000 AXNT20 KNHC 181720 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 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 1200 UTC surface analysis and satellite imagery through 1700 UTC. ...TROPICAL WAVES... The axis of a tropical wave is near 25W from 02N to 14N, moving westward at 10-15 kt. Scattered moderate convection is from 10N to 13N between 20W and 28W. The axis of a tropical wave is near 45W from 02N to 16N, moving westward at 10-15 kt. Scattered showers are from 05N-10N between 40W-45W. The axis of a tropical wave is near 59W south of 16N, moving westward at 10-15 kt. No significant convection is noted at this time with this wave. The axis of a tropical wave is near 81W south of 17N, moving westward at 10-15 kt. Scattered moderate convection is noted from 15N-18N between 79W-84W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends off the coast of Africa near 17N16W to 07N24W. The ITCZ continues from 06N30W to 06N43W, then resumes near 06N47W to 05N53W. In addition to the convection mentioned above in the Tropical Waves section above, scattered moderate convection is observed from 04N to 10N between 33W and 52W. GULF OF MEXICO... A stationary front extends across the southern portion of the basin from 25N80W to 21N91W to 17N93W. Scattered moderate convection is noted within 100 nm N of the front mainly W of 87W. Latest scatterometer data depicts moderate to fresh winds within 200 nm N of the front. Seas range between 8-11 ft across the SW Gulf, while 4-7 ft prevail elsewhere. High pressure is building across the remainder of the basin in the wake of the front, centered near 22N97W. For the forecast, the will drift across the southern Gulf through Tue. Winds off of Veracruz, Mexico are expected to diminish today. By late Tue, winds across the Gulf will gradually veer to the E as the front becomes aligned from just offshore of the N Yucatan Peninsula through the Straits of Florida and dissipates. Weak high pressure will dominate the basin for the remainder of the week. CARIBBEAN SEA... Refer to the section above for details on the tropical wave moving across the basin. A weak pressure pattern prevails across the Caribbean waters. Light to gentle winds and seas of 1-3 ft prevail across much of the Caribbean waters. For the forecast, a persistent weak pressure gradient across the Caribbean basin will maintain tranquil marine conditions today. A cold front across the NW Atlc will move SE through early Wed before stalling 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 tonight through Tue and then moderate to fresh winds late Wed through Fri. ATLANTIC OCEAN... Refer to the section above for details on the tropical waves moving across the basin. A cold front extends across the Atlantic waters from near 31N64W to 25N80W. Moderate to fresh northerly winds are noted behind the front. Seas with these winds are in the 6-8 ft range. Gentle to moderate winds prevail within 400 nm SE of the front. Farther east, another cold front extends from near 31N21W to 27N35W, then becomes stationary from that point to 25N42W. A surface trough extends from 25N43W to 21N53W. Scattered moderate convection is observed within 120 nm SE of the cold front. Elsewhere over the tropical and subtropical waters north of 20N, light to gentle winds prevail. Seas are in the 6-7 ft range north of 26N and between 27W and 40W, and 3-6 ft elsewhere over the open waters north of 20N. Over the tropical waters south of 20N, gentle to moderate winds and seas of 4-6 ft prevail. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Light to moderate volcanic ash is expected in the area east of the volcano, while high ash concentrations are close to the volcano. 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 over the W Atlantic will continue moving slowly SE and stall along 23N-24N by late Wed. Expect fresh to strong N to NE winds behind the front through this morning. High pres will shift ESE across the W Atlantic along 31N-32N Tue through Thu while the front stalls and weakens. $$ ERA