000 AGXX40 KNHC 200757 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 257 AM EST Mon Nov 20 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 strong cold front crosses the southern Gulf of Mexico from near Marco Island Florida to 21N94W to the southern Bay of Campeche near 18N94W. Surface observations and buoy data indicate winds over the NW Gulf have already begun to subside as high pressure builds over Texas. Satellite-derived wind data from around 04Z confirmed winds to gale force are continuing off the coast of Veracruz Mexico. The front is slowing down and will stall and weaken over the southern Gulf through Tuesday. High pressure over Texas will shift rapidly eastward through the Carolinas by Tue evening, allowing the winds and seas over the Gulf to diminish. A surface trough is expected to develop on Tue over the eastern Gulf as a sharp upper-level trough digs into the lower Mississippi Valley and central Gulf. A reinforcing upper- level disturbance will move into the western Gulf by Wed, causing the trough to deepen into a low pressure area, as well as ushering in another cold front and round of strong northerly winds over the western Gulf late Wed into Thu. Model guidance has come into better agreement on the likelihood of gales off the coast of Mexico during that time frame, so the official forecast calls for a minimal gale force event along the Mexican coast near Veracruz. The low pressure over the eastern Gulf will slowly lift NE across Florida on Thu and allow the front to exit the SE Gulf by Fri night. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... A surface low currently measuring 1008 mb persists over the central Caribbean near 15N73W. Troughing extending NE from the low through the Mona Passage continues to support scattered showers and thunderstorms over the northeast Caribbean and over Puerto Rico and the Dominican Republic to north of the Leeward Islands. Moderate to fresh NE to E prevail over the basin except in the vicinity of the monsoon trough over the SW Caribbean. Winds will diminish over the region as high pressure north of the area weakens in response to developing low pressure along the east coast of the United States. Seas will generally run 2 to 4 ft during the next several days. The weak pressure gradient should remain in place over the Caribbean until Thu, when a cold front will enter the NW Caribbean from the Gulf of Mexico. The front will then stall and weaken over the NW Caribbean Fri. ...SW N ATLANTIC INCLUDING THE BAHAMAS... The latest cold front to enter the area extends SW from 31N72W to near Ft Lauderdale Florida. Fresh to strong SW winds are straddling 30N between the front and 66W. Winds west of the front are fresh. Elsewhere a ridge extends from high pressure over the central Atlantic to east of the central Bahamas near 26N71W, while a weak prefrontal trough crosses the central Bahamas. The pressure gradient along the southern flank of the ridge is generally maintaining moderate winds and 5 to 7 ft seas in NE swell over the forecast waters S of 25N. Winds and seas will increase over the northern Bahamas tonight and Tue as the cold front stalls over the central Bahamas and high pressure builds eastward from the United States east coast. The trough will linger over southeast waters this weekend, then weaken Monday. The front will eventually lift northward through mid week. A second front will move off the NE Florida coast Wed, associated with a low pressure area moving from the eastern Gulf NE across northern Florida to off the Carolinas through Fri. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... .GMZ023...SW GULF S OF 22N W OF 94W... Gale Warning early today. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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.