000 AXNT20 KNHC 142340 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 740 PM EDT Sat Sep 14 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 2330 UTC. ...SPECIAL FEATURES... Tropical Storm Humberto is centered near 27.4N 77.3W at 14/2100 UTC, or 60 nm N of Great Abaco Island, moving NNW at 6 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 45 kt with gusts to 55 kt. Scattered to numerous moderate convection extends from 23N-30N between 71W-80W. On the forecast track, the center of Humberto should continue to move away from the northwestern Bahamas tonight, and then move well offshore of the east coast of Florida this weekend and early next week. Humberto is forecast to become a Hurricane by Sunday night well east of the east coast of Florida. Please read the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC, or go to the website hurricanes.gov for more details. ...TROPICAL WAVES... A central Atlantic tropical wave with axis along 36W from 05N- 15N, is moving W at 10-15 kt. The wave is well depicted in satellite imagery and TPW imagery. Scattered moderate convection is from 09N-12N between 32W-36W. Gradual development of this system is possible during the next several days, and a tropical depression could form early next week while it moves westward across the tropical Atlantic. A central Atlantic tropical wave with axis along 50W from 08N- 21N, is moving W at 15-20 kt. Scattered showers are within 180 nm west of the wave axis from 12N-20N. This wave is well depicted in model guidance and satellite imagery. A tropical wave is approaching the Lesser Antilles, with axis extending from 20N58W to 07N60W, moving west around 10-15 kt. Scattered showers are noted along the wave axis mainly north of 16N. This wave is well depicted in satellite and model guidance also. The northern extension of a tropical wave is currently over the Yucatan Peninsula with axis along 89W and south of 19N, moving W around 10 kt. Scattered showers are noted within 75 nm on either side of the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from Guinea-Bissau near 12N17W to 07N43W. A surface trough was noted in scatterometer data from 11N55W to 06N53W. Aside from the convection already discussed in the Tropical Waves section above, scattered showers are noted within 90 nm to the north of the monsoon trough. GULF OF MEXICO... The weather over the Gulf of Mexico is dominated by a large upper-level low that is centered over the central portion of the basin near 25N91W. Upper-level diffluence on the east side of the upper-low is producing numerous moderate convection from 24N-29N and east of 92W. Only slow development of this system is likely during the next couple of days while it moves westward over the western Gulf of Mexico. This system is forecast to move inland along the northwestern Gulf coast by late Monday or Tuesday and development is not expected after that time. The latest ASCAT pass depicts moderate to fresh easterly winds across the northern half of the basin, while light to gentle winds prevail over the southern half. Winds and seas will diminish tonight into Sun as Humberto moves away from the eastern coast of Florida. CARIBBEAN SEA... Refer to the Tropical Waves section above for details on the tropical waves moving and approaching the basin. Relatively dry air covers much of the Caribbean. In the SW Caribbean, a line of scattered moderate convection extends from the northwest coast of Colombia to the coast of Nicaragua, from 10N-16N between 78W-83W. A surface trough extends across the Yucatan Channel with scattered showers. Scattered showers are also noted over the northeast Caribbean due to an approaching tropical wave. The latest ASCAT pass depicts gentle to moderate trades across the basin. Moderate to fresh trade winds will pulse across the basin, with fresh to strong winds in the south-central Caribbean through Sun. A tropical wave will move across the eastern Caribbean tonight and Sun, reaching the central Caribbean on Mon. A third and stronger tropical wave will approach Barbados late on Sun, move across the eastern Caribbean Mon, and into the central Caribbean through mid week, bringing widespread showers and thunderstorms, gusty winds and building seas. Northerly swell will reach the Atlantic passages into the Caribbean Sea late on Mon. ATLANTIC OCEAN... Refer to the sections above for details on T.S. Humberto and the three tropical waves moving across the basin. Upper-level troughing covers the area from 23N59W to 31N53W. Upper- level diffluence near the base of this trough is enhancing convection north of 20N between 50W-65W. A surface trough was noted in scatterometer data from 28N61W to 23N66W. To the east, a 1018 mb high is centered near 28N46W. Surface ridging and fair weather covers the east Atlantic north of 20N and east of 40W. Tropical Storm Humberto will move to 28.2N 77.9W Sun morning, 29.3N 78.3W Sun afternoon, strengthen to a hurricane near 29.9N 77.9W Mon morning, 30.5N 76.7W Mon afternoon, and 31.2N 73.5W Tue afternoon. Humberto will change little in intensity as it moves near 32.5N 67.5W Wed afternoon, and continue to 36.0N 61.0W Thu. The center of Humberto should continue to move away from the northwestern Bahamas tonight, and then move well offshore of the east coast of Florida this weekend and early next week. Humberto is forecast to become a hurricane by Sunday night or early Monday well east of the east coast of Florida. Northerly swell will reach the Atlantic passages into the Caribbean Sea late on Mon. $$ ERA