Southern US Virgin Islands, Vieques and Eastern Puerto Rico out 10nm Marine Forecast
|Rest Of Today...Southwest Winds 5 To 10 Knots. Seas 1 To 3 Feet. Dominant Period 11 Seconds. Isolated Showers.
|Tonight...West Winds 5 To 10 Knots. Seas 1 To 3 Feet. Dominant Period 10 Seconds. Isolated Showers.
|Thursday...West Winds 5 To 10 Knots. Seas 2 To 4 Feet With Occasional Seas Around 5 Feet. Dominant Period 10 Seconds. Numerous Showers.
|Thursday Night...North Winds 10 To 15 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. Dominant Period 11 Seconds. Scattered Showers.
|Friday...North Winds 10 To 15 Knots With Gusts Up To 25 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 11 Seconds. Isolated Showers.
|Saturday...Southeast Winds 5 To 10 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 12 Seconds. Isolated Showers.
|Sunday...South Winds 5 To 10 Knots, Becoming East. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 12 Seconds.
| Area Forecast Discussion
National Weather Service San Juan PR
451am AST Fri Feb 23 2024
Weak mid to upper ridge will replace a departing upper trough which will continue to lift north and east of the region, while a surface high pressure ridge builds across the southwest Atlantic and north of the area. This will create a west to northwest wind flow aloft and light to moderate northerly winds in the low levels today, then becoming more easterly by Saturday and Sunday with the approach of an induced surface trough from the east. In the meantime a dry and stable airmass will prevail today into early Saturday with increasing moisture and unstable weather expected once again by late Saturday and the rest of the upcoming weekend. Cool and pleasant seasonal temperatures with light surface winds, and sea/land breeze variations are forecast for today and into the weekend.
.SHORT TERM...Today Through Sunday... Mainly fair and dry weather conditions were observed across the islands during the overnight hours. Winds prevailed from the north at 5 to 10 mph. Overnight temperatures were seen in the upper 50s to low 60s across the higher elevations and in the mid 60s to low 70s across the coastal and urban areas.
After the passage of a cold front across the region, a mass of dry and stable air mass will dominate local weather today into tomorrow Saturday. At this moment, rainfall is not anticipated across Puerto Rico and the U.S. Virgin Islands. However, passing showers over the waters cannot be ruled out. Northerly winds will prevail today, shifting from the east-northeast later tonight. Cooler temperatures are forecast today with daytime temperatures reaching the low 80s along the coastal and urban areas, into the 70s across the higher elevations.
A moist airmass associated to the remnants of the cold front will approach the area from the southeast by late Saturday into Sunday. The latest Precipitable Water content Analysis (PWAT), show increasing values from 1.30 to 1.60 inches. With the available moisture, there is an increase in the chance of showers across the U.S. Virgin Islands and eastern Puerto Rico during the morning hours, followed by afternoon convective activity across portions of central and western Puerto Rico. Another cold front, that is forecast to move off the eastern coast of the Continental U.S. today, is expected to approach the local area by late Sunday into Monday. Therefore, there is a potential for wetting rains by the beginning of the upcoming workweek.
Monday through Friday... Pooling of moisture associated with the return remnants of an old frontal boundary and an induced surface trough will merge with another cold frontal boundary and lift across the region through Wednesday. This will again bring an increase in low to mid level moisture convergence and instability aloft as a short wave polar trough is forecast to sweep across the region. Consequently, enhanced showers with a slight chance for isolated thunderstorms will be possible at least through early Wednesday. Light to moderate east northeast winds will prevail through Monday then becoming more easterly by Tuesday. As the winds shift to a more easterly component, shower activity should then be focused mainly the eastern portions of Puerto Rico and the U.S. Virgin Islands during the morning hours, followed by afternoon convection mainly across the central interior and west to northwestern Puerto Rico. Periods of isolated to scattered showers can also be expected in and around the U.S. Virgin Islands during that time. Ponding of water on roads and in poor drainage areas as well as minor urban flooding will remain possible through at least early Wednesday. By late Wednesday and through the rest of the period, a gradual erosion of moisture is expected with improving conditions and diminishing cloud cover and shower activity, as a strong high pressure ridge will build aloft. This along with a surface high pressure ridge which will move into the southwest Atlantic and build across the region will result in a northeast wind flow and stable conditions once again. However, occasional patches of trade wind moisture may reach portions of the islands from time to time and this will aid in the development of early morning showers and mostly isolated to scattered afternoon showers. Significant rainfall accumulations are not anticipated during the latter part of the period. So far the wettest period with excessive rainfall impacts should be between Monday through early Wednesday morning followed by a drying trend and lesser convection thereafter.
During the period, seasonal temperatures are expected to persist across Puerto Rico and the U.S. Virgin Islands. Overnight temperatures will drop into the low to mid 60s in the higher elevations and valleys, and from the upper 60s to low 70s in the coastal areas. Daytime highs will range from the mid 80s across the coastal and urban areas, to the upper 70s to low 80s in the higher elevations.
Only a few passing showers are possible at times over the regional waters but mostly fair weather skies will prevail today into Saturday. High pressure building across the southwest Atlantic and an area of low pressure well northeast of the region will aid in maintaining light to moderate north to northeast winds today and into the weekend.
For beachgoers, there will be a High Risk of Rip Currents for northern Puerto Rico from Aguada to Carolina today due to a northwesterly swell with breaking waves up to 7 feet possible. There is a moderate risk for the remaining north facing beaches including the northern USVI and a low risk for the southern coastal beaches including the islands of St Croix.
.SJU WATCHES/WARNINGS/ADVISORIES... PR...High Rip Current Risk from 6am AST this morning through late tonight for PRZ001-005-008.