected with the trough passage. In contrast, on Sunday a temporary break from the rain is expected as a pocket of drier and more stable air moves in from the east. Based on global guidance, this is evidenced by a significant drop in columnar moisture, with 850-700mb relative humidity levels dropping from near 50% today to 10% on Sunday, resulting in mostly sunny conditions with only isolated showers(0-20%). However, this drier phase will be short lived. As an increase in wind speeds and a subsequent return to higher mid-level moisture content is forecast between late Sunday night into Monday. This suggests that scattered showers(30-50%) will become more likely again as the synoptic pattern influenced by a pre-frontal trough shifts back to a more favorable setup for rainfall. .Long Term(Tuesday through Saturday)... Issued at 304am AST Sat Dec 13 2025 The approach of a frontal system and its associated upper-level trough over the western Atlantic will promote unstable conditions during the first half of the long term period. Normal to slightly above-normal precipitable water content (PWAT) of 1.75 to 1.90 inches will enhance the potential for shower development across the region. Showers are most likely over portions of eastern Puerto Rico and the U.S. Virgin Islands during the overnight and morning hours, followed by afternoon showers over portions of central and western Puerto Rico. During this period, the 500 mb temperatures are expected to drop into the -6C to -7C range, meaning the potential for afternoon thunderstorms, particularly across western Puerto Rico, cannot be ruled out. At the surface, a strong high-pressure system located over the central Atlantic will maintain an east-southeasterly wind flow across the area, promoting slightly higher than normal temperatures throughout the week. However, by the second half of the long-term period, another high-pressure system is expected to build over the western Atlantic behind the frontal system. By then, winds are expected to shift from the northeast, leading to cooler temperatures into the northeastern Caribbean region. Marine Issued at 304am AST Sat Dec 13 2025 A surface high pressure system will continue to build near the Azores through the weekend. A weak cold front and another surface high pressure system will move from the western Atlantic into the central Atlantic over the next few days. This pattern will promote moderate to locally fresh east to southeast trade winds across the local waters. Increasing winds and a long-period northerly swell will result in choppy to rough seas, mainly across the Atlantic waters and portions of the Anegada and Mona Passages. Small Craft Advisories remain in effect at least through tomorrow morning across the passages and through Sunday afternoon across the offshore Atlantic waters. Beach Forecast Issued at 304am AST Sat Dec 13 2025 A long-period northerly swell and increasing wind waves will create life-threatening rip currents along the north and east facing beaches of the islands over the next few days. A Rip Current Statement remains in effect for the northwest to northeast beaches of Puerto Rico, including Culebra, as well as St. Thomas and St. John. Beachgoers are urged to avoid swimming in these conditions, particularly through late tonight. The west and south- facing beaches of the islands will experience a moderate risk of rip currents. For specific location information, please visit weather.gov/beach/sju. .SJU WATCHES/WARNINGS/ADVISORIES... PR...High Rip Current Risk through late tonight for PRZ001-002-005- 008. High Rip Current Risk through this afternoon for PRZ012. VI...High Rip Current Risk until 6am AST early this morning for VIZ001. High Rip Current Risk through this afternoon for VIZ002. AM...Small Craft Advisory until 5pm AST Sunday for AMZ711. Small Craft Advisory until noon AST today for AMZ723. |
San Juan Radar
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