000 AXNT20 KNHC 181129 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 629 AM EST Sat Jan 18 2020 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 1110 UTC. ...SPECIAL FEATURES... See the latest NWS Highs Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC or at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for further details on the special features discussed below. ...SOUTH-CENTRAL CARIBBEAN GALE WARNING... The latest ASCAT pass from 18/0214 UTC shows gale force winds off Colombia from 10N-13N between 74W-78W. Expect gale-force winds to continue north of Colombia today and tonight diminishing to below gale force by late Sunday morning. Seas will range from 12 to 18 ft in this area. ...CENTRAL ATLANTIC GALE WARNING... A cold front extends from 32N47W to 25N57W to 23N63W to 22N71W to 24N82W, then continues as a stationary front to 27N88W. The latest set of ASCAT passes from 18 January between 0000-0200 UTC show gale force winds north 28N within 600 nm behind the front and within 240 nm ahead of the front. Gales will spread east with the front north of 28N through this evening. Seas will range from 16 to 23 ft near the front. ...GULF OF MEXICO GALE WARNING... A cold front will move into the NW Gulf of Mexico this evening and move eastward across the Gulf Sun into Mon. Behind the front, gale force N winds are expected in the far west-central Gulf offshore Tampico Sunday and Sunday night. Gales are also forecast in the far SW Gulf off Veracruz Sunday night into Mon. ...WESTERN ATLANTIC AND NORTHEAST CARIBBEAN LARGE SWELL... Large northerly swell in excess of 10 ft will combine with strong winds to produce significant wave heights in excess of 15 ft today over a large area of the Atlantic north of 21N between 48W-71W. Swell will affect the easternmost shores of the Bahamas today, then gradually diminish Sunday. By tonight, the large swell will begin to affect the north coast of Puerto Rico, Mona Passage, Virgin and Leeward Islands, and northeast Caribbean passages. The large swell will continue in these areas through Sunday night before gradually diminishing on Monday. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Liberia near 05N09W to 06N15W to 02N21W. The ITCZ continues from 02N21W to 01N34W to the coast of Brazil near 01S46W. Scattered moderate with isolated strong convection is noted near and within 180 nm north of the ITCZ between 27W-42W. Isolated moderate convection is elsewhere within 180 nm N of the ITCZ between 21W-44W. GULF OF MEXICO... A Gale Warning is in effect for the west-central and southwest Gulf of Mexico, with gale conditions beginning on Sunday. See section above for details. Mid-level ridging prevails over the southeastern Gulf of Mexico. A stationary front extends from the Dry Tortugas to 27N88W, then continues as a dissipating stationary front to 29N94W. Only isolated showers are along the front due to subsidence from the ridging. Strong E to SE winds around 25 kt are still being observed over the eastern portion of the basin, mainly east of 88W. As the front dissipates today, winds and seas should subside. A surface trough is in the far western Gulf from 18N94.5W to 24N97W. Scattered showers and isolated tstorms are near and north of the trough, including the area from 23N-26N between 95W-97.5W. A cold front will move off the Texas coast early this evening, then move SE, reaching from Clearwater Florida to the Bay of Campeche by Sun evening, and finally SE of the basin by early Mon. Strong N winds will follow this cold front, and gale conditions are expected to develop from offshore Tampico Mexico into the western Bay of Campeche Sun and Sun night. Offshore Veracruz, gales may persist through Mon night. CARIBBEAN SEA... Gale-force winds are noted over the south-central Caribbean off the coast of Colombia. Also, large northerly swell is expected for the northeast Caribbean passages on Sunday. See the sections above for details. Strong to near gale tradewinds prevail across the remainder of the basin west of 70W. Moderate trades are east of 70W. Isolated showers are seen near the Leeward Islands, Puerto Rico and Hispaniola as well as the adjacent waters. Isolated showers and tstorms are also seen over the Gulf of Honduras. The central Caribbean is experiencing relatively dry air due to mid-level ridging over the region. Elsewhere, a cold front that extends from the SE Bahamas to the Dry Tortugas is spreading cloudiness and showers along the north coast of Cuba. The pressure gradient between strong high pressure centered over the SE U.S. coast and low pressure over NW Colombia will continue to support gales off the coast of Colombia through Sun morning, with gale force winds again pulsing Sun night. This gradient will tighten further as the high surges south through tonight, leading to strong to near gale force winds over much of the central and northeast Caribbean into Sun. For most areas, winds and seas will diminish Mon and Tue, but a cold front will move into the NW Caribbean Mon evening, bringing strong N winds to areas W of 80W into Tue night. ATLANTIC OCEAN... A Gale Warning is in effect for the central Atlantic. Refer to the section above for details. A cold front extends from 32N47W to 25N57W to 23N63W to 22N71W to 24N82W, then continues as a stationary front to 27N88W. Scattered moderate with isolated strong convection is along and within 120 nm ahead of the front, north of 26N and east of 50W. Isolated to scattered moderate convection is within 120 nm behind the front, north of 28N and east of 50W. Aside from the gale force winds discussed in the section above, strong to near gale force winds are elsewhere north of 24N between 40W-88W. East winds of 25-30 kt are over the northwest and central Bahamas, the Florida Straits and the Florida Keys. Altimeter data from 18/0216 UTC indicates significant wave heights of 18 to 20 ft in the area from 28N-31N between 67W-70W. Surface ridging is over the far eastern Atlantic, anchored by a 1031 mb high near 34N13W. Upper-level troughing is producing cloudiness and scattered showers from 14N- 27N between 19W-34W. The cold front from 23N63W to 24N82W will stall over the Greater Antilles by this evening, then dissipate Sun. In its wake, strong northerly winds, some near gale force, will result, with large seas in northerly swell expected through Mon. Another cold front will move off the SE U.S. coast Sun afternoon, then move SE across the area through mid-week. Strong to near gale force N winds and building seas will follow in behind this front over the NW waters early next week. $$ Hagen