000 AXNT20 KNHC 042352 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 752 PM EDT Thu Oct 4 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 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...SPECIAL FEATURES... Tropical Storm Leslie centered near 33.3N 57.5W at 04/2100 UTC or 370 nm E of Bermuda moving N at 10 kt. Estimated minimum central pressure is 982 mb. Maximum sustained wind speed is 60 kt with gusts to 75 kt. Scattered moderate convection extends outward to 270 nm in the northwest quadrant and 210 nm in the other quadrants. A northward motion with an increase in forward speed is expected through tonight. A reduction in speed is forecast on Friday and Friday night, with Leslie turning toward the east-southeast over the weekend. Gradual weakening is forecast to continue during the next several days. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT3/WTNT33 KNHC for more details. ...TROPICAL WAVES... A far eastern Atlantic tropical wave extends its axis along 29W from 03N-15N, moving westward at 10-15 kt. Scattered moderate convection is noted within 270 nm of the wave axis from 04N-13N. GOES-16 Total Precipitable Water imagery shows a moisture maximum surrounding the wave. The wave has an associated 700 mb trough, as depicted by model analyses. A central Atlantic tropical wave is along 47W from 06N-15N moving westward around 10 kt. Scattered showers are occurring along the wave axis and extending to 180 nm east of the wave axis from 08N- 15N. The wave has an associated 700 mb trough, as shown by model analyses. An eastern Caribbean tropical wave has its axis along 68W from 09N-19N, moving westward around 10 kt. Scattered moderate convection is observed in the vicinity of this wave enhanced by upper level diffluence prevailing across the central Caribbean west of the wave. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Guinea-Bissau near 11N15W to 10N20W to 07N33W. The ITCZ extends from 07N33W to 08N45W, then continues west of a tropical wave from 08N48W to the coast of northeast Venezuela near 09N61W. Aside from the convection mentioned in the tropical waves section above, isolated showers and thunderstorms are noted along and within 120 nm north of the ITCZ between 51W-56W. Scattered moderate and isolated strong convection is occurring along the west coast of Africa over Guinea-Bissau and western Guinea. This scattered activity extends offshore the west coast of Africa for 120 nm from 06N-12N. ...DISCUSSION... GULF OF MEXICO... Scattered showers are moving westward over the northern Gulf from 25N-30N between 87W-92W. This activity is being enhanced by an area of upper-level diffluence over the Gulf stemming from an upper-level ridge over the south-central U.S. GOES-16 TPW imagery shows that the highest moisture in the area is near 90W-92W moving westward. These showers and storms should diminish before reaching 94W as they encounter increasingly pronounced low and mid level ridging. A surface trough is analyzed over the central Bay of Campeche. Scattered showers are noted west of the trough, just offshore the coast of Mexico between Veracruz and Tampico. Expect ridging to prevail over the forecast area through the weekend. A surface trough will develop each evening over the Yucatan Peninsula. The trough will move into the SW Gulf overnight, where it will dissipate each morning. Moderate to fresh winds will accompany the trough. CARIBBEAN SEA... A large cyclonic gyre, defined by a broad area of low pressure, covers a portion of Central America and the western Caribbean Sea. Within this gyre, a surface trough is analyzed from 20N80W to a 1007 mb low near 15N83W to 11N84W. Satellite imagery shows scattered moderate to isolated strong convection across the central Caribbean between 69W-80W. Some slow development of this system is possible this weekend or early next week as the system drifts northwestward across the northwestern Caribbean and the southern Gulf of Mexico. A mid to upper level trough extending over the Bahamas and Greater Antilles will help advect moisture northwestward over the next several days. As a result, heavy rainfall is likely to spread over portions of Hispaniola, Jamaica, Cuba, the Yucatan Peninsula and Central America Friday through early next week. A tropical wave is over the eastern Caribbean. Refer to the Tropical Waves section above for details. Large NNE swell generated from Leslie will continue to pass through the Atlantic passages into the Caribbean through the end of the week before subsiding. ATLANTIC OCEAN... Two tropical waves are over the tropical Atlantic between the west coast of Africa and the Lesser Antilles. See above for details. Leslie is described in the Special Features section above. A weak surface trough located near the east coast of South Florida is enhancing coverage of showers over the NW Bahamas and the southern and central Florida peninsula. This activity should continue through this evening as the trough moves westward. Another surface trough is analyzed from 21N61W to 23N57W with scattered showers. An E-W surface trough is analyzed to the east of Leslie from 31N47W to 30N33W. Scattered showers and thunderstorms are seen south of this trough from 25N-28N between 32W-40W. Enhanced moisture from the tropical wave along 47W is streaming northeastward between an upper-level trough to the northwest and an upper-level ridge to the southeast. A high pressure ridge off the southeast coast of the U.S. is leading to generally quiet weather in the area between Bermuda and the Bahamas. For additional information please visit http://www.hurricanes.gov/marine $$ ERA/AH