000 AXNT20 KNHC 081001 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Wed Sep 8 2021 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 0900 UTC. ...SPECIAL FEATURES... Major Hurricane Larry is centered near 26.5N 57.3W at 08/0900 UTC or 530 nm SE of Bermuda moving NW at 9 kt. Estimated minimum central pressure is 967 mb. Maximum sustained wind speed is 100 kt with gusts to 120 kt. Numerous moderate to strong convection is noted within 120 nm of the center, except for 150 nm in the NE quadrant. Larry is expected to move NW then N over the next 36 to 48 hours, with the center passing E of Bermuda on Thu. Gradual weakening is forecast over the next couple of days should bring Larry below major hurricane intensity, with more rapid weakening possible thereafter. Please, read the latest NHC Public Advisory at: https://www.nhc.noaa.gov/text/MIATCPAT2.shtml, and the Forecast/Advisory at: https://www.nhc.noaa.gov/text/MIATCMAT2.shtml, for more details. A surface trough in the Gulf of Mexico along 90W, in combination with an upper level disturbance, is leading to scattered, disorganized moderate convection N of 24N between 86W and 92W. This activity is expected to move NE over the NE Gulf of Mexico today. Upper-level winds could become slightly more favorable for tropical or subtropical development as the system nears the northern Gulf coast tonight or early Thu. The trough or possible low is then forecast to cross the SE U.S., and some additional development is possible after it emerges off the SE U.S. coast late this week. Regardless of development, areas of heavy rainfall may lead to localized flooding in portions of the Florida Panhandle and southern Georgia through Thu. There is a medium chance of tropical or subtropical formation in the next 48 hours. Please, read the Tropical Weather Outlook, at the following web address: https://www.nhc.noaa.gov/text/MIATWOAT.shtml for more details. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 22W, from the Cabo Verde Islands southward, moving W at around 10 kt. Scattered moderate convection is noted from 08N to 13N between 19W and 22W. An Atlantic Ocean tropical wave is along 37W, from 16N southward, moving W at around 10 kt. Scattered moderate convection is noted from 05N to 13N between 32W and 43W. An Atlantic Ocean tropical wave is along 58W, from 15N southward, moving W at 10 to 15 kt. Scattered moderate to isolated strong convection is noted from 07N to 09N between 48W and 58W. A tropical wave previously over Central America has moved into the eastern Pacific, with no further associated convection in the western Caribbean. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of Senegal near 15N17W to 10N27W to 07N37W. The ITCZ continues from 07N37W to 03N46W. Other than convection associated with the tropical waves mentioned in the section above, scattered moderate convection is noted from 04N to 09N between 43W and 46W. GULF OF MEXICO... Please see Special Features section above for details on a trough of low pressure with the potential for tropical development in the NE Gulf. Moderate to locally fresh SW winds are occurring in the vicinity of this trough, mainly between 85W and 92W. To the east of that, gentle southerly winds prevail, while to the west, winds are light and variable. Seas throughout the basin are generally 3 ft or less. For the forecast, the low pressure trough will move NE over the NE Gulf today, and upper level winds may become slightly more favorable for tropical or subtropical development as the system nears the northern Gulf coast tonight or early Thu. Regardless of development, heavy rain is possible across portions of the Florida Panhandle through Thu. CARIBBEAN SEA... The eastern extension of the eastern Pacific Ocean monsoon trough crosses Panama an Costa Rica along 10W and continues into Colombia. A fairly broad area of moderate convection is associated with this feature, S of 15N and W of 72W. Elsewhere across the basin, mainly moderate trades prevail with dry conditions, aside from a cluster of moderate trade wind thunderstorms in the vicinity of the Cayman Islands. Seas range from 4 to 6 ft. For the forecast, swells generated by Major Hurricane Larry will continue to propagate across the Atlantic waters of the Leeward Islands, Puerto Rico, and Hispaniola through Wed night. Seas will gradually subside from E to W. Elsewhere, mainly moderate trade winds will persist, pulsing to fresh to possibly locally strong winds off Colombia mainly at night. ATLANTIC OCEAN... Please see Special Features section above for details on Major Hurricane Larry and on the potential for low pressure to form in the NE Gulf and bring tropical development to areas offshore N Florida late this week. Outside of Larry, a weakening surface trough extends from 30N67W to 25N72W. Scattered moderate convection is noted N of 25N between 67W and 72W. High pressure dominates much of the rest of the basin, anchored by a 1016 mb center N of the NW Bahamas and a 1021 mb center near 33N30W. For areas W of the influence of Larry, gentle and variable winds prevail. To the E, and N of 20N, gentle to moderate E winds prevail, with areas S of 20N having moderate to fresh trades. Swell from Hurricane Larry encompasses a wide area of the basin, with 8 ft seas or greater occuring N of 20N between 50W and 70W. Elsewhere, seas average 4 to 6 ft. For the forecast, large swells generated from Major Hurricane Larry, passing well E of the area, will continue to propagate across area waters. Seas of 8 ft or more can be expected mainly E of 70W, spreading to 75W Thu, and potentially 80W Thu night. Low pressure may develop in the NE Gulf of Mexico tonight and cross the SE U.S. Thu. It could emerge into Atlantic waters Thu night or Fri. There is some potential of tropical or subtropical development while the system is in the NE Gulf, and additional potential off the N Florida or Georgia coast late this week. $$ KONARIK