000 AXNT20 KNHC 241744 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 144 PM EDT WED AUG 24 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... Tropical Storm Gaston is centered near 16.1N 39.4W at 24/1500 UTC or about 886 nm west of the Cabo Verde Islands moving northwest at 14 kt. Estimated minimum central pressure is 999 mb. Maximum sustained wind speed is 60 kt with gusts to 75 kt. Scattered moderate convection is from 14N-19N between 36W-44W. Please see the latest NHC Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT2/WTNT32 KNHC and the full Forecast/Advisory under the AWIPS/WMO headers MIATCPAT2/WTNT22 KNHC for more details. A tropical wave moving across the Lesser Antilles with axis extending from 21N66W to a 1009 mb low near 18N63W to 12N61W. At this time, scattered moderate convection is observed from 15N-21N between 61W-68W. As of 25/1500 UTC; an Air Force Reconnaissance aircraft and latest scatterometer data reported gale force winds from 17N-20N between 61W-65W in association to this system. Although environmental conditions are currently marginally conducive for additional development, this system could become a tropical depression or tropical storm at any time during the next few days while it moves west-northwestward at about 10-15 kt across the northern Leeward Islands, Puerto Rico, Hispaniola, and the Bahamas. Strong winds, heavy rains, and flash floods and mudslides are possible across these islands. This system has a medium chance of tropical formation through the next 48 hours. ...TROPICAL WAVES... See above. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 18N16W and continues to 08N27W. The ITCZ begins near 09N43W and continues to 06N57W. Clusters of moderate convection are south of the Monsoon Trough mainly south of 10N east of 20W. ...DISCUSSION... GULF OF MEXICO... A surface ridge prevails across the basin anchored by a 1020 mb high centered near 28N93W. To the east of this feature; a surface trough extends from 30N86W to 26N88W with isolated moderate convection. Another surface trough extends over the southeast Gulf waters and the southern portion of the Florida Peninsula from 25N83W to 26N80W. Scattered moderate convection is observed along this boundary. Scatterometer data and surface observations depict a gentle to moderate anticyclonic flow across the basin. Expect during the next 24 hours for the surface ridge to shift northward. Convection will continue across the southeast waters. CARIBBEAN SEA... The primary concern this morning is the tropical wave/low moving through the Lesser Antilles. Please see the Special Features section above for more information. An elongated upper-level low is centered in the western Caribbean near 18N85W. This feature is supporting isolated moderate convection mainly west of 78W. To the south; the Monsoon Trough extends north of Panama along 10N supporting scattered moderate convection between 76W-83W. Scatterometer data depicts moderate to fresh trades across most of the area except south of 13N between 73W-78W where fresh to strong winds prevail. As of 25/1500 UTC; an Air Force Reconnaissance aircraft and latest scatterometer data reported gale force winds north of 17N and east of 64W in association to the tropical wave/low pressure in the eastern Caribbean. Expect through the next 24 hours for the surface low to continue moving west-northwest with convection and gusty winds. Little change is expected elsewhere. ...HISPANIOLA... Showers and thunderstorms associated with the tropical wave and low in the Lesser Antilles are approaching the island at this time. Expect weather conditions to deteriorate as these features continue moving west. The low is expected to be north of the Mona Passage late tonight then northwest of Haiti by late Thursday night. Gusty winds, heavy rains, and flash floods and mud slides are possible across the island. ATLANTIC OCEAN... The areas of concern across the basin are the east-central Atlantic due to Tropical Storm Gaston and the possible development of the low and tropical wave currently moving across the Lesser Antilles. Please see the Special Features section above for details. A surface trough extends across the western Atlantic from 26N80W to 29N75W. Scattered moderate convection prevails along the trough and over the adjacent area from 26N-28N. A stationary front extends from the end of the surface trough to 32N67W. Isolated convection is observed along the front. To the east; a 1016 mb surface low is centered near 28N67W. Scattered moderate convection is from 28N-31N between 60W-68W. Another surface trough extends across the central Atlantic from 26N51W to 31N47W. Scattered moderate convection prevails within 100 nm on either side of this boundary. Surface ridging dominates the remainder of the basin. Expect for the Special Features low/tropical wave to track northwest through the Bahama chain before reaching the northwest Bahamas this weekend. Tropical Storm Gaston is will remain east of 60W as it tracks northwest before turning northward by Sunday. For additional information please visit http://www.hurricanes.gov/marine $$ ERA