
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 ...CORRECTED National Weather Service San Juan PR 525am AST Wednesday Feb 19 2025 Synopsis The dry trend continues across the islands today, extending the rainfall deficit across the south-central and west PR and under increasing east to southeasterly winds; thus, we expect a high risk of favorable weather conditions for spreading wildfires today across these locations. Additionally, a fading northerly swell and increasing winds will promote a high risk of rip currents, especially along the north-facing beaches of PR and the northern US Virgin Islands. We expect a mix of clear skies, clouds, and limited trade wind showers through the rest of the workweek. However, a surface trough with higher moisture content will shift the forecast to a wetter one by the weekend. Another shower increase is suggested around Monday or Tuesday, with less activity by mid-next week. .SHORT TERM...Today through Friday Overnight weather remained calm, with mostly clear skies over Puerto Rico and the U.S. Virgin Islands. Winds were primarily from the east, maintaining a northeasterly component. Urban and coastal areas experienced temperatures hovering in the 70s, creating a comfortable environment for both locals and visitors. In contrast, mountainous and rural regions were cooler, with temperatures in the 60s. The latest satellite imagery indicates a dominant drier air mass over the local region. Precipitable water models suggest values slowly transitioning from the 25th percentile (below normal) to the 50th percentile (near normal) for this time of year. As a result, little to no rain is expected across the islands today. Winds will gradually shift east-southeast due to the interaction between a surface high-pressure system and a frontal boundary moving westward into the North Atlantic. Maximum temperatures are forecasted to remain in the 80s to low 90s across lower elevations, while higher terrains will experience temperatures in the 70s. These conditions could contribute to a significant fire danger risk, particularly along the southern and western sections of Puerto Rico. Consequently, a Red Flag Warning has been issued for these areas. Therefore, we urge people to be aware of and stay updated on any changes in the forecast today. However, from Thursday into early Friday, increasing moisture will allow precipitable water values to be around 1.6 inches, reaching the 75th percentile. This will result in a higher frequency and intensity of showers. Both ensemble models and local guidance indicate that Thursday will likely be the wettest day of the short- term period. Long Term Saturday through Wednesday A short wave trough will increase instability across the islands by the weekend, promoting diffluence around Monday into Tuesday over the Northeast Caribbean. A jet stream will also move closer to the region by early next week. These factors will result in some instability in the US Virgin Islands and Puerto Rico region, giving place to periods of moderate to locally heavy rains if enough moisture arrives, especially during the maximum diurnal heating. As a frontal boundary lingers north of the islands, a prefrontal trough will promote moisture pooling over or near Puerto Rico and the US Virgin Islands during the weekend, increasing the probability of precipitation across the region. There is a good chance to observe flooding rains on Saturday. Monday through Wednesday, winds will shift mainly from the east- southeast, resulting in warmer temperatures across the islands. Under this wind flow, patches of moisture embedded in the winds will be the primary source of moisture. Low-level convergence will enhance the formation of showers across the windward locations each day. Additionally, sea breeze variations will promote the formation of afternoon showers across the western locations of PR. Model guidance suggests moisture erosion around Wednesday as a mid-level high pressure tries to build over the islands. Marine A fading northerly swell will continue to move across the Atlantic waters. The surface high pressure across the central Atlantic interacting with the frontal boundary over the western Atlantic will promote choppy seas due to moderate to locally fresh east to east- southeast winds across the region during the next few days. A prefrontal trough will increase shower activity by the weekend. Fresh to locally strong winds will deteriorate marine conditions for small craft later this evening. As a result, a Small Craft Advisory is in effect. Beach Forecast Life-threatening rip currents will continue to form along the north-facing beaches in PR and the northern US Virgin Islands due to fading pulses of northerly swells, where a high risk of rip currents is in effect. Additionally, the risk of rip currents is moderate for the rest of the local beaches. Pulses of another northerly swell and increasing winds will increase the risk of rip currents again on Friday. Fire Weather The drying trend continues across the islands, especially across the south-central and western areas of PR, where the rainfall deficits throughout the past 30 days are notable. The hazardous KBDI values at the stations along the southern, southwest, and western locations, combined with increasing east-southeast winds, sea breezes, and strong gusty winds, as well as relative humidity values around the low 40s or lower, will create a dangerous fire weather conditions. Therefore, a Red Flag Warning has been issued due to the high risk of wildfire spreading associated with these conditions. .SJU WATCHES/WARNINGS/ADVISORIES... PR...High Rip Current Risk through this afternoon for PRZ001-002-005- 008-012. Red Flag Warning from 8am this morning to 5pm AST this afternoon for PRZ014-015-018-027. VI...High Rip Current Risk through this afternoon for VIZ001. AM...Small Craft Advisory from 6pm this evening to 6pm AST Thursday for AMZ711. |