566 AXNT20 KNHC 170451 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1251 AM EDT Fri Aug 17 2018 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0430 UTC. ...SPECIAL FEATURES... The center of Tropical Storm Ernesto at 17/0300 UTC is near 44.1N 38.9W, or 1145 km/620 nmi to the E of Cape Race in Newfoundland, 1205 km/650 nmi to the NW of the Azores. Ernesto is moving NE, or 55 degrees, 19 knots. The estimated minimum central pressure is 1007 mb. The maximum sustained wind speeds are 40 knots with gusts to 50 knots. Scattered moderate to isolated strong rainshowers cover the waters from 42N to 46N between 36W and 40W. Please read the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT5/WTNT35 KNHC for more details. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 26W/27W from 17N southward. Rainshowers are possible within 360 nm on either side of the tropical wave. An Atlantic Ocean tropical wave is along 52W/53W from 20N southward. Isolated moderate to locally strong rainshowers are from 07N to 15N between 50W and 60W. Some development of this system is possible during the next couple of days, while the tropical wave moves west-northwestward 15 mph toward the Windward Islands. Unfavorable environmental conditions should limit the chances for additional development, while the system moves across the eastern Caribbean Sea by late Saturday. It is likely that this system may bring locally heavy rainfall to parts of the Lesser Antilles on Friday and Saturday. A Caribbean Sea tropical wave is along 68W/69W from 20N southward. Isolated moderate rainshowers cover the Caribbean Sea from the Greater Antilles southward between 60W and 73W. A tropical wave is along 90W/91W, at the western edge of the Yucatan Peninsula, from 22N southward. Warming cloud top temperatures and weakening convective precipitation, and lingering widely scattered moderate to isolated strong rainshowers are in the Gulf of Mexico and the coastal plains of the western part of the Yucatan Peninsula from 21N southward between land and 93W. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Guinea- Bissau near 11N16W, to 09N23W, and 09N33W. The ITCZ continues from 09N33W to 12N42W, and 12N49W. Precipitation: Isolated moderate to locally strong rainshowers are elsewhere from 06N to 15N from 50W eastward. ...DISCUSSION... GULF OF MEXICO... Upper level cyclonic wind flow covers the SW corner of the Gulf of Mexico from 23N southward from the Yucatan Channel westward. Warming cloud top temperatures and weakening convective precipitation, and lingering widely scattered moderate to isolated strong rainshowers are in the Gulf of Mexico and the coastal plains of the western part of the Yucatan Peninsula from 21N southward between land and 93W. A surface ridge extends from a 1025 mb high pressure center that is near 31N69W, across Florida just to the north of Lake Okeechobee, into the east central Gulf of Mexico, to the coast of Mexico along 20N in the SW corner of the Gulf of Mexico. Isolated moderate to locally strong rainshowers are in the waters from 23N northward from 90W eastward. An east-to-west oriented surface ridge extends across the Gulf waters along 28N. The ridge is accompanied by gentle to moderate anticyclonic wind flow, that is expected to increase to a fresh southerly breeze across the northwest waters, from Sunday night through early Monday. A surface trough will develop along the Yucatan Peninsula during the late afternoons, then drift westward across the SW Gulf waters during the overnight hours. The trough will be accompanied by a fresh east-to-southeast wind shift, with the trough dissipating along 96W during the late mornings. CARIBBEAN SEA... Isolated moderate to locally strong rainshowers cover the NW corner of the Caribbean Sea, from 14N northward from 79W westward. Upper level anticyclonic wind flow covers the Caribbean Sea from the Windward Passage westward. Nocturnal near gale force easterly trade winds are expected along the northwest coast of Colombia overnight, and then again on Friday night. A tropical wave along 68W will continue westward across the central Caribbean tonight, and pass through the western Caribbean waters during the upcoming weekend. A second tropical wave will reach along 55W on Friday, and pass through the eastern Caribbean Sea on Saturday and Sunday. The tropical wave will be accompanied by locally strong rainshowers through early Saturday. ATLANTIC OCEAN... An upper level trough passes through 32N37W, to 27N44W, to an Atlantic Ocean cyclonic circulation center that is near 25N53W. A surface trough is along 32N55W 28N57W 25N60W. Isolated moderate to locally strong rainshowers are from 30N northward between 44W and 57W. Rainshowers are possible elsewhere from 20N northward between 30W and 60W. Surface anticyclonic wind flow is on either side of the 32N55W-to-25N60W surface trough. Broad upper level cyclonic wind flow, and isolated moderate rainshowers, cover the Atlantic Ocean from the Greater Antilles northward from 60W westward. A few individual cyclonic circulation centers near 27N63W, and near 21N70W. An east to west ridge extends from 30N65W to 28N81W. Light southerly winds are to the north of the ridge. Fresh trade winds are to the south 23N, except becoming locally strong along the north coast of Hispaniola during the late afternoon into early evening hours. For additional information please visit http://www.hurricanes.gov/marine $$ MT