000 AGXX40 KNHC 041848 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 148 PM EST Mon Dec 4 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 ----------------------------------------------------------------- PREVIOUS DISCUSSION... ...GULF OF MEXICO... A strong cold front will enter the northwestern Gulf Tuesday night. A weak low pressure is expected to develop along the front near south Texas, which will push the western part of the front southward and drag the eastern part slowly across the remainder of the basin through Friday. Winds should reach gale force over portions of the west-central and southwestern waters Thursday and Friday with the GEFS showing a peak of about 50 percent chance of local gales in the extreme west-central Gulf. The GEFS also shows about a 30 percent chance of gales over the central Gulf on Thursday. Peak seas should reach 8' by late Tuesday night over the northwesternmost Gulf and quickly spread southeastward. 12' seas are likely to occur in the central and western Gulf from Thursday morning until late Friday night with a peak close to 18' in the extreme western and southwestern Gulf. The timing of the frontal passage over the eastern Gulf of Mexico, in particular, is uncertain with the 12Z GFS showing a Friday afternoon crossing of South Florida, while the 12Z UK and ECMWF indicating about 24 hours later. Unclear at this lead time which is correct, so taking a blend of these solutions for the forecast. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... Tradewinds will remain at fresh to strong breeze in the central Caribbean through Thursday before diminishing Friday. These will produce seas of 8 to 11' through Thursday. Winds are quiescent elsewhere, though seas up to 8' may affect the offshore Windward Island zones due to easterly swell from trades on Wednesday. Large northerly swell from a gale-force-strength winter low in the Central Atlantic will begin affecting the offshore waters for the entire Lesser Antilles starting on Thursday. Combined seas from these northerly swell along with easterly swell from tradewinds will reach up to 11' seas on Friday and Saturday. A cold front will reach the northwestern Caribbean on Friday night or Saturday. The timing of the event is uncertain with the 12Z GFS suggesting as early as Friday night while the 12Z UKMET and ECMWF indicate a Saturday afternoon crossing. Regardless of the timing, the northerly winds behind the front are projected to be near gale conditions with a gale be possible across the Yucatan Channel. ...SW N ATLANTIC INCLUDING THE BAHAMAS... A stationary front north of Hispaniola and Puerto Rico will become diffuse by Wednesday. Building high pressure along 70W will support fresh to strong trades north of the Greater Antilles through Wednesday. These will cause peak seas of up to 10' just east of the central Bahamas, southeastern Bahamas, and the Turks and Caicos. A weak cold front will reach the Atlantic just east of northeast Florida Wednesday night, but not progress much and remain stationary through Saturday. Winds and seas from this front will not be significant. Moderate northeasterly swell up to 10' will reach the eastern zones beginning on Thursday. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... .GMZ013...N CENTRAL GULF INCLUDING FLOWER GARDEN BANKS MARINE SANCTUARY... GALE CONDITIONS POSSIBLE Thu. .GMZ017...W CENTRAL GULF FROM 22N TO 26N W OF 94W... GALE CONDITIONS POSSIBLE Thu night. .GMZ019...CENTRAL GULF FROM 22N TO 26N BETWEEN 87W AND 94W... GALE CONDITIONS POSSIBLE Thu. GALE CONDITIONS POSSIBLE Fri. .GMZ023...SW GULF S OF 22N W OF 94W... GALE CONDITIONS POSSIBLE Thu night into Fri. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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 Landsea. National Hurricane Center.