000 AGXX40 KNHC 141855 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 255 PM 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 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 in 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... A large and well-defined tropical wave currently is along 60W/61W. It will move across the eastern Caribbean islands during the rest of today, and through the eastern Caribbean tonight through Tuesday night, through the central Caribbean Wednesday and Wednesday night, through the western Caribbean Thursday into Thursday night, and then 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 moves quickly across those sections of the Caribbean. Expect scattered showers and thunderstorms, some with gusty winds, to accompany the wave also and follow behind it. Yet another large tropical wave will move quickly through the Tropical N Atlantic waters, from Tuesday night into Wednesday, move across the eastern Caribbean from about Wednesday afternoon through Thursday night, and across the central Caribbean Friday and Friday 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 also with this wave. Scattered showers and thunderstorms are in the SW Caribbean, from 10N to 12N between 81W and 84W in eastern Nicaragua, 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 during the next few days. ...SW N ATLANTIC INCLUDING THE BAHAMAS... The main feature of interest is Tropical Storm Gert. The 15z center position is 30.3N 72.2W, moving N 7 kt, with maximum sustained winds 50 kt with gusts to 60 kt. Gert is forecast to intensify gradually, around sunset, near 31.5N 72.2W, 55 knots with gusts 65 knots. Gert is forecast to be to the north of the area around sunrise on Tuesday morning, near 33.4N 71.3W, with maximum sustained wind speeds 60 knots and gusts to 75 knots. 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, at that same time. 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, once Gert lifts N of the area. The northern part of a strong tropical wave, that will be interacting with central Atlantic ridge, is expected to increase the winds and sea heights 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 winds and seas is expected on Thursday before they possibly increase significantly late on Thursday and through Friday in 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. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W... Tropical Storm Warning today into tonight. $$ *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 MT. National Hurricane Center.