000 AXNT20 KNHC 310002 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 802 PM EDT Wed Aug 30 2017 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... Tropical Depression Harvey is centered near 31.2N 92.6W at 31/0000 UTC or about 9 nm SW of Alexandria Louisiana, moving NNE at 7 kt. Estimated minimum central pressure is 998 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Rain is noted on radar over SE Texas and W Louisiana from 30N-34N between 91W- 95W. Scattered moderate convection is observed further E, over the NE Gulf of Mexico, the Florida Panhandle , and S Alabama, from 28N- 33N between 86W-89W. Catastrophic flooding is still expected over southeast Texas and southwest Louisiana. See the latest Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT4/WTNT34 KNHC and the full Forecast/Advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details. T.S. Irma is centered near 16.4N 31.2W at 30/2100 UTC or about 417 nm W of the Cabo Verde Islands, moving W at 13 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Scattered moderate convection is from 14N-20N between 28W-34W. See the latest Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT1/WTNT31 KNHC and the full Forecast/Advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC for more details. ...TROPICAL WAVES... A tropical wave over the central Atlantic extends from 24N48W to 09N49W, moving west at 15 kt. The wave coincides with an amplified 700 mb trough in initial model wind fields. TPW satellite imagery shows an area of modest deep layer moisture. Satellite imagery also shows an area of Saharan dust to the west of the wave. No convection is observed within this wave at this time. A tropical wave over the central Caribbean extends from 22N73W to 08N75W, moving west at 10 kt. The wave coincides with modest 700 mb troughing in initial model wind fields and curvature of low- level winds in scatterometer data. SSMI TPW imagery shows this wave is embedded in an area of modest deep layer moisture. Scattered moderate convection is over E Cuba and Haiti. Scattered moderate to isolated strong convection is along the coast of N Colombia from 09N-14N between 72W-81W. A tropical wave over the western Caribbean extends from 21N86W to 09N86W, moving west at 10 to 15 kt. The wave coincides with subtle 700 mb troughing in initial model wind fields. TPW satellite imagery shows this wave is embedded in an area of modest deep layer moisture. Scattered moderate to isolated strong convection is inland from the Yucatan Peninsula to S Nicaragua. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from 14N17W to 18N25W. The monsoon trough continues W of Irma from 14N34W to 11N40W to 11N48W. The ITCZ continues from 11N48W to 10N51W to 09N61W. Besides the convection associated with Irma, scattered moderate convection is from 06N-09N between 33W-38W. Similar convection is over the the Windward Islands from 09N-13N between 57W-65W due to the ITCZ. ...DISCUSSION... GULF OF MEXICO... Tropical Depression Harvey is centered over Louisiana. A feeder band is over the NE Gulf and the Florida Panhandle with convection. Please see above. The tail end of a stationary front is over N Florida from 29N80W to 31N86W. Scattered moderate convection is N of the front over S Georgia. Further S, scattered moderate convection is over W Cuba. An area of scattered showers has developed over the Bay of Campeche south of 23N and west of 93W. Harvey is expected to slowly weaken and reach NW Mississippi by Thursday evening. Little change is expected across the remainder of the basin. CARIBBEAN SEA... Two tropical waves are moving across the Caribbean waters. See the Tropical Waves section above for additional details. The eastern portion of the E Pacific monsoon trough passes over the southwest Caribbean along 10N. Low-level convergence near the trough is producing scattered moderate convection over Costa Rica and Panama. An area of scattered moderate convection is moving across the Windward Islands. This activity will continue moving west affecting the southeast Caribbean waters through the next 24 hours. Scatterometer data depicts moderate to fresh trades across the basin. ...HISPANIOLA... Scattered moderate convection is presently over Haiti due to a tropical wave. Expect gradual clearing as the tropical wave moves well W of the island. ATLANTIC OCEAN... T.S. Irma is over the eastern Atlantic, while a tropical wave is moving over the central Atlantic. Refer to the sections above for details about these features. A surface trough extends from 31N43W to 27N44W with scattered moderate convection. The remainder of the basin is under the influence of a surface ridge anchored by a 1027 mb high centered over the Azores near 38N27W, and a 1018 mb high centered near 26N59W. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa