000 AGXX40 KNHC 181720 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 120 PM EDT Thu May 18 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 ridge extends from the western Atlantic from Bermuda to the Carolinas, then across the Gulf coast states through central Texas. Moderate to fresh southerly flow dominates the basin, except locally strong through the Straits of Florida, and gentle in the northeast Gulf where the gradient is weaker. Seas are 4 to 6 ft across most of the Gulf, except up to 8 ft through the Straits of Florida, and 2 to 4 ft in the northeast Gulf. Winds will pulse locally to fresh to strong northwest of the Yucatan peninsula each evening with the typical thermal trough developing each afternoon just inland. Winds will also pulse to fresh to strong through the Straits of Florida during the next couple of evenings, as a weakening surface trough moves across Florida into the eastern Gulf. Otherwise, ridging will hold just north of the area through the weekend with moderate to fresh east to southeast flow prevailing. Southerly flow over the northwest Gulf will diminish by late Sunday as a weak cold front moves off the Texas coast. The front will stall over the northwest Gulf through early Monday, then lift north of the area and become stationary along the northern Gulf coast through Tuesday. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... A sharp upper trough reaching from the northern Bahamas to off the east coast of Nicaragua continues to support an area of showers and thunderstorms across the west-central Caribbean, now propagating southward between Colombia and Jamaica. While this is farther south of where earlier heavy rainfall occurred, impacting Haiti and Jamaica, further development cannot be ruled out over the islands through tonight. A tight gradient between the subtropical ridge north of the area and the trough is supporting fresh to strong trade winds across the central Caribbean. The ridge will build north of the eastern Caribbean and tropical north Atlantic west of 55W as the trough moves slowly west through Saturday. This will be in phase with the westward exit of a weak tropical wave farther S in the deep tropics. These shifts will allow the area of fresh to strong winds to expand into the southern Caribbean and slightly more west, with fresh to strong trade winds and seas to 9 ft between Colombia and Jamaica by Friday. Meanwhile, northeast to east swell to 8 ft will propagate into the tropical north Atlantic waters east of the Windward Islands by Friday. ...SW N ATLANTIC INCLUDING THE BAHAMAS... A surface trough extends from the Cay Sal area of the Bahamas through western Cuba and into the northwest Caribbean, while ridging extends along 32N anchored by a high center near Bermuda. Fresh to locally strong winds are blowing from north of Hispaniola and offshore of northern Cuba through the Straits of Florida, with moderate to locally fresh east to southeast flow elsewhere. The pressure gradient will relax a little by Saturday after the trough moves well W of the region. A weak cold front over the southeast United States will approach the northeast Florida coast by early next week, with little impact on winds or seas anticipated so far. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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 Christensen. National Hurricane Center.