000 AXNT20 KNHC 062332 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Tue Sep 7 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 2300 UTC. ...SPECIAL FEATURES... Hurricane Larry is centered near 22.5N 53.9W at 06/2100 UTC or 580 nm ENE of the Northern Leeward Islands moving NW at 9 kt. Estimated minimum central pressure is 956 mb. Maximum sustained wind speed is 110 kt with gusts to 135 kt. The large eye diameter is 65 nm on IR satellite imagery. Numerous moderate to strong convection is noted within 200 nm of the southern semicircle and scattered moderate to isolated strong convection is within 200 nm in the northern semicircle. Seas of 12 ft or higher extend outward 300 nm from the center except 330 nm in the NE quadrant with maximum seas to 44 ft. On the forecast track, Larry will continue moving northwest through Wednesday, followed by a turn toward the north-northwest and north on Thursday. Some fluctuations in intensity are possible during the next couple of days. Thereafter, some gradual weakening is forecast. Swells generated by Larry will continue to affect the Lesser Antilles, portions of the Greater Antilles, and the Bahamas through Tuesday, and Bermuda through late this week. Significant swells should reach the east coast of the United States and Atlantic Canada by midweek and continue affecting these shores through the end of the week. 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 Atlantic Ocean tropical wave has an axis along 26W from 19N southward, moving W at 15 kt. Scattered moderate convection is noted from 05N to 12N between 24W and 29W. An Atlantic Ocean tropical wave has an axis 48W from 15N southward, moving W at 20 kt. Isolated showers are noted within 50 nm of the wave. A Caribbean Sea tropical wave has an axis along 83W from 16M southward, moving W at 10 kt. Scattered moderate to isolated strong convection is noted S of 15N and W of 82W. The strongest convection associated with this wave is moving over Nicaragua and Honduras toward the Eastern Pacific. ...MONSOON TROUGH/ITCZ... The monsoon trough extends off the coast of Mauritania near 20N16W to 13N26W to 07N37W. The ITCZ continues from 07N37W to 05N46W, then continues W of a tropical wave near 05N48W to the coast of French Guiana near 05N52W. Aside from the convection mentioned in the Tropical Waves section above, scattered moderate convection is noted from 04N to 14N between 28W and 35W, from 05N to 08N between 38W and 45W, and from 05N to 10N between 49W and 52W. GULF OF MEXICO... A weak 1017 mb high pressure is centered in the southeast Gulf near 25N84W. A surface trough is noted in the Bay of Campeche from 24N91W to 19N94W. Scattered moderate to strong convection is noted in the Bay of Campeche and the central/southeastern Gulf from 20N to 27N between 83W and 93W, with the strongest thunderstorms noted within 100 nm of the trough. Gusty winds and rough seas are likely with these storms. Light to gentle winds are noted across the basin with seas to 2 ft. For the forecast, weak low pressure NW of the Yucatan Peninsula is forecast to move N or NE over the central and NE Gulf of Mexico over next few days, likely reaching the northern Gulf coast by mid-week. Upper-level winds are currently unfavorable for tropical development, but could become somewhat conducive for formation before it reaches the coast. Aside from this low pressure, high pressure will bring light to gentle winds and slight seas into mid-week. CARIBBEAN SEA... See the Tropical Waves section above for details on the tropical wave moving into the western Caribbean. A very modest pressure gradient across the basin between high pressure south of Bermuda and low pressure along the monsoon trough exiting NW Colombia is yielding moderate to fresh trade winds across the basin between 65W and 80W, where seas are generally 4 to 7 ft. Swell from distance hurricane Larry is beginning to enter Atlantic passages off the Leeward Islands, where seas are to 8 ft. For the forecast, Hurricane Larry will remain well to the northeast of the Leeward Islands tonight, then move farther north of the area through mid week. Associated moderate to large swell will continue to move into the region through mid week. Elsewhere, gentle to moderate trade winds will persist, pulsing to fresh winds off Colombia mainly at night. ATLANTIC OCEAN... Please see the Special Features section for details on Category 3 Hurricane Larry. A middle to upper level cyclone is located west of Larry, is centered near 22.5N 66W and nearly stationary. Associated upper level divergence associated with both of these features is supporting active scattered convection from 24N to 30N between 65W and 80W, where moderate SW to W winds are converging at the surface south of a weak trough from 31N69W to 30N77W. At the surface, weak high pressure is drapped across the north of Larry, with weak high center of 1017 mb near 25N66W. Thus, generally outside of Larry, light to gentle wind prevails with seas of 3 to 7 ft west of 66W. Some east swell will reach the SE Bahamas and adjacent waters to the north this evening. To the S and E of Larry, generally S of 20N and E of 50W, moderate to fresh NE trades prevail. A weakening cold front is noted in the northeast basin, from 30N14W to 25N26W to 30N40W. A trough is south of the front from 25N27W to 24N39W. No convection is associated with this front, and winds north of the boundary are N and gentle to moderate. Hurricane Larry near 22.5N 53.9W 956 mb at 5 PM EDT moving NW at 9 kt. Maximum sustained winds 110 kt gusts 135 kt. Larry will move to 23.4N 55.0W Tue morning, 24.9N 56.3W Tue afternoon, 26.5N 57.6W Wed morning, 28.3N 59.1W Wed afternoon, 30.4N 60.7W Thu morning. Larry will move north of the area near 33.1N 61.7W Thu afternoon. Large swell generated by Larry will continue to propagate across the eastern forecast waters, reaching 70W by mid week. $$ AReinhart