000 AXNT20 KNHC 211115 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 615 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 0600 UTC surface analysis and satellite imagery through 1100 UTC. ...SPECIAL FEATURES... Tropical Storm Sebastien is centered near 23.0N 61.2W at 21/0900 UTC, or about 310 nm NNE of the northern Leeward Islands, moving NNE at 7 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 240 nm of the center in the SE quadrant. Scattered moderate with isolated strong convection is elsewhere within 270 nm E semicircle and 240 nm NW quad. A faster NE motion is expected during the next few days. Sebastien could strengthen to a hurricane tonight or Friday before weakening this weekend. 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 48W from 13N southward, moving W at 15 kt. Isolated moderate convection is seen from 05N- 09N between 41W-53W. A Caribbean Sea tropical wave is along 76/77W from 18N southward, moving W at 10 kt. Isolated showers are near the wave axis from 12N-15N. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coast of Liberia near 07N11W to 05N14W. The ITCZ continues from 05N14W to 01N27W to 03N33W to 04N45W. Isolated moderate convection is from 00N-10N between 23W- 44W, and from 03N-06N between 04W-09W. 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 continue across the area through Fri, along with fresh SE return flow over the NW Gulf ahead of a cold front moving into Texas. The front will reach the NW Gulf Fri night, move across the northern and central waters through the weekend, then weaken and stall in the southern Gulf Sun night. CARIBBEAN SEA... A cold front passes through the Windward Passage to the Cayman Islands to 20N84W. Isolated showers are near the front. Scattered showers and tstorms are near and over Hispaniola, north of 16.5N between 68W-72W. A surface trough over the western Gulf of Honduras is leading to possible isolated showers there. 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. The cold front over the basin will weaken and stall tonight across the northern Caribbean from the Mona Passage to Jamaica. Fresh NE winds will prevail across most of the western Caribbean through Fri morning, with the strongest winds expected in the Windward and Mona passages as high pressure builds behind the cold front. ATLANTIC OCEAN... For information on T.S. Sebastien, see Special Features section above. A cold front passes through 32N59W to 25N65W to 21N70W to the Windward Passage to the Cayman Islands. A pre-frontal surface trough is from 30N59W to 26N60W. Numerous moderate with isolated strong convection is along and E of the cold front from 25N-32N between 56W-63.5W. The latest ASCAT pass shows strong NW winds north of 29N between 64W-72W. Fresh S winds are east of the surface trough. An upper level cyclonic center is near 19N42W. Scattered moderate convection is SE of the upper-low from 15N-22N between 29W-40W. In the northeast part of the area, a cold front extends from the coast of Morocco near 31N10W to 26N18W to 25N25W to 25N30W. Gentle winds are on both sides of the front. Scattered moderate convection is north of 31N east of 14W. Another cold front extends from 32N19W to 30N25W to 31N29W. Surface ridging prevails elsewhere, anchored by a 1024 mb high near 32N39W. The cold front extending from 25N65W to the Windward Passage will help steer Sebastien into the central Atlantic. High pressure behind the cold front will build across northern waters through Sat, then shift eastward Sat night and Sun as another cold front moves off the SE U.S. coast. $$ Hagen