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. |
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Area Forecast Discussion National Weather Service San Juan PR 456am AST Monday Dec 2 2024 Synopsis The east to east-southeast wind flow will promote a mixture of sunshine and clouds with above normal heat index values through at least the middle of the week, when a cold front should moves closer to the islands promoting a somewhat relief in local air temperatures. Showers embedded in the winds will bring occasional periods of moderate to locally heavy rain at times each day. The frequency and intensity of showers will increase around Tuesday and Thursday with the proximity of the frontal boundary and a short wave trough aloft. Instability will increase by Monday next week, as a TUTT-low swing by the region. .SHORT TERM...Today through Wednesday... Overnight, calm weather conditions prevailed across Puerto Rico and the U.S. Virgin Islands. Pockets of moisture and showers, embedded in the trade winds, dominated the Atlantic and Caribbean waters, and some of these showers filtered across the eastern sections of Puerto Rico, Vieques, Culebra, and the U.S. Virgin Islands. However, rainfall accumulations were minimal, staying below 0.30 inches. Coastal and urban temperatures remained in the upper 70s to low 80s, while mountain areas experienced temperatures in the upper 60s to low 70s. The latest model guidance continues to suggest a surface high- pressure system extending from the Northeast to the Central Atlantic, with a frontal boundary stretching from Cuba to the Central Atlantic, too. This pattern will result in east- southeasterly winds. Therefore, residents and visitors can expect variable weather conditions each day, including early morning showers across the U.S. Virgin Islands, Vieques, Culebra, and the eastern half of Puerto Rico. Afternoon showers and a few thunderstorms are expected, particularly in the western sections of Puerto Rico and local waters during the overnight hours. At this time, it does not look like the frontal boundary will cross our area but will linger off to the north-northwest of the region, enhancing moisture pooling over the Northeast-Caribbean, increasing the likelihood of more frequent showers, especially on Tuesday. A short-wave trough aloft is expected to weaken the ridge pattern, which will slightly increase the chance of stronger afternoon convection on Tuesday, as well. Overall, we anticipate a gradual increase in precipitable water values from today onward, with the best instability expected across the region on Tuesday and a slight improvement in weather conditions on Wednesday as the winds gradually shift to the east-northeast. Temperatures are not going to be as hot as during the summer. However, heat indices will continue to range from normal to slightly above normal for this time of the year, especially across the urban/coastal areas of PR and the USVI. Long Term Thursday through Monday... A short wave trough moving eastward across the Atlantic will weaken the ridge aloft, establishing a zonal flow Thursday into early Friday. The mid-high pressure will build again from Friday onward, drying out the mid-levels and promoting subsidence throughout the weekend. Additionally, thermodynamic and stability parameters do not look favorable for organized convection during the long-term forecast. TUTT-low will follow the ridge aloft early next week, increasing the atmospheric instability over PR and the USVI. On Thursday, a frontal boundary/shear line extending from Haiti into the Central Atlantic will favor moisture pooling over/near the islands of PR/USVI. Depending on its location, a pre-frontal trough will enhance shower activity across or near the local islands. Considering all these factors, Thursday looks wet. Another cold front, exiting the US Eastern Seaboard, will approach the region from the Western Atlantic. This weather pattern will promote the return of the trade winds, promoting a relief in the local temperatures during the second part of the week. However, the expected amount of cooling in the air temperatures will be subject to the sea surface temperature, which, regardless of the current cooling observed in comparison with the previous months, the sea surface anomalies are still between one and two degrees Celsius above normal for this time of the year. In terms of precipitation, we anticipate a tropical winter advective pattern, as pockets of moisture embedded in the trades will promote occasional passing showers across the windward sections early morning and night. Periods of sunshine and clear skies will be present Friday through Sunday, but afternoon convection cannot be ruled out across western PR, mainly due to local effects and sea breeze variations. Although widespread flooding is not expected, some of these showers will result in periods of moderate to locally heavy rains. Also, one or two thunderstorms will develop daily across the local waters, especially during the afternoon or night hours. The TUTT-low forecast to move closer to the islands next week, could promote favorable atmospheric conditions for the observation of organized convection next Monday. Marine The interaction between a frontal boundary extending from the Caribbean into the Central Atlantic and a surface high pressure over the central Atlantic will promote moderate to locally fresh east to east-southeast winds. Confused seas will continue due to moderate chops to choppy seas and a fading northerly swell. Therefore, small craft operators should exercise caution. The remnants of a cold front will move closer to the islands by the middle of the week, promoting an increase in shower and thunderstorm formation. Beach Forecast Beachgoers, life-threatening rip currents will develop along the Atlantic Coastline of PR, the northern US Virgin Islands, and the eastern half of St Croix, where the risk of rip current is moderate. Additionally, life-threatening rip currents often occur in the vicinity of groins, jetties, reefs, and piers. Exercise caution and stay tuned for the evolution of the surf zone beach forecast. .SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None. |
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