000 AGXX40 KNHC 200709 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 209 AM EST TUE DEC 20 2016 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... MODEL PREFERENCE: Global model blend. High confidence. Strong high pressure from the central United States to northern Mexico continues to support up to a 40 kt gale over the southwestern Gulf south of 23N, to the west of a stationary front that extends from 29N82W to 25N92W to 18N91W. This gale is forecast to continue through early this afternoon, before the high begins to gradually weaken, allowing for winds over the southwestern Gulf to decrease below gale force. A recent altimeter pass showed seas around 20 ft offshore Veracruz, prompting an increase in forecast wave heights over the gale area through much of this morning. Clusters of thunderstorms persist over the Bay of Campeche due to low level convergence. This convergence enhanced precipitation is forecast to continue until this afternoon. Elsewhere north of the front, fresh to strong northerly winds continue, with the strongest winds over the western Gulf. Moderate to fresh northeasterly winds are south of the front. The high north and west of the front will gradually weaken, while slowly sliding eastward through Thursday. This will cause the stationary front over the central and western Gulf to slowly decay, while the eastern portion drifts southeastward, becoming oriented from central Florida to the central Gulf by tonight. The entire front should dissipate by Thursday afternoon. Another cold front is forecast to enter the northwestern Gulf Wednesday night, and stall out from northern Florida to near Veracruz Mexico on Friday. High pressure behind this front will not be as strong as the current ridge, with winds currently forecast to peak near 25 kt over the southwestern Gulf Thursday night. This second front should dissipate late Friday, with return flow then developing over the entire Gulf basin over the upcoming weekend. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: Global model blend. High confidence. Strong high pressure north of the region and climatologically lower pressures over Colombia continue to force the gale that is occurring over the waters to the north of the Colombia coast. This pressure gradient also supports fresh to strong trades over the remainder of the Caribbean basin, except the far northwest corner, which is resulting in seas of 8 to 13 ft over the open waters of all portions of the Caribbean except for the northwest portion. This general pattern is forecast to continue the next two days, except with a decrease in intensity of winds of about 5 kt over the region later this morning as the high to the north weakens slightly. This weakening of the high will result in winds decreasing to below gale force later this morning, with mainly fresh to locally strong winds then forecast to prevail over the Caribbean from this afternoon through the remainder of the work week. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: Global model blend. High confidence. A stationary front over the northwest zone AMZ111 will linger through today, then transition to a cold front as high pressure slides eastward toward the east coast of the United States. This front will gradually dissipate as it crosses the northern zones through Thursday. Scattered showers and thunderstorms will continue to be possible within about 100 nm of this frontal boundary. Fresh northerly winds and seas around 7 ft will be possible north of the front to our northern border of 30N through today. A ridge axis that extends from Bermuda to central Florida is supporting fresh to strong northeast winds along, south, and east of the central Bahamas, including the Windward Passage and our southeastern zones. Seas of 8 ft can be expected around the Windward Passage. Seas of 8 to 11 ft can be found east of the Bahamas to beyond 65W. The ridge axis will weaken slightly through today which will allow the winds to relax below 20 kt over this area. However, easterly swell of 8 ft or greater may continue east of the central and southern Bahamas through Wednesday night. Later this week, the pressure pattern breaks down and mainly gentle to moderate surface winds will prevail, except fresh northeast winds near the Windward Passage. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... .GMZ023...SW GULF S OF 22N W OF 94W... Gale Warning early today into this afternoon. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ031...CARIBBEAN FROM 11N TO 15N BETWEEN 72W AND 80W INCLUDING COLOMBIA BASIN... Gale Warning early today. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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 Latto. National Hurricane Center.