000 AGXX40 KNHC 231911 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 211 PM EST Thu Nov 23 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 1012 mb low pressure system is centered over the far NE Gulf near 29N84W. A cold front extends SW from the low to the Bay of Campeche near 18N62W. An amplified trough extending southward from the Mississippi Valley through the Bay of Campeche supports these features. High pressure ridges southward over the western gulf and eastern Mexico from Texas. The pressure gradient between the high pressure and the cold front continues to maintain a large swath of strong to gale force northerly winds over the waters W of the cold front. Surface observations from Coatzacoalcos Veracruz Mexico indicated sustained winds remained above gale force along the Veracruz coast of Mexico, so exceeded all of the model guidance for the wind forecast during the first 6 hours. Used NWPS guidance value of 10 to 13 ft for seas in the gale area. After 12Z expect winds and seas to rapidly diminish as the high pressure ridge shifts rapidly eastward and weakens. Low pressure over the Florida Big Bend will cross northern Florida and reach the SW N Atlantic by this evening and drag the associated cold front across the Yucatan Channel by early Fri morning and across the Straits of Florida by early Saturday morning. Broad but weak high pressure overspreading the Gulf in the wake of the front will maintain gentle to moderate winds through Sat night. Seas across the basin are expected to subside to between 2 and 4 ft by Sun morning, when a weak cold front will introduce more cold air to the NW Gulf. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... A persistent surface trough crosses the western Caribbean along 82W from western Cuba to Costa Rica. Isolated thunderstorms are noted near this feature. The trough is forecast to be nudged eastward during the next couple of days as a cold front enters the NW Caribbean from the Gulf of Mexico. Another much weaker surface trough crosses the far eastern Caribbean from near St Lucia to the Virgin Islands near 18N64W. This trough possesses no significant convection. Low pressure systems currently near Florida and Bermuda have weakened the ridge to the north. As a result, gentle to moderate trades and seas of 3 to 5 ft prevail over the Caribbean. The cold front forecast to enter the NW Caribbean will do so by early Fri morning, then reach from western Cuba to Belize by Fri evening. The front will dissipate after it reaches from central Cuba to the Gulf of Honduras on Sat evening while dissipating. The pressure gradient between building high pressure over Central America and the frontal boundary will cause northerly winds of 20 to 25 kt to funnel along the Nicaragua coast tonight through Monday night. Seas are expected to peak around 8 ft on Monday night. ...SW N ATLANTIC INCLUDING THE BAHAMAS... Deepening low pressure is centered just NE of the forecast zones near 31.5N64.5W. This system will continue to pull away toward the NE during the next couple of days. Winds and seas in Zone 115 will subside below advisory levels this evening. Another low pressure system, currently over the far NE Gulf of Mexico, will move across northern Florida today and reach the SW N Atlantic by this evening. The associated cold front will enter the NW Bahamas on Sat night, enter the central Bahamas early Sunday morning, then finally cross the SE waters Sunday night and Monday morning as it weakens to a frontal trough. Showers and thunderstorms could produce gusty winds in the vicinity of the low and cold front. Model guidance suggests that a reinforcing surge of cold air following the front will reach the north waters by Sun evening and move southward through Mon night. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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 McElroy. National Hurricane Center.