Anegada Passage Southward to 17N Marine Forecast
| Rest Of Today...Southwest Winds 5 To 10 Knots. Seas 2 To 4 Feet With Occasional Seas Around 5 Feet. Dominant Period 11 Seconds. Isolated Showers. |
| Tonight...West Winds 5 To 10 Knots. Seas 2 To 4 Feet With Occasional Seas Around 5 Feet. Dominant Period 11 Seconds. Isolated Showers. |
| Thursday...West Winds 10 To 15 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 12 Seconds. Isolated Showers. |
| Thursday Night...North Winds 10 To 15 Knots. Seas 6 To 8 Feet With Occasional Seas Up To 10 Feet. Dominant Period 12 Seconds. Scattered Showers. |
| Friday...North Winds 10 To 15 Knots, Becoming Northeast. Seas 5 To 7 Feet With Occasional Seas Up To 9 Feet. Dominant Period 11 Seconds. Isolated Showers. |
| Saturday...Southeast Winds 5 To 10 Knots. Seas 6 To 8 Feet With Occasional Seas Up To 10 Feet. Dominant Period 12 Seconds. Isolated Showers. |
| Sunday...South Winds 5 To 10 Knots, Becoming East. Seas 5 To 7 Feet With Occasional Seas Up To 9 Feet. Dominant Period 14 Seconds. |
| Area Forecast Discussion National Weather Service San Juan PR 218am AST Fri Mar 13 2026 .Short Term(Today through Sunday)... Issued at 158am AST Fri Mar 13 2026 During the overnight hours, clear skies prevailed across western Puerto Rico, while eastern Puerto Rico, Vieques, Culebra, and the U.S. Virgin Islands observed partly cloudy skies as a patch of moisture filtered across the region, increasing the frequency of showers. Nevertheless, rainfall accumulations ranged from 0.10 to 0.30 by 2 AM. Temperatures along coastal areas ranged from the upper 60s to the mid-70s, while interior and mountainous locations cooled into the 60s, similar to previous nights. Winds remained light and variable. Today, an another surge of moisture will continue to move across eastern Puerto Rico during the morning hours, producing periods of showers. This increase in moisture, combined with daytime heating, will promote the development of afternoon convection across the interior and western Puerto Rico, with periods of moderate rainfall, raising the potential for ponding of water on roads and in poorly drained and urban areas. Late today into Saturday, precipitable water values are forecast to decrease to near or below the 25th percentile for this time of year, accompanied by lower mid-level relative humidity and warming temperatures at 500 mb level, resulting in a more stable atmospheric profile and improving weather conditions as a drier air mass prevails across the region. Therefore, expect mostly sunny skies with only brief passing showers across windward areas, mainly during the morning hours, mainly on Saturday. As the day progresses on Saturday, easterly trade winds will strengthen as a high- pressure system builds over the western Atlantic, promoting breezy conditions. On Sunday, precipitable water values are expected to return to near-normal levels as another patch of moisture approaches the region. However, instability is not anticipated. As a result, typical trade-wind showers will affect eastern Puerto Rico and the U.S. Virgin Islands during the overnight and morning hours, followed by isolated afternoon activity across western Puerto Rico. Overall rainfall accumulations are not expected to be significant, as breezy to locally windy conditions will prevail, and conditions will remain seasonable. .Long Term(Monday through Friday)... Issued at 158am AST Fri Mar 13 2026 A broad surface high-pressure system over the western Atlantic will strengthen by early next week, tightening the pressure gradient across the northeastern Caribbean and promoting a steady increase in easterly to east-southeasterly low-level flow beginning Monday and persisting through much of the workweek. Model guidance indicates 925 mb winds increasing well above climatological values, peaking near or above two standard deviations above normal on Monday. As a result, breezy to locally windy conditions are expected, particularly across coastal areas of Puerto Rico, Culebra, Vieques, and the U.S. Virgin Islands, where a limited to locally elevated wind threat may develop and unsecured outdoor items could be blown around or damaged. Although the pressure gradient is expected to relax slightly after Monday, winds will likely remain above normal through the remainder of the forecast period. Mid-level conditions will remain generally stable through the forecast period. Model guidance continues to show 700–500 mb lapse rates below normal to near the lower end of climatological values, while 500 mb temperatures remain near climatological normals. Although a polar trough and its associated frontal boundary are forecast to move off the eastern seaboard early next week, and an upper-level trough may develop northeast of the forecast area toward the end of the period, the local area will remain largely removed from the strongest dynamical forcing. As a result, most of the region will continue to experience marginally stable conditions, limiting deep convective development and favoring mainly shallow trade wind showers. Relative humidity values in the mid-levels will also remain modest, further supporting a generally stable pattern. Moisture levels will remain near climatological normals through most of the period, with precipitable water generally fluctuating between around 1.2 and 1.5 inches. Patches of shallow moisture embedded within the trade wind flow will periodically move across the region, resulting in brief passing showers across windward sectors, particularly during the nighttime and morning hours across eastern Puerto Rico and the U.S. Virgin Islands. During the afternoons, diurnal heating combined with local effects may support the development of isolated to scattered showers across interior and western portions of Puerto Rico. However, the faster steering wind flow will limit the residence time of showers and keep rainfall accumulations generally low. Despite this, ponding of water on roads and in poorly drained areas, along with brief reductions in visibility, can still occur in areas experiencing the heaviest showers. Marine Issued at 158am AST Fri Mar 13 2026 Under a weakening pressure gradient across the northeastern Caribbean, winds will remain gentle to moderate from the east to northeast with seas of 3 to 5 feet. However, a high pressure will build across the northwestern Atlantic late Saturday into early next week will tighten the local pressure gradient and promote increased wind speeds. Fresh to strong trade winds are expected by tomorrow, Saturday, night into early next week, and will result in rough and choppy seas and overall deteriorated marine conditions. Small Craft Advisories will likely be issued later on from late in the weekend into early next week, with seas forecast to build to around 6 to 8 feet. Beach Forecast Issued at 158am AST Fri Mar 13 2026 Today, a moderate risk of rip currents (life-threatening rip currents are possible in the surf zone) will persist for northern beaches of Puerto Rico (from Aguadilla to Fajardo), Culebra, and northern and eastern beaches of St. Croix. Beachgoers should continue to exercise caution. A low risk of rip currents will be present across other exposed beaches of the islands. Even if the risk is low, life-threatening rip currents often occur in the vicinity of groins, jetties, reefs, and piers. A similar pattern will persist through tomorrow, Saturday, night. On Sunday the moderate risk will start to expand to other beaches as breezy conditions start to develop, and by Monday onwards, a high rip current risk will likely be in effect, along with breezy to windy conditions. Beachgoers should continue monitoring the forecast for any updates. For additional information, please visit: weather.gov/beach/sju. Fire Weather Issued at 158am AST Fri Mar 13 2026 Once again, the risk for fire weather treats remains LOW today. Winds will remain light to moderate and RH values are expected to remain above criteria due to the arrival of another patch of moisture across the area. At this time an RFD will not be issued, but we encourage partners to continue monitoring conditions in the coming days, particularly on Saturday as a drier airmass is expected to arrive. .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. |
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