Tropical Weather Discussion
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000 AXNT20 KNHC 191722 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 122 PM EDT Sat Oct 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 1700 UTC. ...SPECIAL FEATURES... Nestor has lost its tropical characteristics and is now a post- tropical cyclone as of 19/1500 UTC, centered near 29.3N 86.3W, or about 60 nm SSW of Panama City. Nestor is moving to the ENE at 8 kt. Estimated minimum central pressure is 996 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. No deep convection is seen within 270 nm of the center. However, scattered showers are over the northeastern Gulf of Mexico. The deeper convection (scattered moderate to isolated strong) is seen within the area bounded by 31N81W to 21N87W to 24N77W to 31N76W to 31N81W, which includes SE Florida, the NW Bahamas, Florida Straits and Yucatan Channel. On the forecast track, Nestor will move across portions of the southeastern United States later tonight and Sunday. Gale-force winds are expected to develop later this afternoon in relation to Nestor over the west Atlantic waters mainly north of 29.5N and west of 78W. These conditions will continue through early Sunday morning. Nestor is expected to move offshore of the coast of North Carolina into the western Atlantic by late Sunday. See the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMAT1/WTNT21 KNHC or the website hurricanes.gov for more details. For more information about the Gale Warning, refer to the High Seas Forecast product, under WMO/AWIPS headers FZNT02 KNHC/HSFAT2. ...TROPICAL WAVES... An eastern Atlantic tropical wave extends its axis along 23W from 14N southward, moving W at 10-15 kt. Isolated moderate showers are noted along the wave axis south of 11N. A central Atlantic tropical wave extends its axis from 14N37W to 08N39W to 01N40W, moving W around 10 kt. This position corresponds well with where the models indicate the 700 mb trough axis. ASCAT shows that a surface trough axis is along 36W or about 2 to 3 degrees east of the wave axis. Scattered to numerous moderate convection is more co-located with the surface trough, from 09N- 14N between 32W-38W. Scattered showers are seen from 08N-12N between 28W-32W and also along and within 90 nm E of the wave axis from 04N-09N. An eastern Caribbean tropical wave extends its axis along 69W from 20N southward, moving W at 10-15 kt. The most recent ASCAT pass continues to depict a surface trough with this wave. Scattered moderate showers are seen from 08N-18N between 62W-72W. A tropical wave extends across Central America with axis along 88W from 02N-17N, moving W around 5 kt. The northern part of the wave will soon be exiting the western Gulf of Honduras and exiting the basin. Isolated showers are over the Gulf of Honduras south of 19N and west of 84.5W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from 16N17W to 13N20W to 06N25W to 05N29W. The ITCZ extends from 05N29W to 06N33W, then continues W of a tropical wave from 05N42W to 05N53W. Aside from the convection related to the tropical waves described above, isolated showers are along and within 150 nm N of the ITCZ between 42W-46W. Scattered showers are also off Africa from 02N-08N, east of 17W. GULF OF MEXICO... Post-tropical cyclone Nestor is over the Gulf of Mexico. See the Special Features section above for details. As of 1500 UTC, a cold front extends SW from Nestor to 27N88W. A warm front extends from Nestor to Tallahassee Florida to 30N80W. A 1010 mb surface high pressure is located in the western Gulf of Mexico near 26N92W. A 1007 mb surface low is west of Brownsville Texas near 26N99W. Scattered moderate convection extends from near Key West and Cape Sable Florida westward to the Yucatan Channel from 21N-26N between 81.5W-87W. Nestor will move inland along the Florida panhandle around 1800 UTC today, then move farther away from the Gulf of Mexico as it moves NE over the southeastern U.S. and then into the western Atlantic. Winds in the NE Gulf will diminish to below 25 kt this evening and to below 15 kt Sunday morning. Wave heights in the NE Gulf will subside to below 10 ft by late this afternoon and to below 8 ft this evening. A cold front will reach the NW Gulf Mon night, and extend across the basin from northern Florida to NE Mexico on Tue night. CARIBBEAN SEA... An upper-level trough axis is over the central Caribbean near, or just west of, the tropical wave along 69W. The upper-trough is acting to enhance the convection described above in the tropical waves section. Upper-level ridging and relatively dry air cover much of the western portion of the Caribbean. The exception is in the Yucatan Channel, where scattered moderate convection is seen north of 21N and east of 87W. ASCAT shows fresh southerly winds in the Yucatan Channel, as well as in the NW Caribbean north of 17N between 83W-87W. Moderate trades prevail across the remainder of the Caribbean, except for locally fresh near the tropical wave along 69W. In the SW Caribbean, the East Pacific monsoon trough is inducing scattered moderate showers over NE Venezuela, N Colombia, eastern Panama, and the Caribbean waters south of a line from 13N71W to 10N80W. Moderate to fresh trade winds will prevail across most of the the basin through Wed night. Fresh SE winds are likely near the Yucatan Channel today as Tropical Storm Nestor moves NE across the Gulf of Mexico. The active tropical wave along 69W will move W and reach the western Caribbean by Tue. ATLANTIC OCEAN... A Gale Warning is in effect for the western Atlantic north of 29.5N and west of 78W beginning this afternoon due to Post- Tropical Cyclone Nestor. See section above for details. A warm front extends from Nestor to Tallahassee Florida to 30N80W to 27N75W. See Special Features section above for description of convection. A cold front extends from 31N58W to 27N64W to 25N70W. A large mid-upper level trough digs southward from the mid-latitudes to about 28N along 59/60W. Scattered moderate showers and isolated tstorms are seen from 25N-31N between 45W-62W. Farther E, an upper-level low is near 29N36W. Scattered showers and tstorms are from 26N-31N between 32W-39W. Post-Tropical Cyclone Nestor over the NE Gulf of Mexico will move NE across the SE United States this weekend. Nestor will generate gale force S to SW winds over the NW Atlc waters north of 29.5N and west of 78W this afternoon until early Sunday morning. Weak high pressure will prevail over the area Mon and Tue. A cold front will move off the coast of N Florida Tue evening. $$ Hagen

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