635 AXNT20 KNHC 041204 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 804 AM EDT Sat Aug 4 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 1130 UTC. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 20W from 17N southward. isolated moderate to locally strong rainshowers are in the area that is from 10N to 14N between 20W and 24W. An Atlantic Ocean tropical wave is along 26W/27W from 17N southward. isolated moderate rainshowers are in the area that is from 08N to 14N between 25W and 30W. An Atlantic Ocean tropical wave is along 53W/54W from 19N southward. widely scattered moderate to isolated strong rainshowers are from 10N to 1N between 55W and 60W. A Caribbean Sea tropical wave is along 68W/69W from 20N southward, moving W 10 to 15 knots. isolated moderate rainshowers are in the area that is from 10N to 17N between 60W and 71W. A Caribbean Sea tropical wave is along 84W/85W from 202N southward, moving W 10 to 15 knots. The wave is moving into the area of a pre-existing upper level cyclonic wind flow, with a trough. A tropical wave is along 94W/95W from 20N southward, from the SW corner of the Gulf of Mexico into the eastern Pacific Ocean. rainshowers are possible within 60 nm to 120 nm on either side of the tropical wave. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Senegal and Gambia near near 13N17W, to 12N21W, 12N25W, and 11N32W. The ITCZ continues from 11N32W to 08N43W, 07N48W, and 07N56W. Precipitation: widely scattered moderate to isolated strong rainshowers are from 08N to 13N between Africa and 31W. isolated moderate rainshowers are from 03N to 16N between 31W and 60W. Please refer to the TROPICAL WAVES section for more information about precipitation. ...DISCUSSION... GULF OF MEXICO... Upper level cyclonic wind flow from a trough spans the NW corner of the Gulf of Mexico, the Texas coastal waters, and interior sections of Mexico from 20N northward from the Texas Big Bend eastward. The upper level trough was being associated with a stationary front during the last few days. The southwesternmost point of the stationary front now is in west central Louisiana. One surface trough is in the northeast and north central Gulf of Mexico, from the Florida Panhandle to SE Louisiana, and to 26N93W. A second surface trough is along 28N95W 25N96W 20N97W. widely scattered moderate to isolated strong rainshowers cover the Gulf of Mexico to the west of the line from 30N86W 24N90W 19N92W. Upper level cyclonic wind flow covers the Gulf of Mexico from 87W eastward. The cyclonic wind flow is related to the upper level trough that extends from the NW Bahamas to coastal Nicaragua. widely scattered moderate to isolated strong rainshowers cover the Straits of Florida, parts of Cuba, and the Caribbean Sea to the south of Cuba from 18N to 25N between 74W and 85W, and in the Gulf of Mexico from 24N northward between 83W and 87W. The northern part of a tropical wave will cross the southern Gulf this weekend. Surface troughs moving W from the Yucatan Peninsula will produce fresh to locally strong winds over the eastern waters of the Bay of Campeche from sunset to around midnight. Otherwise, high pressure ridging will prevail in the wake of the tropical wave. CARIBBEAN SEA... An upper level trough extends from the NW Bahamas, across the western half of Cuba, into the coastal sections of Nicaragua. Scattered to numerous strong rainshowers are in the coastal areas of Nicaragua from 11N to 14N between 82W and 85W. widely scattered moderate to isolated strong rainshowers cover the Straits of Florida, parts of Cuba, and the Caribbean Sea to the south of Cuba from 18N to 25N between 74W and 85W, and in the Gulf of Mexico from 24N northward between 83W and 87W. isolated moderate rainshowers are elsewhere from 10N to 15N between 78W and 81W. Isolated moderate rainshowers are from 14N to 16N between 68W and 74W, in an area of scattered to broken low level clouds. An upper level trough extends from an Atlantic Ocean 21N56W cyclonic circulation center, to 15N59W, toward Venezuela and Trinidad. A tropical wave is moving through the same area. The monsoon trough is along 08N/09N between 74W in Colombia and beyond 83W/84W in southern Costa Rica. Isolated moderate rainshowers are elsewhere in the SW corner of the Caribbean Sea, away from the Nicaragua precipitation, from 11N southward from 76W westward. Fresh to locally strong trade winds are expected in the central Caribbean Sea and in the Gulf of Honduras through Wednesday night. The strongest wind speeds will pulse to 30 knots near 12N74W during the overnight hours, and the sea heights may reach 10 to 12 feet. It is possible that the wind speeds may approach minimal gale force near the coast of Colombia late on Wednesday night. ATLANTIC OCEAN... Upper level cyclonic wind flow and comparatively drier air in subsidence cover the Atlantic Ocean from 20N northward between 66W and 73W. Large-scale cyclonic wind flow covers the Atlantic Ocean from 20N northward between 20W and 60W. The comparatively greatest amount of cyclonic wind flow is associated with a cyclonic circulation center that is near 37N40W. A cold front passes through 32N36W to 30N40W and 32N45W. A stationary front continues northwestward to a 1016 mb low pressure center that is near 35N50W. A cold front continues from the low pressure center, through 32N55W, to 31N60W, to Bermuda, and to 34N67W. Scattered moderate to strong rainshowers are from 30N to 32N between 45W and 47W. Isolated moderate rainshowers are elsewhere from 24N northward between 40W and 52W, and from 30N northward between 50W and 70W. . The wind speeds will pulse to strong speeds near the northern coast of Hispaniola each night through Wednesday night. The trade trade winds, elsewhere across the region, will diminish gradually through early next week. An Atlantic Ocean ridge will weaken, with a backdoor cold front moving southward. The front will weaken into a trough by Sunday evening. It is possible that weak low pressure may develop along the trough through early next week. A surface ridge will re-develop by the middle of the next week as the trough dissipates. For additional information please visit http://www.hurricanes.gov/marine $$ MT