000 AGXX40 KNHC 210752 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 252 AM EST Tue Nov 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 trough is analyzed on the 0600 UTC surface map across the gulf waters and extends from 28N86W to 23N90W to 20N94W. Some shower activity is noted along the trough axis. This trough is the reflection of a sharp upper-level trough extending from SE Louisiana to near Tuxpan, Mexico. 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. Strong northerly winds and building seas will follow the front. Winds will further increase to gale force in the wake of the front, across the SW gulf by mid-day Wed and persist to Wed night. Seas are forecast to build up to 12 or 13 ft within the area of gale force winds. The low pressure over the eastern Gulf will slowly lift NE across Florida on Thu and allow the cold front to exit the SE Gulf by Thu night. At that time, mainly gentle to moderate northerly winds are expected across the gulf waters with seas of 6-8 ft S of 22N and 3-6 ft elsewhere. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... The most recent scatterometer pass indicated fresh to strong NE winds across the Windward Passage and downstream to near the northern coast of Jamaica. Fresh trade winds are noted near the coast of NW Venezuela and northern Colombia, with gentle to moderate winds elsewhere. A trough persists across the central Caribbean and extends from 18N76W to to 15N78W to 11N78W. A few showers are near the trough axis, forecast to meander across the west-central Caribbean over the next 48-72 hours. Winds will diminish over the region as high pressure north of the area weakens in response to the 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. Building high pressure over Central America, in the wake of the front, will bring an increase in winds within 90-120 nm off the coast of Nicaragua Thu night through Sat. During that time frame, marine guidance suggests N winds of 20-25 kt and building seas of 6-7 ft. ...SW N ATLANTIC INCLUDING THE BAHAMAS... A cold front extends from 31N57W to 29N61W, where it becomes stationary and continues SW to SE Florida. Fresh to strong NE-E winds are noted in the wake of the front per scatterometer data. Moderate to fresh winds are also seen ahead of the front affecting the SE Bahamas, Turks and Caicos Islands, and regional waters including the approaches to the Windward Passage, and the Old Bahama Channel between the Bahamas and eastern Cuba. A pre- frontal trough extends from 28N62W to 22N68W. A couple of ship observations, as well as buoy 41046, indicate fresh to strong NE winds between the front and the trough. A belt of fresh to strong winds will persist N of the front today, with seas building to 9-10 ft across the waters N of 27N. By tonight, winds will remain strong and veer to the SE as the front lifts northward through mid week. A second cold front will move across the north forecast waters on Wed, followed by another cold front moving off the NE Florida coast by late Thu. This front will be associated with a low pressure area forecast to move NE from the eastern Gulf across northern Florida to off the Carolinas by Fri. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... .GMZ023...SW GULF S OF 22N W OF 94W... Gale Warning Wed into Wed night. GALE CONDITIONS POSSIBLE Wed night into Thu. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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.