000 AGXX40 KNHC 011837 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 137 PM EST Fri Dec 1 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 frontal boundary extends from the western Florida Panhandle to SE of Brownsville near 25N96W. A NW-SE oriented surface trough extends from the NW Gulf near 25N92W to the Yucatan peninsula near 20N90W. Gentle to moderate winds are observed over much of the gulf region, with mainly moderate NE-E winds over the far SE waters. Seas are running between 2 and 4 ft based on buoy observations and the latest satellite-derived sea height data. The frontal boundary will weaken and dissipate during the next day or so as it moves slowly SE. The trough will migrate SW across the western Gulf to the coast of Mexico by Sat evening. High pressure will then build across the area this weekend into early next week. Little change in wind speeds and sea heights are expected through Sun, then marine guidance calls for winds of 15-20 kt and seas building to between 4 and 6 ft by Monday evening, particularly across the SE waters. This will be the result of a tighter pressure gradient between high pressure over the SE United States and a low pressure trough along the coast of Mexico. Southerly return flow will also increase to 15-20 kt across the NW and west-central waters on Mon, ahead of the next cold front forecast to enter the gulf region late on Tue. Fresh to strong notherly winds and building seas are expected in the wake of the front. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... The most recent ASCAT pass indicated the presence of a persistent trough over the western Caribbean that now extends across the Gulf of Honduras to near Cabo Gracias a Dios, Nicaragua. This trough will linger over the far western Caribbean Sea through the weekend and into early next week. A trough over the eastern Caribbean along 64W will remain nearly stationary along 65W/66W over the next few days. A few showers are noted near the trough axis. A recent scatterometer pass shows pretty well the wind shift related to this trough. Moderate to fresh trades are expected over the south-central Caribbean through Sunday, then increase to fresh to strong trades while expanding in coverage Monday through Tuesday. Fresh NE winds to the SW of Cuba will increase to mainly strong winds Sunday night through Tuesday while spreading well southwest over the NW Caribbean waters. Strong NE winds are expected through the Windward Passage Monday night through Tuesday night. These marine conditions will be associated with a high pressure system located N of area that will undergo occasional intensity fluctuations. ...SW N ATLANTIC INCLUDING THE BAHAMAS... Developing 1010 mb low pres is centered over the NE waters near 26N67W. A stationary front extends E from the low to 26N65W to beyond 26N60W. A trough extends SW from the low to the entrance of the Windward Passage. Winds of 20 kt and seas to 9 ft in NE swell are noted within about 90 nm NW semicircle of the low center. The low will quickly move NE to near 29N57W by Sat morning, and to near 31N49W by Sun morning. The associated trough will become a cold front and move across the SE waters during the upcoming weekend. As the low pressure exits the forecast area, high pressure will build E in its wake. This system will generally maintain moderate to locally fresh NE winds over the area through Mon. A tighter pressure gradient will bring and increase of easterly winds over much of the central and southern waters late Mon through Tuesday night. By Tue morning, marine guidance suggests E winds of 20-25 kt and seas of 8-9 ft across the waters E of the Bahamas. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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.