000 AGXX40 KNHC 210710 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 310 AM EDT Fri Apr 21 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 few showers and thunderstorms are noted over the SE Gulf in association with an upper-level low spinning over the south- central waters. A surface trough is analyzed across this area and extends from 24N84W into the Yucatan Channel and the western Caribbean. The trough is forecast to persist over the SE Gulf over the next 48-72 hours. A low pressure may briefly develop along the trough axis over the SE Gulf on Saturday, and move across Florida on Sunday. The latest observations indicate mainly moderate E to SE flow across the basin around weak high pressure located in the NE Gulf, except E of the above mentioned trough, including also the Straits of Florida, where fresh easterly winds are noted per the most recent scatterometer pass. Seas are mainly 2-4 ft across the area, except 4-6 ft across the SE Gulf and the Straits of Florida, and 1-3 ft in the SW Gulf. A ridge will continue to dominate the Gulf region today. Expect moderate to fresh southerly return flow across the NW Gulf late today ahead of a cold front forecast to enter the NW Gulf by Saturday afternoon. Fresh to strong northerly winds are expected behind the front, with seas building to 6-8 ft by Sunday morning. The front will extend from the Florida Panhandle to near Tampico, Mexico by Sunday morning, then from Tampa Bay, Florida to the northern Yucatan Peninsula Monday morning, pushing SE of the Gulf Monday night. A reinforcing trough or cold front may move through the N central and NE Gulf Monday night into early Tuesday. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... As previously mentioned, a trough extends across the SE Gulf of Mexico into the western Caribbean to the Gulf of Honduras. A relatively tight pressure gradient between the trough and high pressure located near 32N70W is supporting fresh easterly winds across the Straits of Florida, in the lee of west and central Cuba, and across the Windward Passage. Today, mainly moderate to locally fresh trades will prevail with seas of 4-6 ft, particularly across the central and NW Caribean. Seas will subside to 2-3 ft across the NW Caribean later on Saturday, with 4-5 ft prevailing elsewhere. Fairly tranquil marine conditions will prevail across the western half of the basin the remainder of the upcoming weekend. A weakening cold front may slip SE of the Yucatan Channel Monday night with little impact. Moderate to fresh trades will prevail across the eastern half of the basin as well as across the tropical N ATLC through the next several days. Seas will be mainly 2-4 ft W of 72W and 4-6 ft E of 72W. Seas will subside to 4-5 ft in the tropical N ATLC tonight through Saturday, with northerly swell building seas back to 5-7 ft Sunday into next week. ...SW N ATLANTIC INCLUDING THE BAHAMAS... A 1022 mb high pressure located near 32N70W extends a ridge across the forecast waters. Under the influence of this system, moderate to fresh winds are noted south of 23N, with gentle to moderate anticyclonic winds elsewhere around the high center, along with 3-5 ft seas. The high pressure will sink south into the weekend with a NW to SE ridge prevailing across the waters. Moderate to fresh E-SE will prevail across the SW half of the basin with gentle to moderate winds elsewhere. Seas will be pulsing to 4-7 ft across the waters outside of the Bahamas through the next several days as additional pulses of northerly swell propagates through the area. Southerly winds will increase to 15-20 kt off NE Florida by late Sunday ahead of a cold front approaching from the W. The front is forecast to enter the forecast region by late Sunday night, and extend from 31N75W to west-central Cuba by Monday night. Southerly winds ahead of the front will further increase to 20-30 kt across the forecast zones AMZ113 and AMZ115 Monday through Tuesday, with building seas of 8-11 ft. This will be the result of a tight pressure gradient between front and a high pressure center located east of the forecast area. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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 GR. National Hurricane Center.