Southern Puerto Rico out 10nm Marine Forecast
|Rest Of Tonight...Northeast Winds 10 To 15 Knots With Gusts Up To 25 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. Dominant Period 6 Seconds. Isolated Showers.|
|Thursday...East Winds 15 To 20 Knots With Gusts Up To 30 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. Dominant Period 7 Seconds. Isolated Showers.|
|Thursday Night...East Winds 15 To 20 Knots With Gusts Up To 30 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. Dominant Period 8 Seconds. Isolated Showers.|
|Friday...East Winds 15 To 20 Knots With Gusts Up To 30 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. Dominant Period 10 Seconds. Isolated Showers.|
|Friday Night...East Winds 15 To 20 Knots With Gusts Up To 30 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. Dominant Period 8 Seconds. Isolated Showers.|
|Saturday...East Winds 15 To 20 Knots With Gusts Up To 30 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. Dominant Period 7 Seconds. Isolated Showers.|
|Sunday...East Winds 15 To 20 Knots With Gusts Up To 30 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. Dominant Period 7 Seconds. Numerous Showers.|
|Monday...East Winds 15 To 20 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 7 Seconds. Isolated Showers.|
| Area Forecast Discussion|
National Weather Service San Juan PR
1020pm AST Wednesday Feb 8 2023
Breezy conditions are expected to prevail across the region overnight. Showers embedded in the trades will move across the northern and eastern half of PR, as well across the USVI. Some showers could move further inland due to the 25 kt ENE steering winds. Ponding of water in roads and in poor drainage areas is possible with this activity. The main threat this week remains the hazardous seas due to the combination of a long period swell and increasing trades.
A northerly swell will build seas between 8 and 12 feet on Thursday. Please refer to the previous discussion below.
/issued 540pm AST Wednesday Feb 8 2023/
SYNOPSIS...Marine and coastal conditions will deteriorate even further by tomorrow due to another northerly swell. Small Craft Advisories, Coastal Flood Advisories, High Surf Advisories, and High Risk of Rip Currents will be in effect by tomorrow due to building seas and hazardous breaking waves. Please refer to the
ction below, as well as the latest Coastal Hazard Forecast (CFWSJU) and Surf Zone Forecast (SRFSJU) for further information. Patches of moist and dry air moving into the region will help promote a variable weather pattern, including passing showers, for the rest of the workweek.
SHORT TERM...Tonight through Friday... Satellite derived precipitable water (PWAT) shows values of around 1.30 mostly across the Mona Channel as well as an air mass with drier values of around or less than an inch approaching from the east and now over most of the local islands. Current model guidance shows this variable pattern persisting through the short term period with areas of more humid and drier air masses filtering in and out of the region. Under breezy northeast winds, any shower activity over the region has started to lull as this drier air mass moves in. Trade wind showers could continue moving inland through windward sections of the islands tonight at times. At surface level, a high pressure system over the western Atlantic continues spreading eastward behind a frontal low. This high pressure system will continue to promote breezy east northeast winds throughout the short term period, while an upper level trough is west of the islands. For tomorrow and through the end of the work week a variable weather pattern will continue as patches of moisture filter into the region bringing shower activity moving inland. Breezy conditions will serve to limit any rainfall accumulations. Current model guidance also does not show much moisture above the lower levels from tomorrow through the end of the short term period. This will result in irregular intervals of shower activity, particularly for the eastern forecast area.
Long TermSaturday through Wednesday
/from Prev Discussion...issued at 424am AST Wednesday Feb 8 2023/
A variable weather pattern will persist for the long-period across all the islands. At the surface, the pattern will be dominated by the Atlantic high pressure generating breezy easterly winds. As usual, the wind pattern will push patches of shallow tropical moisture from time to time. According to the latest model guidance, Saturday and Sunday appear to be the wettest days, with PWAT (Precipitable Water) values up to 1.58 inches, according to the GFS (Global Forecast System) global model. Regardless of the PWAT (Precipitable Water) values, a mid-level ridge promoting a trade wind cap could limit the lifetime of the showers. Unsettled conditions could result, however,from the presence of a strong jet and the "zonal flow" of a shortwave trough at the upper levels. These upper level conditions will induce colder temperatures at 500 MB, decreasing to around minus 9 degrees. Given the expected conditions, on Saturday into Sunday, expect frequent showers in the morning over the U.S. Virgin Islands and eastern Puerto Rico, then slightly stronger over the west in the afternoon. There is a marginal risk for thunderstorms with the heaviest activity; however, it will all depend on the amount of moisture moving through the region.
From Monday onward, a frontal boundary moving out of the eastern seaboard of the United States will induce a more southeasterly wind flow over the region. Just like in previous days, patches of moisture will reach the area at times, turning the skies cloudy with passing showers. Additionally, the south component of the wind will induce slightly warmer temperatures reaching the mid to upper 80s in the coastal regions especially in northern Puerto Rico.
AVIATION...Mainly VFR conditions expected to prevail through the forecast area. Sct SHRA (rain showers) will continue around the lcl waters and NE/SW portions of PR. Breezy conditions will persist, with winds out of the NE at 18-22 kts, with stronger gusts. Winds will subside after 08/23Z, to about 5- 10 kts after 08/23Z. Slightly stronger winds daytime will return after 09/14Z. Maximum winds WSW-W 40-50 kts between FL380-470.
Fresh to locally strong trade winds and northerly swells will continue to promote choppy to rough, and confused, seas across the regional waters throughout the week. A second northerly swell is forecast to arrive and spread across the local waters and passages by late tonight and continue through Sunday, maintaining hazardous and rough seas through the weekend. Small Craft Advisories will be in effect for most coastal waters by late tonight through the end of the week as seas build tomorrow to up to 10 feet, occasionally higher.
A Coastal Flood Advisory will be in effect tomorrow for most of the Atlantic Coastline of Puerto Rico (breaking waves from 14 to 18 feet), Culebra and the northern USVI (breaking waves from 10 to 14 feet). Flooding of lots, parks, and roads with only isolated road closures expected. Dangerous swimming and surfing conditions and localized beach erosion are also expected. A High Surf Advisory will be in effect for these areas as well, along with western beaches of Puerto Rico (breaking waves up to 12 feet) where dangerous swimming conditions and localized beach erosion can be expected. A High Risk of Rip Currents will be in effect for all areas previously mentioned as well as the beaches of St. Croix, and the beaches of SW Puerto Rico and Vieques. Up to 6 ft breaking waves can reach SW Puerto Rico and Vieques by tomorrow afternoon.
Stay tuned to the latest Coastal Hazard Forecast (CFWSJU) and Surf Zone Forecast (SRFSJU) issued by WFO San Juan PR
for further information.
.SJU WATCHES/WARNINGS/ADVISORIES... PR...High Rip Current Risk through Saturday afternoon for PRZ001-002- 005-008-012.
Coastal Flood Advisory from 6am Thursday to 6pm AST Friday for PRZ001-002-005-008-012.
High Surf Advisory from 6am Thursday to 6am AST Saturday for PRZ001-002-005-008-010-012.
High Rip Current Risk from 6am AST Thursday through Saturday afternoon for PRZ010-011-013.
VI...High Rip Current Risk through Saturday afternoon for VIZ001.
Coastal Flood Advisory from 6am Thursday to 6pm AST Friday for VIZ001.
High Surf Advisory from 6am Thursday to 6am AST Saturday for VIZ001.
High Rip Current Risk from 6am AST Thursday through Saturday afternoon for VIZ002.
AM...Small Craft Advisory until 8am AST Sunday for AMZ710-741.
Small Craft Advisory from 2am Thursday to 8am AST Sunday for AMZ712-715-722-732-742.
Small Craft Advisory from 8am Thursday to 8am AST Sunday for AMZ725.