000 AXNT20 KNHC 052309 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Mon Sep 6 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 1800 UTC surface analysis and satellite imagery through 2230 UTC. ...SPECIAL FEATURES... Category 3 Hurricane Larry is centered near 20.5N 50.6W at 05/2100 UTC or 720 nm ENE of the Northern Leeward Islands moving NW at 11 kt. Estimated minimum central pressure is 955 mb. Maximum sustained wind speed is 110 kt with gusts to 135 kt. The eye diameter is 45 nm on IR satellite imagery. Numerous moderate to strong convection extends within 250 nm in the S semicircle and 200 nm in the N semicircle. Seas of 12 ft or higher extend 300 nm in the N semicircle, 210 nm in the SE quadrant and 240 nm in the SW quadrant, with seas peaking to 47 ft. On the forecast track, a northwestward motion with a slight decrease in forward speed is expected during the next few days. Little change in strength is forecast during the next few days, although fluctuations in intensity will be possible. However, Larry is expected to remain a major hurricane through the middle of this week. Swells generated by Larry are reaching the Lesser Antilles and are expected to spread westward to portions of the Greater Antilles, the Bahamas, and Bermuda on Monday and Tuesday. Significant swells should reach the east coast of the United States and Atlantic Canada by midweek. These swells are likely to cause life-threatening surf and rip current conditions. Please read the latest High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... An eastern Atlantic tropical wave has an axis along 21W from 18N southward, moving W at 10 kt. Scattered showers are noted from 06N to 09N between 18W to 23W. An Atlantic Ocean tropical wave has an axis along 37W from 16N southward, moving W at 5-10 kt. The wave is situated at the leading edge of a Saharan dust plume. As a result, no significant convection is noted with the wave at this time. A Caribbean Sea tropical wave has an axis along 77W from 19N southward, moving W at 10 kt. Scattered moderate convection is noted from 09N to 16N between 75W to 79W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends into the Atlantic Ocean off of the Mauritania/Senegal border near 16N17W to 07N28W. The ITCZ extends from 07N28W to 05N36W, then continues W of a tropical wave from 04N38W to 05N49W to the coast of Venezuela near 09N61W. Aside from the convection mentioned in the tropical waves section, scattered moderate convection is noted from 01N to 09N between 23W to 41W and from 02N to 08N between 44W to 49W. GULF OF MEXICO... A weakening stationary front extends north of Tampa Bay, Florida near 28N83W to the Mississippi coast near 30N89W. No significant convection is noted near this boundary. A trough extends across the central Gulf from 29N87W to 25N90W with scattered moderate convection near and east of this feature from 25W to 26W between 84W to 91W. A 1011 mb low is analyzed off the Yucatan coast near 20N91W with scattered moderate to isolated strong convection from 19N to 23N and E of 92W. High pressure dominates the rest of the Gulf anchored by a 1018 mb high pressure near 27N92W. Light to gentle winds prevail across the Gulf with seas 1 to 2 ft. For the forecast, the weak low pressure in the southwest Gulf is forecast to move slowly northward or northeastward over the central and then northeastern Gulf of Mexico over the next few days, when upper-level winds are only expected to be marginally conducive for tropical cyclone formation. The disturbance is then expected to cross the SE US beginning midweek, and some development is possible once it emerges over the Atlantic waters by late this week. This system has a low chance of development in the next 48 hours and 5 days. Elsewhere, a weakening stationary front over the northeast Gulf will dissipate later today, while high pressure dominates much of the remainder of the basin. CARIBBEAN SEA... See the Tropical Waves section above for details on a tropical wave in the central Caribbean. Scattered moderate convection continues across the western Caribbean from 10N to 23N between 78W and 83W. Isolated thunderstorms are noted in the central Caribbean S of 14N between 70W to 75W. Isolated thunderstorms are also SW of the Leeward Islands. Moderate to fresh tradewinds are noted across the central Caribbean with gentle to moderate winds in the western and eastern Caribbean. Seas are 3 to 6 ft across the basin with seas to 2 ft in the NW Caribbean. For the forecast, Major Hurricane Larry will remain well to the northeast of the Leeward Islands through Mon, then move farther north of the area through mid week. Associated rough seas east of Leeward Islands and Atlantic entrances will persist into Mon, then subside through mid week as Larry moves farther away. Elsewhere, gentle to moderate trade winds will persist, pulsing to fresh winds off Colombia mainly at night. ATLANTIC OCEAN... Attention remains focused of Major Hurricane Larry. Please see the Special Features section for details. A weakening stationary front extends across the SW N Atlantic from 31N74W to the central Florida coast near 28N80W. A trough extends across the central Bahamas from 27N76W to 22N77W. Scattered moderate convection is off the Florida coast and the northern Bahamas from 25N to 30N between 62W to 80W. High pressure extends across the central Atlantic anchored by a 1018 mb high near 26N62W and a 1020 mb near 26N37W. In the eastern Atlantic, a cold front extends from 31N21W to 31N37W with showers along the boundary. Outside of Hurricane Larry, gentle to moderate winds prevail across the basin with seas 3 to 6 ft. For the forecast, Major Hurricane Larry near 20.5N 50.6W 955 mb at 5 PM EDT moving NW at 11 kt. Maximum sustained winds 110 kt gusts 135 kt. Larry will move to 21.6N 51.9W Mon morning, 22.7N 53.4W Mon afternoon, 23.9N 54.8W Tue morning, 25.3N 56.2W Tue afternoon, 26.8N 57.5W Wed morning, and 28.5N 59.1W Wed afternoon. Larry will change little in intensity as it moves east of Bermuda early Thu. Large swell and rough seas generated by Larry will continue to propagate across waters northeast of the Leeward Islands and spread west of 65W by early Mon, the perhaps reach 70W by mid week. $$ AReinhart