000 AXNT20 KNHC 191758 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1258 PM EST Tue Nov 19 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 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...SPECIAL FEATURES... As of 1500 UTC, Tropical Storm Sebastein has formed and it is expected to remain over open waters. Sebastein is located near 20.1N 58.7W or about 275 nm NE of the Leeward Islands, moving toward the NNW at about 7 kt. Estimated central pressure is 1008 mb. The maximum sustained winds are near 40 kt with gusts up to 50 kt. Scattered moderate isolated strong convection is noted 250 nm SE of the center and scattered moderate convection 200 nm NE of the low. ASCAT show gale force winds in the NE quad from 18N-21N between 55W-59W. A turn to the north is expected on Wednesday followed by a turn to the northeast and an increase in forward speed Wednesday night. Some slight strengthening is possible over the next day or so. Sebastien is expected to become absorbed by a cold front in a couple of days. See latest NHC Forecast/Advisory under AWIPS/WMO header MIATCMAT5/WTNT35 KNHC for more details. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 38W from 12N southward, moving W at 5-10 kt. Scattered moderate to isolated strong convection is from 00N-06N between 34W-44W. A Caribbean Sea tropical wave is along 70W from 19N southward, moving W at 5-10 kt. Isolated showers are along the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of southern Sierra Leone near 07N12W to 05N15W. The ITCZ extends from 05N15W to 02N23W to 02N33W. Scattered moderate to strong convection is from 02S-09N between 13W-33W. GULF OF MEXICO... Two 1015 mb surface high is over the southwestern Gulf, near 23N92W. Weak surface ridging covers most of the Gulf, along with relatively dry air. Scatterometer show the light to moderate winds across the basin with no significant convection noted at this time. Weak high pressure over the western Gulf will shift NE through Wed. Fresh to strong SE return flow will develop over the NW Gulf Wed through Thu. A cold front will move off the Texas coast late Fri, followed by fresh to strong northerly winds Fri night into Sat. The front will rapidly move across the basin, and begin to weaken as it reaches the far SE Gulf Sat night. CARIBBEAN SEA... A stationary front passes through the Atlantic Ocean, from 31N65W to the Windward Passage near 19N74W. A surface trough continues to the eastern coast of Jamaica to 18N76W to 14N80W. Scattered moderate convection remains to the north of the Windward Passage while scattered showers extend 60 nm on either side of the trough. Broken multilayered clouds and scattered showers are to the west and northwest of the surface trough. ASCAT shows light east winds across the central Caribbean and light to moderate northerly wind in the NW Caribbean Sea. Tropical Storm Sebastien will move to 21.0N 59.2W this evening, 22.2N 60.0W Wed morning, then continue moving northward away from the area. Elsewhere, a weak trough extending from the Windward Passage across eastern Jamaica and into the SW Caribbean will dissipate tonight. A tropical wave will weaken late tonight into Wed as it moves across the central Caribbean. Fresh to strong NE winds will prevail through the Windward Passage Wed night through Fri. ATLANTIC OCEAN... See the Special Features section above for information on Tropical Storm Sebastein. A surface trough extends from 28N67W to near 22N73W in the SE Bahamas. Scattered showers and isolated thunderstorms are noted along the trough axis. Further E, a stationary front passes through the Atlantic Ocean, from 31N65W to the Windward Passage near 19N74W. Scattered moderate isolated strong convection is along the front from the Windward Passage near 19N73W to 24N68W. Surface high pressure ridging covers the Atlantic elsewhere east of 55W, anchored by a 1030 mb high near 32N38W. ASCAT support moderate to fresh east to southeast wind cover the Atlantic from 12N-28N between 18W-62W. The stationary front is expected to dissipate later today or tonight. Another forming cold front will quickly move across the northern waters tonight through Wed night, with fresh to strong W to NW winds developing behind the front. Sebastien will become merged into the frontal system by Thu night. High pressure will build across the northern waters Thu through Sat. Yet another cold front may move off the NE Florida coast late Sat night. Seas west of the W Atlantic stationary front, N and NE of the Bahamas, will continue to gradually subside through early this evening. A trough behind the stationary front will generate into a cold front and sweep across the rest of the western and central forecast waters this afternoon through Wed night. Fresh to strong west to northwest winds and building seas will follow in behind this front. High pressure will build across the northern waters Thu through Sat. Yet another cold front may move off the northeast Florida coast late Sat night. Fresh to strong southwest winds are forecast to develop over the far northwest waters beginning on Sat afternoon. $$ NATIONAL HURRICANE CENTER