617 AXNT20 KNHC 131204 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 804 AM EDT Mon Aug 13 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 0600 UTC surface analysis and satellite imagery through 1145 UTC. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 23W/24W, from 20N southward, moving west 10-15 kt. Scattered moderate convection is in the monsoon trough area. It is possible that any precipitation may be more related to the monsoon trough than to just the tropical wave. An Atlantic Ocean tropical wave is along 43W/44W from 21N southward, moving west 10-15 kt. This wave is depicted in model diagnostics and 700 mb streamline analysis, and TPW imagery shows moderate moisture in its vicinity. Isolated moderate to locally strong rainshowers are from 10N to 13N between 40W and 43W. An Atlantic Ocean tropical wave is along 56W/57W from 21N southward, moving west 15-20 kt. This wave is also depicted in model diagnostics. It is possible that any precipitation may be more related to the monsoon trough than to just the tropical wave. A Caribbean Sea tropical wave is along 74W/75W from 22N southward, moving west 15-20 kt. Scattered moderate to strong rainshowers are between Jamaica and SE Cuba. It is possible that this precipitation may be more related to the current upper level cyclonic wind flow than to just the tropical wave. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of NW Mauritania near 21N17W, to 16N21W 10N26W and 10N40W. The ITCZ is along 08N between 45W and 55W. Widely scattered moderate to isolated strong rainshowers are from 07N to 11N between land and 22W, and from 04N to 10N between 26W and 38W, and from 07N to 11N between 47W and 63W. ...DISCUSSION... GULF OF MEXICO... A surface ridge prevails across the basin, anchored by a 1018 mb high centered near 28N88W. With this, a gentle to moderate anticyclonic flow prevails across the area. To the southwest, a surface trough extends over the Bay of Campeche from 23N93W to 19N92W. A nocturnal trough will develop during the evening hours in the Yucatan Peninsula before pushing offshore into the SW Gulf each night. A surge of fresh to occasionally strong NE to E winds will accompany this trough. It will become weaker by mid-week. High pressure, elsewhere, generally will support light to moderate E to SE winds in the remainder of the basin through Friday night. CARIBBEAN SEA... An upper-level low is centered near 21N80W. This feature is enhancing convection across the northwest Caribbean waters mainly north of 18W and west of 79W, including western Cuba. A tropical wave is along 72W. The monsoon trough extends along 10N between 76W- 82W. Scattered showers are in Panama and Costa Rica. High pressure north of the area will maintain fresh to strong winds in the south central Caribbean Sea through Tuesday. Strong to minimal gale force winds are expected along the coast of Colombia and Gulf of Venezuela through early this morning. Winds and seas in the Caribbean Sea will subside during mid-week as the western Atlantic Ocean high pressure weakens slightly. ATLANTIC OCEAN... An upper level low is centered in the northwestern Caribbean Sea near 21N80W. This feature is also enhancing convection across the western Atlantic Ocean, mainly across the Bahamas. Three tropical waves are moving across the basin. The remainder of the basin is under the influence of a surface ridge, anchored by a 1026 mb high centered near 31N61W and another 1026 mb high near 34N35W. The surface ridge will remain in place during the next several days. This ridge will help to maintain fresh to locally strong winds along the northern coast of Hispaniola and in the approaches to the Windward Passage, during the evening and nighttime hours. Gentle to moderate anticyclonic wind flow will continue N of 23N, while mainly moderate easterly wind flow will prevail S of 23N. For additional information please visit http://www.hurricanes.gov/marine $$ era/mt