000 AXNT20 KNHC 300005 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM EDT THU SEP 29 2016 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 2345 UTC. ...SPECIAL FEATURES... Hurricane Matthew at 30/0000 UTC is centered near 14.2N 68.1W or about 130 NM...240 KM east-northeast of Curacao, moving west at 13 KT. Maximum sustained winds are 65 KT with gusts to 80 KT. Estimated minimum central pressure has fallen to 987 mb. Scattered to numerous strong convection are observed within 90 NM in the S and 60 NM in the N semicircles...with a band of strong convection within 60 Nm of a line from 13N65W to 10N66W. Matthew is expected to slowly strengthen over the new few days as it moves west-southwest over the central Caribbean. Please refer to the NHC forecast/advisory under AWIPS/WMO headers WTNT24 KNHC/TCMAT4, or visit the NHC website at http://hurricanes.gov for additional details. ...TROPICAL WAVES... A tropical wave is in the E Atlantic extending along 26W/27W from 09N to 20N, moving west at 15 kt over the past 24 hours according to satellite imagery. TPW imagery depicted abundant moisture associated with the wave. However convection was limited to near the intersection of the wave axis and and the monsoon trough. The tropical wave noted earlier in the Central Atlantic along 34W/35W has been removed from the analysis. Satellite hovmoller and easterly wave diagnostics suggest the vorticity associated with the feature was derived from the tropical wave analyzed along 47W/48W. No significant convection was noted. A tropical wave is in the Central Atlantic with axis from 15N45W to 05N49W, moving west at 15 to 20 kt over the past 24 hours. The wave was situated in an area of strongly diffluent upper level which resulted in scattered moderate isolated strong convection from 08N to 11N between 47W and 50W. The weak tropical wave in the west Caribbean along 89W earlier has moved inland over the Yucatan peninsula and has become diffuse. However, scattered moderate to strong convection was noted over the Yucatan, Guatemala and Honduras. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends over Africa reaching the east Atlantic near 16N16W through 10N33W to 09N45W. The ITCZ begins near 08N33W to 07N59W. Aside from the convection associated with the tropical waves, scattered moderate convection was noted from 06N to 09N between 20W and 23W. and within 90-120 NM of the coast of Senegal. ...DISCUSSION... GULF OF MEXICO... A broad deep layered cyclonic circulation centered over Kentucky and associated trough with mean axis along 85W dominated the eastern half of the Gulf of Mexico and provided support for a cold front extending from the Big Bend of Florida through 27.5N90W to 25N95W. Strong upper level subsidence was occurring in the wake of the upper trough and was pressing southward as the trough continued to amplify. A large anticyclone over Mexico near 23N104W dominated the flow over the southwestern third of the Gulf with moderate to strong northwesterly flow aloft spreading mid level moisture across the Bay of Campeche and the Yucatan peninsula. Diffluent flow aloft was providing support for scattered showers and isolated thunderstorms from Florida to to the Yucatan channel...and weaker shower activity within 60-90 NM wither side of a surface trough extending from 25N96W to 20N95W. The cold front will continue moving south across the eastern Gulf during the next 24 hours. Convection will prevail ahead of this boundary affecting the southern Gulf waters. CARIBBEAN SEA... The main feature of concern in the Caribbean is Hurricane Matthew located south of Puerto Rico. Matthew remains embedded within an area of diffluent anticyclonic flow aloft as it treks westward. Please refer to the special features section above for details. An upper- level trough extends across the Florida Peninsula reaching the west Caribbean waters west of 80W. Scattered showers are observed south of 16N between 80W-84W affecting portions of Nicaragua and Honduras as well as their adjacent waters. Isolated showers are observed south of 10N between 78W-82W due to the proximity of the EPAC Monsoon Trough. Scatterometer data depicts moderate to fresh northeasterly winds across the basin west of 70W. Expect for Matthew to become a hurricane within the next 24 hours. This system will continue moving west through Friday. ...HISPANIOLA... High cloudiness is spreading across the eastern Dominican Republic in advance of Hurricane Matthew. The forecast track of the hurricane should keep the bulk of the heavy precipitation to the south of Hispaniola. However an increase in the overall moisture could lead to localized heavy rain in orographically favored areas. As Matthew turns northward late SUN or MON, the potential exists for additional heavy rains over Haiti. For additional information on Matthew, please refer to the special features section above. ATLANTIC OCEAN... Two tropical waves are moving across the basin. Please refer to the section above for details. A broad mid-level trough extends across the southeast CONUS and covers the west Atlantic waters W of 70W, supporting scattered showers and thunderstorms between 70W-80W. The remainder of the basin is dominated by a surface ridge anchored by a 1036 mb high in the north central Atlantic near 42N37W. For additional information please visit http://www.hurricanes.gov/marine $$ COBB