000 AGXX40 KNHC 140736 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 336 AM EDT Mon Aug 14 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... The main feature continues to be the western extension of the Atlantic sub-tropical ridge that reaches across the central Gulf. The associated anticyclonic flow consists of light to gentle winds in the basin. The Yucatan Peninsula thermal trough is in the SW corner, with gentle breezes. The buoys are reporting seas in the 1-3 ft range throughout. A surface trough extends from the Fl Panhandle into the north central Gulf waters. Isolated showers and thunderstorms are over the SE Gulf where a very moist E to SE wind flow is present. The only foreseeable changes will have to do with the pressure gradient tightening in the far western part of the Gulf beginning on Tuesday due to the interaction between deepening low pressure in northern Mexico and W Texas and the ridge that is in place in the Gulf. This is expected to increase the southerly winds in some areas of the western Gulf to the moderate to fresh range, with seas building to around 6 ft in some spots over those areas of the Gulf. These winds are forecast to diminish late on Wednesday as the ridge lifts N to the northern Gulf. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... The latest buoy and available scatterometer data show generally gentle to moderate NE to E trades throughout, except for stronger trades of fresh to strong intensity confined to the far south-central waters S of about 12.5N and between 70W and 74W. The buoys and latest altimeter data indicate seas in the range of 4-6 ft, except for lower seas of 3-4 ft over the western Caribbean, and seas of 2-3 ft over much of the NW Caribbean section. A tropical wave is analyzed just inland the coast of the Yucatan Peninsula and southward ti inland Central America as of 06Z, moving westward at 15-20 kt. This wave will move farther inland through today. A large and well-defined tropical wave currently in the central Atlantic along 57W/58W will across the rest of those waters through this afternoon and across the eastern Caribbean tonight through Tuesday night, the central Caribbean Wednesday and Wednesday night and the western Caribbean Thursday into Thursday night and move inland Central America on Friday. A tightening of the pressure gradient will accompany this wave bringing an increase to the trades across much of the eastern and central Caribbean as it quickly moves across those section of the Caribbean. Expect scattered showers and thunderstorms, some with gusty winds to also accompany the wave and follow in behind it. Yet another large tropical wave will quickly move through the Tropical N Atlantic waters Tuesday night into Wednesday, and move across the eastern Caribbean from about Wednesday afternoon through Thursday night. A NE to SE wind shift of moderate to locally strong winds will accompany this wave. Scattered to numerous showers and thunderstorms with gusty winds are expected as well with this wave. Scattered showers and thunderstorms are rapidly developing in the the SW Caribbean from 11N to 14N and W of 79W, possibly related to the eastern segment of the E Pacific monsoon trough that runs southern Costa Rica to just west of NW Colombia. The presence of speed convergence along the trough is helping to activate this activity. It should remain quite active through the next few days. ...SW N ATLANTIC INCLUDING THE BAHAMAS... The main feature of interest is Tropical Storm Gert. As of 03Z, the center of Gert was located near 28.8N 71.9W moving NNW at 8 kt, with maximum sustained winds 40 kt with gusts to 50 kt. Gert is forecast to gradually intensify as it reaches near 30.0N 72.1W around 12Z this morning, then to near 31.6N 72.1W by early this evening with maximum sustained winds of 55 kt gusts to 65 kt. Gert is forecast to lift N of the forecast waters tonight, and reach near 33.6N 71.2W with maximum sustained winds of 33.6N 71.2W by early on Tuesday. At that time, winds are expected to be less than 20 kt, and seas less than 8 ft over the forecast waters of the N central zone of AMZ 113. Once Gert lifts N of the area, the central Atlantic sub-tropical ridge will build westward along 27N through late on Wednesday before shifting slightly N to near 28N Thursday through Friday night. The northern part of a strong tropical wave, that will be interacting with central Atlantic ridge, is expected to increase winds and seas in the far southeastern waters of the basin, namely to the S of 22N near the Virgin Islands and Puerto Rico, beginning on Wednesday. A slight lull in these is expected on Thursday before they possibly increase significantly late on Thursday and through Friday over the eastern part of zone AMZ 127 as a strong tropical wave or low pressure system begins to cross 55W. Combined seas are expected to build to large heights for with these winds. E winds will pulse to fresh, maybe with brief instances to strong, between the SE Bahamas and Hispaniola in the afternoons and at night beginning tonight. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W... Tropical Storm Warning through this afternoon N of 30N E of 74W. $$ *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 Aguirre. National Hurricane Center.