000 AXNT20 KNHC 060512 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 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 0000 UTC surface analysis and satellite imagery through 0500 UTC. ...SPECIAL FEATURES... Hurricane Larry is centered near 21.0N 51.4W at 06/0300 UTC or 685 nm ENE of the northern Leeward Islands, moving NW at 10 kt. Estimated minimum central pressure is 955 mb. Maximum sustained wind speed is 110 kt with gusts to 135 kt. The eye diameter is 40 nm on IR satellite imagery. Numerous moderate to strong convection is within 180 nm of the center. The most recent ASCAT pass from Sunday evening around 07/0000 UTC shows that the area of winds over 20 kt associated with Larry's circulation extends outward 300 nm from the center, except only 210 nm in the SW quadrant. This encompasses most of the area from 17N-26N between 45W-56W. Seas of 12 ft or higher extend 300 nm in the N semicircle and 240 nm in the S semicircle, with seas peaking at 46 ft. On the forecast track, a northwest motion with a slight decrease in forward speed is expected during the next few days. Little change in strength is forecast during the next day or so, followed by very gradual weakening. 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 later today 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 currents. 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 23/24W from 19N southward, moving W at 15 kt. Isolated moderate convection is noted near the wave axis over portions of the Cabo Verde Islands. Scattered moderate convection is seen from 06N-09N within 180 nm of the wave axis. A central Atlantic Ocean tropical wave has an axis along 39/40W from 17N southward, moving W at 10 kt. The wave is situated at the leading edge of a Saharan dust plume. As a result, only isolated moderate convection is noted along and within 150 nm E of the wave axis from 04N-06N. A Caribbean Sea tropical wave has an axis along 78W from 19N southward through eastern Panama, moving W at 10 kt. Isolated to scattered moderate convection is within 150 nm either side of the wave axis south of 14N. Convection farther north near eastern Cuba is more related to upper-level diffluence than to the tropical wave. ...MONSOON TROUGH/ITCZ... The monsoon trough extends into the Atlantic Ocean off the coast of northern Senegal near 16N17W to 06N32W. The ITCZ extends from 06N32W to 05N38W, then continues W of a tropical wave from 04N42W to 06N52W to 09N61W. Aside from the convection mentioned above, scattered moderate and isolated strong convection is noted from 03N-06N between 29W-33W. Isolated to scattered moderate convection is from 04N-08N between 46W-51W. GULF OF MEXICO... A weak 1010 mb low along a surface trough is analyzed just off the west coast of the Yucatan Peninsula near 20N91W. The surface trough extends NNE from the low to near 24N89W. A recent ASCAT pass shows fresh to strong SE winds on the NE side of the low from 20N-23N between 89W-91W. Scattered moderate convection is noted from 19N to 25.5N between 85.5W and 91W, including over the Yucatan Peninsula. Numerous moderate and scattered strong convection is seen mainly inland over the Mexican states of Veracruz, Oaxaca and Puebla due to unstable conditions and a divergent pattern aloft in the area, but scattered tstorms extend over the SW Bay of Campeche, mainly south of 22N and west of 95W. Weak surface high pressure ridging prevails elsewhere across the Gulf of Mexico, anchored by a 1014 mb high pressure near 28N94W and a 1016 mb high pressure near Key West Florida. A recent ASCAT pass shows light to gentle winds over most of the area north of 24N. Seas of 1 to 3 ft prevail across the basin, except locally up to 4 ft off the NW coast of Yucatan. For the forecast, the weak low pressure in the southwest Gulf is forecast to move slowly N or NE over the central and NE Gulf of Mexico over the next few days. Upper-level winds could become marginally conducive for tropical cyclone formation by late Tue, before the system moves inland over the SE U.S. mid-week. The chance of formation in the Gulf is low with this system. Aside from the small low pressure system, high pressure will dominate the remainder of the basin early this week. CARIBBEAN SEA... See the Tropical Waves section above for details on the tropical wave along 78W. A diffluent pattern aloft is inducing scattered moderate and isolated strong convection over eastern Cuba and the waters just south of eastern Cuba. Scattered moderate showers are seen across other portions of the western Caribbean Sea, including the Yucatan Channel and the area just east of northern Nicaragua and E Honduras. The eastern Caribbean is drier, although isolated showers and tstorms are seen in the waters near Guadeloupe, Antigua and Montserrat. A recent ASCAT pass shows fresh trades in the central Caribbean between 67W-78W, from 12N-17N, where seas are 4 to 6 ft. Gentle to moderate winds prevail elsewhere with 2 to 4 ft seas. For the forecast, major Hurricane Larry will remain well to the northeast of the Leeward Islands through tonight, then move farther north of the area through mid week. Large swell affecting the Atlantic side of the Leeward Islands, Virgin Islands, Puerto Rico, Dominican Republic and the NE Caribbean passages will peak through tonight, then gradually subside into mid-week. Elsewhere, gentle to moderate trade winds will persist, pulsing to fresh off Colombia mainly at night. ATLANTIC OCEAN... Attention remains focused of Major Hurricane Larry. Please see the Special Features section for details. A weak pressure pattern prevails over the western Atlantic, leading to light to gentle winds across much of the area west of 72W. A diffluent pattern aloft is inducing scattered moderate and isolated strong convection over eastern Cuba and the Old Bahama Channel from 21N-24N between 76W-80W. Surface high pressure of 1020 mb is analyzed at 27N61W. To the west of this high pressure, an upper-level divergent pattern is inducing scattered moderate rain showers from 25N-29N between 67W-71W. To the northeast of Hurricane Larry, another 1020 mb surface high pressure is analyzed at 27N40W. In the NE Atlantic, a weak cold front extends from 31N20W to 28N28W to 31N37W, but no significant rain or winds accompany the front. Aside from the circulation of Hurricane Larry, gentle to moderate winds prevail across the remainder of the Atlantic. For the forecast, Hurricane Larry will move to near 23N54W this evening, near 26N57W Tue evening, and to near 29N60W Wed evening. Larry will then turn northward, remaining east of Bermuda. Large swell generated by Larry will continue to propagate across waters northeast of the Leeward Islands and spread west of 65W early today. Swell from Larry will reach the Bahamas Tue and the east coast of the U.S. by Wed. $$ Hagen