000 AGXX40 KNHC 081833 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 233 PM EDT Thu Jun 8 2017 Marine Weather Discussion for the Gulf of Mexico, Caribbean Sea, and Tropical North Atlantic from 07N to 19N between 55W and 64W and the Southwest North Atlantic including the Bahamas ...GULF OF MEXICO... A surface low is centered over the northeast Gulf waters just west of St. Petersburg, Florida. This feature will continue moving east today across the Florida peninsula and entering the W Atlantic this evening. Its associated cold front extends along 25N and east of 92W. Moderate to fresh winds are within about 90 nm of the low and will diminish as the low crosses Florida. The combination of forcing to the south of the low and a deep moist airmass supports a scattered to numerous showers and thunderstorms over the southeastern Gulf that could produce locally strong winds and seas near 8 ft. As this activity weakens in the afternoon and evening hours, winds and seas will subside. The cold front mentioned above will stall out tonight. High pressure and fair conditions will build over the Gulf behind the front. The front will then transition to a trough on Friday and drift northward across the eastern Gulf over the weekend as high pressure over the western Atlantic expands westward. This weekend pattern will bring with it a return in moisture with scattered showers and thunderstorms over the eastern Gulf, and increasing southeasterly winds to moderate to fresh across the entire Gulf basin. This ridge pattern will then remain in place through early next week. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... Low pressure tracking from the Gulf of Mexico to the Atlantic is weakening the ridging over the western portion of the basin, which will cause winds over the Caribbean and tropical north Atlantic waters to diminish to mainly moderate to fresh today through Saturday. The ridge will build back westward across the western Atlantic Saturday which will bring locally strong trades to the south central Caribbean and Gulf of Honduras starting Saturday night and pulsing each night through at least Monday night. An upper-level trough over the eastern Gulf of Mexico and deep moisture plume are interacting over the northwest Caribbean supporting numerous showers and thunderstorms mainly N of 83N and W of 83W. This activity will continue across this portion of the Caribbean through Friday night, before the trough lifts north as high pressure builds to the west. A tropical wave currently along 72W will enter the western Caribbean tonight, and begin to cross central America on Saturday. This wave will enhance convection along the monsoon trough over the southwestern Caribbean through Friday night. Another tropical wave currently along 53W will enter the tropical Atlantic forecast zones on Friday, then the eastern Caribbean around Saturday. ...SW N ATLANTIC INCLUDING THE BAHAMAS... The pressure gradient between a high pressure from the central Atlantic to Cuba, and low pressures north of 31N continue to support fresh to strong southwest winds and seas to 9 ft mainly north of 29N. Mainly moderate winds prevail elsewhere. Low pressure over the north central Gulf of Mexico will cross into the western Atlantic along 29N-30N today. This will help to increase the wind field east of Florida this evening with southwest winds of 20 to 30 kt forecast to the south of the low. The low will drag a cold front over the northwest waters east of north Florida today, stalling from about 31N74W to 28N81W on Friday. Fresh to strong southwest winds will slide east ahead of the front, mainly north of 28N, while strong northeast winds will nose south of 30N behind the front, east of Florida today and tonight. Seas of 8 to 11 ft can be expected over the waters north of 28N associated with these winds ahead and behind the front today through tonight, with 8 ft or greater seas becoming confined east of the front on Friday. The combination of the southwest surface flow around the periphery of the ridge axis, and deep southwest flow aloft associated with an upper trough to the west, continues to draw abundant moisture across the Bahamas and Florida Straits. This pattern is supporting rounds of heavy rainfall and embedded thunderstorms with frequent lightning. These rounds of precipitation will continue south of the approaching front through the next 24 hours. As the upper-level trough lifts north of the region later on Friday, the coverage of convection will decrease, and become confined near the stalled out frontal boundary. By Saturday, the front will weaken into a trough as it drifts northward, then will become diffuse along about 29N-30N on Sunday. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *For detailed zone descriptions, please visit: http://www.nhc.noaa.gov/abouttafbprod.shtml#OWF Note: gridded marine forecasts are available in the National Digital Forecast Database (NDFD) at: http://www.nhc.noaa.gov/marine/grids.php For additional information, please visit: http://www.nhc.noaa.gov/marine $$ .Forecaster ERA. National Hurricane Center.