000 AXNT20 KNHC 210524 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1224 AM EST Thu Nov 21 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 0510 UTC. ...SPECIAL FEATURES... Tropical Storm Sebastien is centered near 22.2N 61.5W at 21/0300 UTC, or about 255 nm NNE of the northern Leeward Islands, moving N at 6 kt. Estimated minimum central pressure is 999 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Numerous moderate with scattered strong convection is within 180 nm of the center in the E semicircle. Scattered moderate convection is elsewhere within 270 nm E semicircle and 180 nm NW quad. A turn to the NE is expected today, followed by an increase in forward speed. Sebastien could strengthen to a hurricane by this evening when it moves to near 25.5N 58W. Sebastien is forecast to become extratropical Friday evening when it reaches near 31N49W. Public Advisories for Sebastien are available via AWIPS/WMO headers MIATCPAT5/WTNT35 KNHC. Forecast/Advisories for Sebastien are available via AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 47W from 13N southward, moving W around 15 kt. Isolated moderate convection is seen from 05N-09N between 42W-49W. A Caribbean Sea tropical wave is along 74/75W from 19N southward, moving W at 5-10 kt. Isolated showers are from 12N-15N between 75W-77W. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coast of Liberia near 07N11W to 04N16W. The ITCZ continues from 04N16W to 01N25W to 03N33W to 04N42W. Isolated moderate convection is from 00N-09N between 22W-40W, and from 04N-07N between 10W-12W. GULF OF MEXICO... Mid to upper-level anticyclonic wind flow spans the Gulf of Mexico, with little to no precipitation seen across the basin. Fresh southeasterly return flow is occurring over the western Gulf of Mexico. Surface ridging will prevail across the region. Fresh SE return flow will continue over the NW Gulf through today ahead of a cold front moving over Texas. The front will move into the NW Gulf by late Fri, cross the region through the weekend, and weaken and stall over the southern Gulf by late Sunday. CARIBBEAN SEA... A cold front passes through the central Bahamas to Cuba near 22N79W to 21N84W. A surface trough over the Gulf of Honduras is leading to possible isolated showers from 15N-20N between 84W-88W. Another surface trough extends over the Atlantic from 25N67W southwestward to Hispaniola near 18N73W. Scattered showers and tstorms are seen near and over Hispaniola from 17N-20N between 68W-73W. Elsewhere, subsidence and dry air are present. The latest ASCAT pass shows fresh to locally strong N to NE winds in the Windward Passage, and in the Caribbean between Jamaica and eastern Cuba. Fresh NE winds will prevail across most of the western Caribbean through Fri morning, with the strongest winds expected through the Windward and Mona passages tonight as high pressure builds north of the region. ATLANTIC OCEAN... For information on T.S. Sebastien, see Special Features section above. A cold front passes through 32N62W to 27N67W to 23.5N74W to 21N84W. The latest ASCAT pass shows strong NW winds north of 29N between 64W-72W. A surface trough extends from 26N67W to Hispaniola near 18N73W. Isolated to scattered showers and tstorms are along the trough from Hispaniola to 24N67W. Another surface trough extends from 28N62W to 24.5N64W. Fresh S winds are east of the surface trough. Scattered moderate to strong convection is along the trough and ahead of the cold front, from 25N-32N between 57W-64W. An upper level cyclonic center is near 19N41W. Scattered moderate convection is SE of the upper-low from 14N-20N between 30W-40W. Farther E, a cold front extends from the coast of Morocco near 31N10W to 27N20W to 26N31W. Gentle winds are on both sides of the front. Scattered moderate showers are north of 29N and east of 12W. Surface ridging prevails elsewhere, anchored by a 1025 mb high near 32N41W. The cold front that extends from 32N62W to the central Bahamas to west-central Cuba will continue to move southeastward across the region through today. High pressure will build across the northern waters today through Sat, then shift eastward Sat night through Sun as the next cold front moves off the SE U.S. coast. $$ Hagen