000 AXNT20 KNHC 212328 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 705 PM 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 1800 UTC surface analysis and satellite imagery through 2310 UTC. ...SPECIAL FEATURES... The center of Tropical Storm SEBASTIEN, at 21/2100 UTC, is near 23.8N 59.7W, or about 385 nm/715 km to the NNE of the northern Leeward Islands. Sebastien is moving NE, or 050 degrees, 8 knots. The estimated minimum central pressure is 998 mb. The maximum sustained wind speeds are 50 knots with gusts to 60 knots. Precipitation: scattered to numerous strong within 250 nm of the center in the NE quadrant. A cold front passes through 32N55W to 27N60W to 20N66W. The cold front is about 100 nm to the west of T.S. SEBASTIEN. Precipitation: isolated moderate to locally strong elsewhere within 300 nm to the east of the cold front from 20N northward. The PUBLIC ADVISORIES for SEBASTIEN are available via the WMO header WTNT35 KNHC, and via the AWIPS header MIATCPAT5. The FORECAST/ADVISORIES for SEBASTIEN are available via the WMO header WTNT25 KNHC, and via the AWIPS header MIATCMAT5. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 51W, from 13N southward, moving W 10 to 15 knots. Precipitation: isolated moderate to locally strong within 120 nm to the east of the tropical wave from 10N to 13N, and within 300 nm to the west of the tropical wave from 10N southward. A Caribbean Sea tropical wave is along 79W, from 15N southward, moving W 10 knots. Precipitation: isolated moderate from 14N to 17N between 76W and 81W. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of Sierra Leone near 09N13W, to 07N15. The ITCZ continues from 07N15W to 06N23W 02N32W 06N44W and 07N50W. Precipitation: isolated moderate to locally strong within 270 nm to the north of the ITCZ between 25W and 35W. Isolated moderate is from the ITCZ southward, between 29W and 36W. GULF OF MEXICO... An upper level ridge is along 89W/90W. Upper level anticyclonic wind flow spans the Gulf of Mexico. Broad surface anticyclonic wind flow covers the area. A surface ridge passes through the Florida Big Bend, into the east central Gulf of Mexico, to the Yucatan Peninsula of Mexico. A surface ridge will prevail across the area through Friday. Fresh SE return flow will persist in the western Gulf of Mexico. A cold front will move off the Texas coast and into the NW Gulf of Mexico on Friday night. The cold front will cross the northern and central waters this weekend. The cold front will weaken and stall in the southern Gulf of Mexico on Sunday night. CARIBBEAN SEA... A cold front passes through 20N66W in the Atlantic Ocean, across the easternmost part of the Dominican Republic, across the SW corner of the Dominican Republic, to the southern coastal waters of Jamaica, to 19N84W in the NW corner of the Caribbean Sea. Precipitation: isolated moderate within 300 nm to the E of the cold front, in the Atlantic Ocean from 17N northward toward T.S. SEBASTIEN. Isolated moderate within 150 nm to the north of Puerto Rico. Rainshowers are possible elsewhere, from the cold front northward, in the Caribbean Sea. A surface trough curves from central Honduras to Belize. Broken multilayered clouds and possible rainshowers are to the southwest of the line that runs from the NE point of the Yucatan Peninsula to the easternmost point of Honduras. Isolated moderate rainshowers are in the coastal waters of Nicaragua, to the west of the approaching 79W tropical wave. The current cold front, from 20N66W to 19N84W, will continue to move across the northern Caribbean Sea through tonight. The cold front will stall and weaken on Friday. Fresh NE winds will prevail across much of the western Caribbean Sea through Friday. The fastest wind speeds are expected through the Windward Passage and Mona Passage, as high pressure builds behind the cold front. Easterly trade winds will become fresh across the south central Caribbean Sea early next week. ATLANTIC OCEAN... A cold front passes through 32N63W, to 26N70W, through the central Bahamas, to NW Cuba. Precipitation: scattered moderate to strong within 90 nm to 180 nm to the east of the cold front, from 30N northward. One surface trough is along 30N62W 28N64W 26N65W. Precipitation: Isolated moderate to locally strong within 270 nm to the east of the surface trough from 25N to 30N. A second surface trough is along 25N67W 20N70W, reaching the north central coast of Hispaniola, and continuing to the southwestern corner of Haiti. Precipitation: isolated moderate within 75 nm on either side of the second surface trough. An upper level cyclonic center is near 21N41W. Upper level cyclonic wind flow covers the Atlantic Ocean from 11N to 29N between 34W and 50W. A surface trough is along 17N43W 13N44W 10N46W. Precipitation: isolated moderate to locally strong within 600 nm to the E and to the ESE of the surface trough. Isolated moderate elsewhere from 15N to 24N between 30W and 42W. A cold front passes through 32N14W, across the westernmost part of the Canary Islands, to 26N26W. Precipitation: rainshowers are possible within 180 nm to the SE and S of the cold front. Tropical Storm Sebastien near 23.8N 59.7W 998 mb at 4 PM EST moving NE at 8 kt. Maximum sustained winds 50 kt gusts 60 kt. Sebastien will strengthen to a hurricane while accelerating northeastward away from the forecast waters tonight. The current cold front, that is just to the west of the tropical storm, will continue moving eastward, and it will steer Sebastien into the central Atlantic Ocean. High pressure will build behind the cold front across the northern waters through Saturday, and then shift eastward on Saturday night. The next cold front will cross the region from Sunday through Monday. $$ mt