000 AXNT20 KNHC 281743 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 143 PM EDT WED SEP 28 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 1200 UTC surface analysis and satellite imagery through 1730 UTC. ...SPECIAL FEATURES... The tropical wave and surface low described in this section in the previous discussion has developed into Tropical Storm Matthew as of 28/1500 UTC, centered near 13.4N 60.7W, or about 31 nm southeast of St. Lucia and St. Vincent. The minimum central pressure of Matthew is 1008 mb and is moving west at 18 kt. Maximum winds are 50 kt with gusts to 60 kt. Scattered moderate to strong convection is observed from 11N-17N between 55W-64W affecting the Lesser Antilles and eastern Caribbean waters. 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... An Atlantic Ocean tropical wave extends its axis from 18N28W to 05N28W, moving westward at 10 to 15 kt. Abundant moisture prevails east of the wave's axis as noted in TPW imagery. The precipitation observed in the vicinity of this wave is related to the Monsoon Trough and prevails east of 27W. A tropical wave extends across the western Caribbean with axis from 17N79W to 08N79W, moving westward at 15 kt. The wave is moving into the area of an upper-level low currently centered near 16N82W. Scattered moderate convection is observed in the area where the wave interacts with the Monsoon Trough mainly south of 11N between 76W-81W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends over Africa reaching the east Atlantic near 10N15W to 09N28W to 07N34W to 08N44W. Scattered moderate convection is observed from 05N-11N between 14W-26W. Isolated showers prevail along the remainder of the boundary. ...DISCUSSION... GULF OF MEXICO... An upper-level anticyclonic circulation is centered over eastern Mexico near 23N99W. Upper-level anticyclonic wind flow prevails across most the basin. An upper-level trough extends east of 83W across the far east Gulf waters and Florida Peninsula. At the surface; a trough extends over the Bay of Campeche from 27N95W to 20N95W. Scattered moderate convection prevails along this boundary affecting the waters west of 93W. To the northeast; a cold front extends from 28N91W to 30N86W. Scattered showers are observed north of 26N and east 89W. Gentle to moderate southeasterly winds prevail across the basin. Expect during the next 24 hours for the cold front to continue moving east with showers. The surface trough over the Bay of Campeche will continue enhancing convection. CARIBBEAN SEA... A tropical wave is moving across the western Caribbean while T.S Matthew is will enter the eastern Caribbean within the next few hours. Please refer to the section above for details. An upper- level low is centered near 16N82W enhancing convection from 11N- 14N and west of 82W affecting portions of Nicaragua. The Monsoon Trough extends along 10N between 75W-80W with scattered moderate convection. An upper-level trough extends from 68W-75W supporting isolated convection just north of 14N. Scattered moderate convection is entering the far east Caribbean waters due to Matthew. Scatterometer data depicts moderate to fresh trades across the basin. Expect during the next 24 hours for the tropical wave and Matthew to move west across the basin. ...HISPANIOLA... An upper-level trough extends from 68W-75W across the island supporting isolated convection just north of 17N between 69W-71W. Expect for this trough to weaken within the next 24 hours. Isolated showers are still expected. ATLANTIC OCEAN... T.S. Matthew has developed in the central Atlantic while a tropical wave extends along 28W. Please refer to the sections above for details. A surface trough extends across the west Atlantic from 25N79W to 32N76W. Scattered moderate convection is north of 26N between 75W-79W. To the east; a weakening stationary front extends over the central Atlantic from 29N52W to 31N44W. No significant convection is observed with this feature at this time. The remainder of the basin is under the influence of a surface ridge anchored by a 1030 mb high centered near 38N48W and a 1032 mb high near 39N43W. For additional information please visit http://www.hurricanes.gov/marine $$ ERA