000 AXNT20 KNHC 301154 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 754 AM 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 0600 UTC surface analysis and satellite imagery through 1100 UTC. ...SPECIAL FEATURES... Tropical Storm Harvey is centered near 30.2N 93.6W at 30/1200 UTC or about 22 nm WNW of Lake Charles Louisiana, Texas moving N at 8 kt. Estimated minimum central pressure is 992 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Associated deep convection is sheared to the NNW of the center over the extreme NE Texas and extreme SW Louisiana coasts near the Sabine River. Convergent low-level flow southeast of the center is still producing a band of scattered moderate and isolated strong convection over the north central Gulf within 30 nm either side of a line from Mobile Alabama to 24N91.5W. Coastal areas of far SE Louisiana, Mississippi, Alabama and the western Florida panhandle are also included in this area. See 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. A tropical wave is over the E Atlantic associated with a 1009 mb low that is located near 16N27W. The wave axis extends from 23N26W to the low to 09N27W, moving W at 10-15 kt. Numerous moderate and scattered strong convection is found from 14N to 18N between 27W and 32W. Scattered moderate convection is occurring elsewhere from 11N to 20N between 25W and 34W. A recent scatterometer pass indicated 20-25 KT winds within 360 nm in the NE semicircle of the low. The wave is embedded in an area of deep layer moisture as seen on TPW satellite imagery. This system has become better organized since yesterday, and a tropical depression could form from this system over the eastern Atlantic during the next couple of days. There is a high chance for this system to become a tropical cyclone during the next 48 hours. ...TROPICAL WAVES... A tropical wave over the central Atlantic has an axis extending from 24N44W to 10N43W, moving W around 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 located on the east side of the wave. Satellite imagery also shows an area of Saharan dust to the E and W of the wave. Scattered moderate and isolated strong convection is present from 08N to 10N between 42W and 48W. A tropical wave over the E Caribbean extends from 24N70W to 10N73W moving W around 10 kt. The wave coincides with modest 700 mb troughing in initial model wind fields and curvature of low- level winds in a 0115Z scatterometer pass. SSMI TPW imagery shows this wave is embedded in an area of modest deep layer moisture. This wave is triggering isolated thunderstorms over Hispaniola and adjacent waters to the south to 14N. A tropical wave over the W Caribbean extends from 21N85W to 09N85W, moving W 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. This wave is producing isolated thunderstorms along the east coast of Nicaragua. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from Mauritania on the African coast near 20N16W to 17N21W to low pres 1008 mb centered near 16N27W to 10N50W. The ITCZ continues from 10N50W to 09N60W. Besides the convection associated with the tropical waves, scattered moderate convection is from 06N to 09N between 34W and 40W and from 10N to 13N between 54W and 62W, to include portions of the Windward Islands. ...DISCUSSION... GULF OF MEXICO... Tropical Storm Harvey has a low-level exposed center located over extreme SW Louisiana near 30N93W. Associated deep convection is sheared to the NNW of the center over the extreme NE Texas and extreme SW Louisiana coasts near the Sabine River. Convergent low-level flow southeast of the center is still producing a band of scattered moderate and isolated strong convection over the north central Gulf within 30 nm either side of a line from Mobile Alabama to 24N91.5W. Coastal areas of far SE Louisiana, Mississippi, Alabama and the western Florida panhandle are also included in this area. Catastrophic inland flooding is forecast to continue over Texas and Louisiana in the wake of record setting rains during the next few days. An upper-level trough extends southward through Oklahoma and Texas. Divergent upper level winds east of the trough axis are aiding convection over the Gulf of Mexico and Florida N of 26N. Harvey is moving slowly NE and has just made landfall over extreme SW Louisiana. Harvey is expected to slowly weaken and reach NE Louisiana Thursday morning. CARIBBEAN SEA... Two tropical waves are moving across the Caribbean waters. See the tropical waves section for additional details. The eastern portion of the E Pacific monsoon trough passes over the SW Caribbean along 10N. Low-level convergence near the trough is producing scattered moderate and isolated strong convection along the coasts of Colombia and Panama south of 10N. In the upper levels, an upper level low centered over the Yucatan Peninsula near 22N89W is enhancing showers over the Yucatan and Central America. ...HISPANIOLA... Isolated showers and thunderstorms are occurring over the island due to a passing tropical wave. Expect similar conditions during the next day or so until the wave moves farther west. ATLANTIC OCEAN... A broad 1027 mb high centered over the Azores near 39N27W ridges SW to another weaker 1020 mb high centered near 26N57W then to the southeastern Gulf of Mexico. Moderate to locally fresh trade winds prevail south of the ridge to the west of 30W. For additional information please visit http://www.hurricanes.gov/marine $$ McElroy/ERA