000 AXNT20 KNHC 230610 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 110 AM EST Sat Nov 23 2019 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 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...SPECIAL FEATURES... Tropical Storm Sebastien is centered near 27.0N 52.2W at 23/0300 UTC or 920 nm NE of the Northern Leeward Islands moving ENE at 13 kt. Estimated minimum central pressure is 998 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Numerous moderate with isolated strong convection is from 25N to 30N between 49W and 55W. Gradual weakening is anticipated, and Sebastien is forecast to dissipate by early next week. The Public Advisories for Sebastien are available via AWIPS/WMO headers MIATCPAT5/WTNT35 KNHC. The Forecast/Advisories for Sebastien are available via the AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC. ...TROPICAL WAVES... A tropical wave is in the central Atlc from 00N to 10N with axis near 38W, moving W at 10-15 kt. Scattered moderate isolated strong convection is from 05N to 10N between 36W and 40W. A tropical wave is to the SE of the Windward Islands from 04N to 15N with axis near 56W, moving W around 10 kt. Scattered showers are S of 09N to the Guyana coast. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of Sierra Leone near 06N11W to 06N12W. The ITCZ continues from 06N12W to 04N26W to 03N37W, then continues W of a tropical wave from 03N40W to 01N50W. Scattered moderate to strong convection is seen north of the ITCZ from 05N-09N between 24W-36W and along the ITCZ from 15W-30W. For information on convection, see the Tropical Waves section. GULF OF MEXICO... Cold front has moved off the Texas coast into the NW Gulf extending from 29N93W to a 1012 mb low pressure in South Texas. A mix of low and mid level clouds and patchy fog are present ahead of the front. Scattered showers and isolated tstorms are developing ahead of the front from 24N-29N and west of 93W. Except for isolated showers and patchy fog along the NW Gulf coast, the remainder basin is under fair weather conditions being supported by a deep-layered anticyclone centered near the Yucatan Peninsula in the middle to upper levels. At the surface, the ridge is anchored by a 1020 mb high over the SW N Atlc and provides gentle to fresh return flow to the gulf as seen in the latest ASCAT pass. A surface ridge will prevail across the eastern area through tonight, with fresh SE return flow persisting over the western Gulf. The front will cross the northern and central waters this weekend, then weaken and stall over the southern Gulf Sun night into Mon. High pressure will build in from the W behind the front Sat night through Sun night, move E across the Gulf Mon into Tue, then persist into Wed night. The next cold front is expected to move into the northwest Gulf by Tue night into Wed night. CARIBBEAN SEA... A surface trough, remnants of a former tropical wave, is over the NW Caribbean waters extending from 18N85W to Nicaragua adjacent waters. Isolated showers are in the vicinity of this trough. The remnants of a former cold front are analyzed as a shearline extending from Guadeloupe SW to 15N61W to 14N72W. Scattered to isolated tstorms are within 60 nm either side of the shearline. This line of showers and tstms will gradually move SSE through Sat and then dissipate. Otherwise, the pressure gradient between T.S. Sebastien in the central Atlc and high pressure building over the SW N Atlc waters is supporting a swath of fresh winds N of 14N between the Mona Passage and the Dominican Republic. These winds will diminish Sat as Sebastian is expected to continue a NE track, which will weaken the pressure gradient. Easterly trades will freshen across the south-central Caribbean early next week, increasing to strong Tue into Tue night. ATLANTIC OCEAN... Please, see the Special Features section above for details on T.S. Sebastien. A 1020 mb high pressure is in the SW N Atlantic near 29N76W extending to 29N61W. To the east a cold front is present just west of the T.S. Sebastein extending from 31N47W to 28N52W then transitions to a stationary front to 22N55W, then extends as a front to 16N60W. Scattered showers and isolated tstorms are seen along the boundary. A surface trough is 110 nm ahead of the front from 16N57W to 23N52W with scattered moderate convection extending 180 nm E of the trough axis. Further E, a 1024 mb high pressure is in control over the NE Atlantic. High pressure in the wake of the front will dominate the forecast waters through Sat, then shift eastward Sat night. The next cold front will cross the region Sun through Mon, weakening near 70W Mon night through Tue night. High pressure will build in from the W over the region by mid week. Otherwise, surface ridging dominatesthe northeastern Atlc waters. $$ MMT