442 AXNT20 KNHC 032354 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 754 PM EDT Wed Oct 3 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... Hurricane Leslie centered near 29.9N 56.9W at 03/2100 UTC or 430 nm ESE of Bermuda moving N at 3 kt. Estimated minimum central pressure is 975 mb. Maximum sustained wind speed is 70 kt with gusts to 85 kt. Scattered to numerous moderate convection is noted within 120 nm of the center. Little motion is expected for the next several hours. A northward motion is forecast to begin this evening, and this motion with an increase in forward speed should continue through Friday night. A turn to the east is expected this weekend. Some additional strengthening is forecast during the next day or so, but a slow weakening trend is expected to begin on Friday. 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 23W from 03N-15N, moving westward around 10-15 kt. Scattered moderate convection is within 90 nm on either side of the wave's axis. Total Precipitable Water imagery shows deep moisture surrounding the wave. The wave has an associated 700 mb trough, as shown by model analyses. A central Atlantic tropical wave is along 41W from 05N-14N moving westward around 10-15 kt. Scattered showers and thunderstorms are occurring along and west of the wave's axis between 41-48W. The wave has an associated 700 mb trough, as shown by model analyses. An eastern Caribbean tropical wave has its axis along 64W from 06N-18N, moving westward at 10-15 kt. A TPW animation shows a slight moisture maximum associated with the wave. The wave is not producing any significant convection due to an area of mid-level ridging and sinking air that prevails across the eastern Caribbean. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of west Africa near the Senegal/Mauritania border near 16N16W to 09N20W to 07N25W to 09N40W. The ITCZ extends from 09N41W to 08N59W. Aside from the convection mentioned in the tropical waves section above, isolated showers are observed within 240 nm north of the ITCZ between 48W-53W. ...DISCUSSION... GULF OF MEXICO... A surface trough is moving slowly westward over the northern Gulf, and is analyzed along 87W between 26N-28N. Scattered showers are occurring within 60 nm of the trough axis. Enhanced moisture associated with this trough is seen on GOES-16 TPW imagery. Enhanced convection will continue through today offshore the northern Gulf coast in association with this trough. Scattered showers are over the Bay of Campeche south of 21N and west of 94W. Surface ridging prevails across the northwest Gulf. Little to no shower activity is observed north of 24N and west of 90W. Expect ridging to prevail over the forecast area during the next few days. 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 tropical wave is over the eastern Caribbean. Refer to the Tropical Waves section above for details. A broad surface trough is over the western Caribbean, analyzed from 18N78W to a 1007 mb low near 16N80W to 12N83W. This position is supported by a recent ASCAT pass. Satellite imagery shows scattered moderate convection prevailing across the western Caribbean mainly west of 75W. Some slow development of this system is possible this weekend while the low drifts across the northwestern Caribbean Sea. A mid to upper level trough extending over the Bahamas and Greater Antilles will help advect moisture northward as the week progresses. As a result, very heavy rainfall is likely to spread over sections of Hispaniola and Jamaica later this week and into the weekend. Another area of convection that was generated yesterday closer to the aforementioned trough axis has been drifting eastward and is gradually weakening as it moves farther from the trough. This area of scattered moderate convection is located from 13N-15N between 69W-72W. Upper-level diffluence in this area is becoming less pronounced, so expect the convection in this area to become less intense over the next 12 hours. Large NNE swells generated from Leslie will continue to move through the Atlantic passages into the Caribbean during the next few days. ATLANTIC OCEAN... Two tropical waves over the tropical Atlantic between the west coast of Africa and the Lesser Antilles are described in the Tropical Waves section above. Hurricane Leslie is described in the Special Features section above. An area of upper-level diffluence just east of the central Bahamas is causing scattered showers and thunderstorms from 25N-27N between 71W-75W. This activity could continue in this area over toward the central Bahamas through this evening. An E-W surface trough is analyzed to the east of Hurricane Leslie along 31N between 36W-42W. Scattered moderate convection is seen along and south of this trough to 29N. Another surface trough is analyzed south of Hurricane Leslie from 25N56W to 20N67W. Scattered showers are occurring along this trough. GOES-16 Total Tropical moisture from the vicinity of 17N61W is being transported northeastward to the vicinity of the surface trough near 30N36W. The moisture is following the mid to upper level flow in between the cyclonic flow associated with Leslie and anticyclonic flow in the vicinity of 23N43W. Surface ridging generally prevails over the eastern Atlantic, leading to quiet weather from 19N-27N east of 40W. For additional information please visit http://www.hurricanes.gov/marine $$ AG/ERA