000 AXNT20 KNHC 061746 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Wed Oct 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 1200 UTC surface analysis and satellite imagery through 1700 UTC. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 25W, from 16N southward, moving W at 20 kt. Scattered moderate showers are found where the wave axis intersects the ITCZ, from 01N-05N. An Atlantic Ocean tropical wave is along 50W, from 18N southward, moving W at 20 kt. Scattered moderate and isolated strong convection is noted over a large area along and east of the wave axis, from 05N-14N between 41W-53W. The convection is being enhanced by strong upper-level divergence to the east of an upper-trough. Satellite imagery suggests that dry Saharan Air accompanies this wave, north of 13N between 55W and 25W. A Caribbean Sea tropical wave is along 82W, from 17N southward, moving W near 10-15 kt. Scattered moderate to strong convection covers the area from 09N-20N between 80W-85W, and from 09N-13N between 76W-80W. Periods of heavy rainfall are possible over portions of Nicaragua and Costa Rica through Thursday night. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of Guinea-Bissau near 12N16W to 09N17W. The ITCZ extends from 09N17W to 05N19W to 08N44W to 07N58W. Aside from the convection mentioned above, scattered moderate isolated strong convection is noted from 03N-07N between 12W-22W, and from 03N-11N between 32W-41W. GULF OF MEXICO... A stationary front extends from Mobile, Alabama to a 1015 mb low near 29N88W to Veracruz Mexico near 19N96W. Scattered moderate and isolated strong convection is noted within 270 nm east of the front and north of 24.5N, especially in the waters off the Big Bend of Florida. Scattered moderate showers are also near the front over the western Bay of Campeche south of 21N and west of 93W. A weak high pressure ridge behind the front and across NE Mexico is promoting gentle to moderate northerly winds behind the front, except for fresh winds across the Veracruz area, where peak seas are 5 ft. Elsewhere E of the front, gentle to moderate SE to S winds prevail, except for fresh within the convection over the NE Gulf of Mexico. Seas are 1 to 3 ft over the eastern Gulf. The stationary front will meander through Thu before dissipating. Weak high pressure to the NW will support moderate to locally fresh northerly winds over Veracruz adjacent waters through Thu and fresh to locally strong winds over the NE Gulf through early this evening. High pressure will build modestly across the basin during the weekend. CARIBBEAN SEA... Strong convection over the western Caribbean Sea is described above in the tropical waves section. Water vapor imagery shows much drier air over the eastern half of the basin, especially between 60W-70W. The latest ASCAT wind data shows strong trade winds over the central Caribbean from 11N-16N between 72W-78W, where seas are likely 7 to 9 ft. Moderate to fresh winds prevail elsewhere north of 10N and east of 85W, where seas are 4 to 6 ft. High pressure currently NE of Bermuda will continue to support fresh trade winds across the eastern, central and southwest basin with locally strong winds along Hispaniola adjacent waters and the south-central Caribbean. These winds and seas to 8 ft will diminish Thu evening as the ridge slides ENE and a weaker pressure gradient establishes across the area. Moderate to locally fresh trades will dominate these regions Thu night through Sun. ATLANTIC OCEAN... A surface trough off the southeast U.S. coast extending from 33N73W to 26N79W is moving slowly NW. Recent buoy and ASCAT wind data indicate that a weak area of low pressure is developing along the trough about 150 nm east of the northeastern coast of Florida. Disorganized scattered moderate showers and isolated tstorms are noted from 28N-31N between 70W-79W. Upper-level winds are forecast to remain unfavorable for tropical cyclone development while the low moves slowly northward and then northeastward off the southeastern United States coast during the next few days. The system has a low chance of formation during the next 48 hours. A 1026 mb high pressure is centered just east of Bermuda. The gradient between this high pressure and 1009 mb low pressure along the coast of NW Colombia is producing fresh E winds across the southeast Bahamas and north of Hispaniola, where seas are 7 to 9 ft. Gentle to moderate winds cover the area north of 25N between 60W and Florida, where seas are 4 to 6 ft. Fresh to locally strong trade winds will continue south of 25N through Thu. Moderate to locally fresh winds will then gradually diminish to gentle to moderate Fri and continue through the weekend. Northerly swell generated from Sam east of 72W will diminish through tonight. Farther east, a surface trough associated with the remnants of Victor is producing scattered moderate and isolated strong convection from 23N-27N between 49W-56W. ASCAT data show fresh NE to E winds within the area of convection. East of 40W, broad surface ridging prevails. ASCAT shows fresh trade winds across the tropical Atlantic from 10N-20N, where seas are 6 to 7 ft. Saharan air is dominating the zone north of 13N between 25W and the tropical wave along 50W. The Cumbre Vieja volcano, located on the island of La Palma in the Canary Islands, has been erupting almost continuously since 19 September. Marine and aviation interests should monitor this ongoing situation by reading the Volcanic Ash Advisory issued by Meteo-France at http://vaac.meteo.fr/volcanoes/la-palma/ $$ Hagen