000 AXNT20 KNHC 150551 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 151 AM EDT Sun Sep 15 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 0000 UTC surface analysis and satellite imagery through 0530 UTC. ...SPECIAL FEATURES... Tropical Storm Humberto is centered near 27.6N 77.3W at 15/0300 UTC, or 75 nm N of Great Abaco Island, moving NNW at 5 kt. Estimated minimum central pressure is 1000 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Numerous moderate to scattered strong convection extends outward from the center 150 nm NE quad, 210 nm SE quad and 105 nm NW quad, with no convection in the SW quad. On the forecast track, the center of Humberto should continue to move well offshore of the east coast of Florida during the next day or so and then move away from the U.S. Humberto is forecast to become a Hurricane by tonight. Please read the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC, or at the website hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave has been added to the map in the eastern Atlantic along 19W from 18N southward, moving W around 15 kt. The wave shows up well in 700 mb trough diagnostics and TPW imagery. Scattered moderate convection is from 12N-18N between 16W-23W. Scattered showers are from 05N-12N between the wave axis and 25W. A tropical wave with axis along 38W from 05N-15N, is moving W around 15 kt. The wave is well depicted in satellite imagery and TPW imagery. Scattered moderate convection is from 07N-12N between 35W-42W. Conditions are forecast to be conducive for gradual development through the middle of next week and a tropical depression could form while the system moves slowly westward or west-northwestward. A central Atlantic tropical wave with axis along 51W from 07N- 21N is moving W around 20 kt. This wave is well depicted in model guidance and satellite imagery. Scattered showers are from 07N- 20N between 45W-56W. A tropical wave is currently over the Lesser Antilles, with axis extending from 20N59W to 06N62W, moving west around 10-15 kt. Scattered moderate convection is over the Lesser Antilles from 13N-18N between 60W-64W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from Guinea-Bissau near 12N16W to 08N42W. Aside from the convection already discussed in the Tropical Waves section above, scattered showers are noted within 180 nm N and 150 nm S of the monsoon trough between 20W-42W. GULF OF MEXICO... The weather over the Gulf of Mexico is dominated by a large mid to upper-level low that is centered over the central portion of the basin near 25N91W. The GFS model analysis and 6-hr forecast indicates that the low is closed from 250-500 mb, and there is a sharp trough at 700 mb. There is a weak low-level trough too, but the low-level trough is still more subtle at this time. Upper- level diffluence and divergence on the east side of the upper-low are enhancing scattered to numerous moderate convection from 24N- 29N and east of 92W. Scattered showers and isolated tstorms are from 25N-29N between 92W-95W. Some slow development of this system is possible during the next couple of days while it moves westward over the western Gulf of Mexico. The system is forecast to move inland along the northwestern Gulf coast by late Monday or Tuesday, and further development is not expected after that time. The latest ASCAT pass depicts fresh easterly winds across the northern half of the basin north of 24N, while gentle winds prevail south of 24N. Moderate to fresh east to northeast winds are expected across the northern Gulf through Mon associated with the area of low pressure. CARIBBEAN SEA... A tropical wave is currently producing scattered moderate showers and thunderstorms over the Lesser Antilles. See the Tropical Waves section for details. Mid-level anti-cyclonic flow is over Cuba and Jamaica, and relatively dry air covers the central Caribbean. A W-E surface trough is over western Cuba with isolated to scattered showers over Cuba. In the SW Caribbean, scattered moderate convection is over E Nicaragua and over water within 60 nm east of the coast of Nicaragua. Scattered showers are elsewhere southwest of a line from 10N75W to 15N83W. Scattered showers and tstorms are seen over the eastern Dominican Republic and over water from 15N-16.5N between 70W-73W. The latest ASCAT pass depicts fresh to strong trades in the south-central Caribbean. Moderate to fresh trade winds will dominate much of the basin, with fresh to strong winds in the south-central Caribbean through today. A tropical wave moving across the eastern Caribbean today will reach the central Caribbean on Monday. A second, stronger tropical wave will approach Barbados late today, 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 from a large, storm-force mid- latitude low currently centered near 40N46W, will reach the Atlantic passages into the Caribbean Sea late on Monday and continuing into mid-week. ATLANTIC OCEAN... Refer to the sections above for details on T.S. Humberto and the tropical waves moving across the basin. A surface trough over western Cuba is producing scattered showers and isolated tstorms over central and western Cuba as well as the Florida Straits. A mid to upper-level low near 26N57W is enhancing scattered showers and isolated tstorms from 20N-30N between 54W- 64W. A cold front extends over the discussion area from 32N47W to 31N54W to 32N64W. Scattered showers are south of the front. A surface trough extends from 30N43W to 25N51W. Scattered showers and tstorms are mainly east of the trough axis from 25N-31N between 38W-48W. The remainder of the eastern Atlantic is under surface ridging. Tropical Storm Humberto is near 27.6N 77.3W, 1000 mb, at 11 PM EDT moving NNW at 5 kt. Maximum sustained winds are 50 kt with gusts of 60 kt. Humberto is forecast to become a hurricane this evening near 29N78W, move to near 31N72W by Tuesday evening as a 90 kt hurricane, to near 33N66W Wed evening and near 37N59W Thu evening. Northerly swell from a large, storm-force mid-latitude low currently centered near 40N46W, will reach the Atlantic passages into the Caribbean Sea late on Monday and continuing into mid- week. $$ Hagen