921 AXNT20 KNHC 100000 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 800 PM EDT Thu Aug 9 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...SPECIAL FEATURES... ...Post-Tropical Cyclone Debby... The center of Debby, at 09/2100 UTC, is near 45.5N 40.5W. The estimated minimum central pressure is 1004 mb. Debby is moving NE or 55 degrees, at 20 knots. The maximum sustained wind speeds are 35 knots with gusts to 45 knots. Widely scattered moderate to isolated strong rainshowers are from 42N to 44N between 42W and 45W. Debby is expected to continue moving northeastward while weakening. Debby is forecast to dissipate by 10/0600 UTC. Please read the last NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 25W from 20N southward, moving W 15 knots, across the Cabo Verde Islands. This wave is associated with a 700 mb trough. Scattered moderate convection is from 08N to 11N between 23W and 30W. An Atlantic Ocean tropical wave is along 40W from 12N southward, moving W 15 knots. This is a low amplitue and low latitude wave. Widely scattered moderate convection from 08N to 10N between 36W and 45W. An Atlantic Ocean tropical wave is along 58W from 18N southward, moving W 20 knots. A well-defined inverted V surface pattern is apparent in satellite imagery. Scattered showers are within 120 nm of the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Mauritania near 17N16W, to 12N24W, 10N31W, and 09N37W. The ITCZ continues from 09N39W to 08N50W. Besides the convection mentioned in the tropical wave section, scattered moderate convection is from 08N-11N between 30W-35W. ...DISCUSSION... GULF OF MEXICO... A weak surface ridge extends from central Florida near 28N82W, southwestward into the central Gulf of Mexico, toward the SW corner of the Gulf of Mexico. An upper level cyclonic circulation center is near 27N84W, in the SE corner of the Gulf of Mexico. Upper level cyclonic wind flow covers the Gulf of Mexico from 90W eastward. Isolated moderate rainshowers cover the area from 25N northward, and from 83W eastward to include Florida. An upper level cyclonic circulation center is in interior Mexico near 20N101W. Isolated moderate rainshowers are in the waters W of 90W. A surface trough will develop in the Yucatan Peninsula from the early evenings to overnight hours during the next several days. The surface trough will be accompanied by a surge of fresh to occasionally strong winds. A surface ridge will prevail elsewhere across the area into early next week. The ridge will support moderate to fresh SE flow in the west central Gulf of Mexico, and off the coast of Texas early next week. CARIBBEAN SEA... Upper level cyclonic wind flow covers the E Caribbean Sea from 16N northward between SE Cuba and 60W. An upper level trough passes through 22N67W in the Atlantic Ocean, to 16N66W in the Caribbean Sea. The monsoon trough is along 09N73W in Colombia, through NW Panama, and beyond southern Costa Rica, into the eastern Pacific Ocean. Scattered moderate to isolated strong convection is from 07N-11N between 75W-86W. Surface high pressure that is to the north of the area will support fresh to strong winds in the south central Caribbean Sea through early next week. One tropical wave will approach the Windward Islands and the Leeward Islands tonight, moving through the central Caribbean Sea by Sunday, and west of the region early next week. A second tropical wave will move into the eastern Caribbean Sea and the central Caribbean Sea on Monday. The winds will approach approach minimal gale force again on Sunday night NW of the Coast of Colombia as the pressure gradient tightens temporarily. ATLANTIC OCEAN... Debby is in the north-central Atlantic Ocean. Please read the SPECIAL FEATURES section for details. An upper level trough extends from Bermuda to 22N67W to 16N66W in the Caribbean Sea. Isolated moderate rainshowers are from 20N northward between 60W and 70W. An upper level trough extends from a 34N50W cyclonic circulation center to 30N51W and 27N58W. Isolated moderate to locally strong rainshowers are within 60 nm to 90 nm on either side of the line that runs from 28N59W to 29N52W beyond 32N48W. A surface trough passes through 33N74W to 31N77W. Isolated moderate rainshowers are from 27N northward from 70W westward. A surface ridge extends from a 1030 mb high pressure center that is near 38N22W, through 32N36W, to 28N49W, to 28N74W, to Florida near 28N81W. Surface anticyclonic wind flow spans the Atlantic Ocean from 20N northward between Africa and the eastern coast of the U.S.A. The current 28N surface ridge will shift southward to 25N tonight. The ridge will be to the east of a trough, that will be moving off the southeastern coast of the U.S.A. through Friday. The ridge then will move N to 28N through Monday. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa