691 AXNT20 KNHC 291722 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 122 PM EDT Sat Sep 29 2018 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 1715 UTC. ...SPECIAL FEATURES... Sub-tropical Storm Leslie centered near 34.4N 50.8W at 29/1500 UTC or 710 nm ENE of Bermuda moving SW at 6 kt. Estimated minimum central pressure is 991 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Some strengthening is forecast during this time period also. Scattered moderate convection is from 31N-36N between 47W-52W. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT3/WTNT33 KNHC for more details. ...TROPICAL WAVES... A tropical wave has its axis along 27W from 02N-18N, moving W at 10-15 kt. Scattered showers are noted south of 10N, where the wave meets the monsoon trough. This feature shows up well in the Total Precipitable Water animation, and continues to have a sharp trough at the surface as seen on the latest scatterometer pass. A tropical wave has its axis along 49W from 07N-19N, moving W at 10 kt. The TPW imagery shows a maximum E of the wave's axis and there is a trough in the GFS 700 mb analyses, but little signature is seen at the surface. Scattered showers are developing within 75 nm to the east of the wave's axis between 10N-13N. A tropical wave extends across the eastern Caribbean, with axis along 68W and between 07N-19N. TPW imagery depicts abundant moisture in the eastern Caribbean mainly east of 70W. Scattered moderate convection is observed east of the wave's axis from 11N- 17N between 61W-67W. A tropical wave is moving across the west Caribbean along 87W from 21N southward. A pronounced 700 mb trough in the GFS analysis is noted with the wave, but little signature of the wave is seen at the surface. The wave, along with the monsoon trough, is enhancing scattered showers within 180 nm of the wave's axis mainly south of 15N. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the eastern Atlantic near 13N17W and continues SW to near 07N26W. The ITCZ extends from 06N30W to 08N47W, then resumes W of a tropical wave near 09N51W and extends to the coast of South America near 09N60W. Scattered moderate convection is noted along the monsoon trough and over the ITCZ between 30W-35W. ...DISCUSSION... GULF OF MEXICO... The tail end of a stationary front extends from S Mississippi to SW Louisiana. Scattered showers are within 120 nm of the front affecting the northwest Gulf waters north of 27N and west of 90W. A surface trough extends across the Bay of Campeche along 97W with scattered moderate convection. Current winds across the basin are gentle to moderate. Little change is expected over the gulf waters during the next couple of days. Seas will remain below 8 ft through the weekend. CARIBBEAN SEA... Two tropical waves are moving across the basin. See the Tropical Waves section above for details. Recent scatterometer data indicate that gentle to moderate trades prevail across most of the basin except in the vicinity of the tropical wave across the eastern Caribbean. In this area, fresh winds prevail mainly east of 66W. Large northerly swell associated with Leslie will affect the tropical Atlantic waters tonight through Sunday, building seas to 10-11 ft. ATLANTIC OCEAN... Two tropical waves are currently between the coast of Africa and the Lesser Antilles. See the Tropical Waves section above for details. A surface trough enters the forecast region near 30N39W then continues SW to 21N48W with scattered to numerous showers and thunderstorms. This feature is associated with Leslie, currently centered N of the area. Please, see the Special Features Section above for more details. Large swell generated by Leslie is expected to propagate across the waters east of 75W, reaching the Bahamas the waters N of Hispaniola and the Atlantic Passages E of la Mona Passage today, and the north and central coast of Florida by tonight. A ridge extends from a 1021 mb high pressure located near 31N70W across the western Atlantic reaching Florida. Another ridge dominates the remainder of the Atlantic E of the aforementioned trough. For additional information please visit http://www.hurricanes.gov/marine $$ ERA