Marine Weather Net

Anegada Passage Southward to 17N Marine Forecast


REST OF TODAY

SW
WINDS
5 - 10
KNOTS

TONIGHT

W
WINDS
5 - 10
KNOTS

THURSDAY

W
WINDS
10 - 15
KNOTS

THURSDAY NIGHT

N
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
AMZ722 Forecast Issued: 929 AM AST Wed Mar 08 2023

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
433pm AST Sunday April 21 2024

Synopsis
An unsettled weather pattern is expected to continue through Monday as a moisture field continue to move into the area from the Caribbean. Saharan dust is forecast to arrive on Tuesday, promoting hazy skies. A wet and unstable weather pattern will return by mid-week and prevailing though the rest of the week.

.SHORT TERM...Tonight through Tuesday... Light to moderate showers has been observed across much of the region today. However, locally heavy shower activity was observed over St. Croix and the southwestern portions of Puerto Rico. Doppler radar estimated rainfall accumulations of 1.0 inch in St. Croix, and between 1.0 to 2.5 inches between Guayanilla to San German. Daytime temperatures were observed in the low to mid 80s across the lower elevations, and in the upper 70s along the higher elevations. Winds were from the northeast at 10 to 15 mph.

Plenty of moisture moving into the area from the Caribbean waters, will promote the development of shower activity during the overnight hours across the U.S. Virgin Islands and the eastern portions of Puerto Rico. As a surface high pressure migrates towards the northeast Atlantic winds will shift from the southeast. However, an unsettled weather pattern will persist until mid-week as the moisture field continues to filter in from the southeast Caribbean. Showers are expected mainly across St. Croix and the eastern portions of Puerto Rico during the morning hours. Then, the shower activity and isolated thunderstorms will focus across the interior, northern, and northwestern portions of Puerto Rico. Due to the expected activity, there is an elevated risk of flooding of urban areas, small streams, washes, and mudslides.

Conditions are expected to gradually improve on Tuesday. Although, showers and isolated thunderstorms are anticipated each afternoon over the Cordillera Central and western Puerto Rico. Saharan dust is expected to arrive on Tuesday, with the main concentration of dust staying south of the islands over the Caribbean Sea. Therefore, hazy skies are expected across the islands, with reduced visibilities at times.

Long Term
Wednesday through Sunday... /Issued 450am AST April 21 2024/

Traces of suspended Saharan dust particulates will still be present on Wednesday, leading to some hazy skies, especially during the morning hours. For the rest of the week, a wet and unstable weather pattern will persist. A series of short-wave troughs will move over the local islands throughout the week, creating favorable dynamical conditions aloft for shower and deep convective development. This will maintain 500 mb temperatures between -6 and -7 degrees Celsius and steep lapse rates for most of the long-term forecast. Meanwhile, elevated moisture levels will be present at all levels, with columnar moisture well above normal for this time of year.

Most indicators, including precipitable water and the GDI (Galvez- Davidson Index), suggest that Friday will have the highest chance of thunderstorms and heavier showers. This is when low-level moisture convergence and steep lapse rates will be at their maximum. Friday also poses the greatest potential for widespread urban and small stream flooding, as well as localized flash flooding, although similar risks will also exist on previous days with less areal coverage. As mentioned earlier, river streamflows will remain elevated, especially those across interior Puerto Rico. Therefore, any additional rainfall could lead to quick river rises in these areas. Additionally, saturated soils will enhance runoff, increasing the risk of landslides in steep terrain.

Weather conditions will gradually improve by the weekend. However, lingering moisture, coupled with diurnal heating and local effects, will continue to foster afternoon convection across interior portions of Puerto Rico and downwind of the smaller islands.

Marine
A surface high pressure north of the area will continue to yield a moderate northeasterly wind flow through at least Monday. Winds are expected to become from the east southeast on Tuesday as a surface trough prevails across the northeast Caribbean. Showers and isolated thunderstorms will continue to affect the local waters from time to time.

.SJU WATCHES/WARNINGS/ADVISORIES... PR...None. VI...None. AM...None.