000 AXNT20 KNHC 172305 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Mon Oct 18 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... Gulf of Mexico Gale Warning: A cold front extends from near Naples, Florida to near Coatzacoalcos, Mexico. Gale-force winds are active off Veracruz behind the front, with seas to 16 ft in the area of strongest winds off Veracruz. Winds and seas will decrease this evening, with winds diminishing below gale force. Marine conditions will continue to improve through early this week. Please read the latest High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details on both warnings. ...TROPICAL WAVES... The axis of a tropical wave is near 20W south of 17N, moving W at 10-15 kt. Scattered moderate convection is observed from 06N to 08N between 18W and 25W. The axis of a tropical wave is near 41W/42W south of 20N, moving W at 10-15 kt. Scattered moderate to isolated strong convection is observed from 07N to 09N between 37W and 44W. The axis of a tropical wave is near 55W south of 20N, moving W at 10-15 kt. Scattered moderate to isolated strong convection is noted from 18N to 20N betwen 50W and 53W, associated with a sharp upper trough north of the tropical wave. The axis of a tropical wave is near 75W south of 20N, moving W at 10-15 kt. No significant convection is observed near this wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough extends off the coast of Africa near 12N17W to 07N22W. Segments of the ITCZ extend from 07N22W to 06N30W to 09N40W, and from 08N43W to 05N51W. No significant convection is observed other that what was already mentioned in the Tropical Waves section. GULF OF MEXICO... Refer to the Special Features for information on the Gale Warning off the coast of Veracruz, Mexico over the SW Gulf of Mexico. A cold front extends from near Naples, Florida to near Coatzacoalcos, Mexico. Aside from the gale-force winds off the coast of Veracruz, Mexico, fresh to strong winds prevail west of the front. Seas west of the front are in the 8-12 ft range south of 25N, peaking to 16 ft off Veracruz. Seas are 5-8 ft elsewhere west of the front, and 2-4 ft east of the front. Scattered moderate convection is observed within 30 nm of the front between 85W and 90W, and along the coast of Mexico between 92W and 94W. For the forecast, winds across the Gulf will gradually veer to the E late Mon through Tue as the front becomes aligned from just offshore of the N Yucatan Peninsula through the Straits of Florida and dissipates. CARIBBEAN SEA... A weak pressure pattern prevails across the Caribbean waters. Scattered showers are noted in the western Caribbean and along the coast of Nicaragua and Costa Rica. Gentle to moderate winds, and seas of 2-4 ft, are noted over the central and eastern Caribbean waters south of 15N. Light to gentle winds, and seas of 1-3 ft prevail elsewhere across the Caribbean. For the forecast, the weak pressure gradient across the Caribbean basin will maintain tranquil marine conditions through early Mon. A cold front drifting over the southern Gulf of Mexico will stall north of the area from near 25N65W to the Straits of Florida. High pressure building in the wake of the front will bring a return to moderate trade winds to the Caribbean Mon night through Tue and then moderate to fresh winds late Wed. ATLANTIC OCEAN... A cold front extends across the Atlantic waters from 31N72W to West Palm Beach, Florida. Fresh to strong winds, and seas of 6 to 8 ft. Farther east, a cold front extends from 31N32W to 23N47W, with a trough continuing to near 22N70W. A sharp upper trough just to the northwest of these features is supporting scattered moderate convection is observed from 18N to 20N betwen 50W and 53W. Fresh to strong winds, and seas of 8-11 ft are also noted within 90 nm east of the front, north of 28N. Over the tropical waters south of 20N, moderate to fresh winds and seas of 4-6 ft prevail. N of 20N and east of 50W, gentle to moderate winds and seas of 5-8 ft prevail. Elsewhere over the tropical and subtropical waters north of 20N and west of 50W, light to gentle winds, and seas of 3-5 ft, prevail. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Moderate to high ash concentrations are observed west of La Palma moving north, along with light to moderate concentrations east of La Palma, Tenerife, and Gran Canaria. 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/ For the forecast west of 65W, the cold front will continue moving southeastward across most of Florida tonight, reaching from near Bermuda to the Straits of Florida by Mon morning. Expect fresh to strong N to NE winds behind the front through Mon morning. High pressure will shift ESE across the western Atlantic along 31N-32N Tue through Wed while the front stalls from near 25N65W to the Straits of Florida. $$ Christensen