Marine Weather Net

Northern US Virgin Islands and Culebra Marine Forecast


REST OF TODAY

W
WINDS
5 - 10
KNOTS

TONIGHT

W
WINDS
10 - 15
KNOTS

THURSDAY

NW
WINDS
10 - 15
KNOTS

THURSDAY NIGHT

N
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
AMZ715 Forecast Issued: 929 AM AST Wed Mar 08 2023

Rest Of Today...West 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 10 To 15 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 10 Seconds.
Thursday...Northwest Winds 10 To 15 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 11 Seconds. Numerous 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. Seas 6 To 8 Feet With Occasional Seas Up To 10 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 6 To 8 Feet With Occasional Seas Up To 10 Feet. Dominant Period 14 Seconds.
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Area Forecast Discussion
National Weather Service San Juan PR
416pm AST Tuesday May 28 2024

Synopsis
Expect, marginally unstable weather conditions to persist across the region through the next several days. An east-southeasterly wind flow will continue to bring plenty of tropical moisture from the warmer Caribbean waters, enhancing the potential for strong showers and thunderstorms over the interior and northwestern Puerto Rico each afternoon.A relatively drier airmass is expected to filter into the region by the end of the workweek, promoting stable weather conditions and warm to hot temperatures.

.SHORT TERM...Tonight through Thursday... Today, the weather conditions played an important role across Puerto Rico and the U.S. Virgin Islands. A combination of hazy skies, warm weather, and periods of rainfall prevailed. Light showers filtered across the eastern half of Puerto Rico and the island of Saint Thomas during the morning hours, and by the late morning, showers developed along the San Juan metro areas and over the interior municipalities, leaving around an inch of rain. The typical afternoon convection developed over the northwestern sections of Puerto Rico, where the concentrations ranged above an inch of rain. Temperature-wise, they remained in the upper 80s to low 90s along the coastal and urban areas, while over the higher elevations, they stayed in the 80s. These high temperatures, combined with the available moisture, allowed the heat indices to be above 112 degrees Fahrenheit along the northern coast of Puerto Rico, where the
Excessive Heat Warning...s in effect. The remaining coastal areas of Puerto Rico, Culebra, Vieques, and the U.S. Virgin Islands stayed with the Heat Advisory. Overall, all the islands experienced hot conditions. Like in previous days, the prevailing wind flow was out of the east-southeast.

Overnight, expect variably cloudy skies across the region. The eastern sections of Puerto Rico and the island of Saint Thomas should experience some showers as patches of moisture move across the area from time to time. The temperatures will range in the upper 60s to low 70s across higher elevations to the lower 80s along the coastal areas. Wind-wise, they should stay generally light and variable, influenced by land breezes.

Weather conditions will gradually transition to a more typical seasonal shower pattern, driven by diurnal heating and local effects, with enhanced afternoon convective development over the interior and west to northwestern Puerto Rico each day. Afternoon convection is also possible elsewhere. We foresee limited to elevated flooding risks in urban areas, roads, small streams, and washes, particularly over the northwestern PR during the afternoon.

As mentioned in previous discussions, despite persistent cloud cover and high rain probabilities, warmer-than-normal conditions will continue. Coastal and urban areas are expected to have lows in the lower 80s, while higher elevations may see lows around 70 degrees. In contrast, highs will range from the lower 90s in lower elevations to the upper 70s in higher elevations. With ample moisture present, heat indices may exceed 108 degrees Fahrenheit in many coastal and urban areas, with some locations experiencing brief periods of 112 degrees or higher.These warm conditions pose a significant health risk, prompting the issuance of Excessive Heat Warnings/Advisories. Regarding the hazy skies, expect them to continue as some particles of Saharan Dust and dry air filter across the islands from time to time. Residents and visitors should take necessary precautions, particularly those engaging in outdoor activities.

Long Term
Friday through Tuesday... //from previous discussion//

A mid-to-upper level ridge moving from the south-southeast into the local area will promote relatively drier weather conditions and warmer temperatures. Nonetheless, light wind flow from the southeast in combination with daytime heating and local effects will enhance showers and thunderstorm development across the northwestern portions of Puerto Rico each afternoon. Despite of the presence of the ridge, tropical moisture being pulled from the warm Caribbean Waters will approach the local area by late Saturday. The latest Precipitable Water Content Analysis suggest values from 1.9 to 2.45 through the period. Due to the expected conditions, there is a limited to elevated risk of urban and small stream flooding and isolated flash flooding mainly for central, northern and northwestern Puerto Rico. By Sunday into Tuesday a weak surface trough is forecast to develop west of our area, increasing once again the potential for moderate to heavy rainfall across the islands. Warmer temperatures are expected to persist through the entire period with values between the upper 80s to low 90s along the coastal and urban areas of the islands. Heat indices are likely to surpass the mid 100s, resulting in excessive heat conditions for the islands.

Marine
A moderate east to southeast wind flow will prevail across the region over the next few days. Showers and isolated thunderstorms associated with the trailing moisture of a departing tropical wave and a surface trough east of us will continue to affect the regional waters and local passages. So far, the next tropical wave, located in the central tropical Atlantic near 50W, is forecast to approach the regional waters by mid-week, with its bulk of moisture well to the south across the Caribbean Sea.

Beach Forecast

There is a low risk of rip currents across all beaches of Puerto Rico and the U.S. Virgin Islands tonight. Moderate to heavy showers and isolated thunderstorms are possible each afternoon mainly across the northwestern waters of Puerto Rico.

.SJU WATCHES/WARNINGS/ADVISORIES... PR...

Excessive Heat Warning...til 6pm AST Wednesday for PRZ001-005- 008.
Heat Advisory until 6pm AST Wednesday for PRZ002-003-007- 010>013.

VI...
Heat Advisory until 6pm AST Wednesday for VIZ001-002.

AM...None.