000 AGXX40 KNHC 131902 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 302 PM EDT Sun Aug 13 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 extends westward 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. Widely scattered moderate to isolated strong precipitation is within 90 nm of the southern end of the trough. 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 6 or 7 ft in some spots over those areas of the 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 along 85W S of western Cuba at 12Z moving westward 20 kt. This wave will move across the rest of the western Caribbean through this afternoon, and inland central America tonight. A large and well-defined tropical wave currently in the central Atlantic along 53W/54w S of 20N is expected to begin to move across the eastern portion of the Tropical N Atlantic waters this evening, then move across the rest of those waters through tonight, and across the eastern Caribbean Monday through Tuesday night, the central Caribbean Wednesday and Wednesday night and the western Caribbean Thursday into Thursday night. A tightening of the pressure gradient will accompany this wave bringing an increase to the trades across much of the eastern and central Caribbean Monday through Thursday. 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 move quickly 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. Isolated to widely scattered rainshowers and thunderstorms are in the the SW Caribbean from 17N southward from 76W westward, 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 now Tropical Depression Eight that formed late last night. As of 15Z, the center of Tropical Depression Eight was located near 27.4N 71.5W moving NNW 11 kt, with maximum sustained winds 30 kt with gusts to 40 kt. The depression is forecast to intensify to a tropical storm near 29.1N 72.2W this evening with maximum sustained winds 35 kt gusts to 45 kt...reach near 30.7N 72.4W tomorrow morning with maximum sustained winds 40 kt gusts to 50 kt. It is forecast to move just to the north of the area on Monday night, near 32.5N 71.9W with 45 kt gusts 55 kt. High pressure will build westward along 27N through Thu, after the tropical storm exits the forecast area. 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, S of 22N near the Virgin Islands and Puerto Rico, beginning on Wednesday. E winds will pulse to fresh to strong between the SE Bahamas and Hispaniola in the afternoons and at night beginning on Monday night. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W... Tropical Storm Warning tonight into Mon. $$ *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.