000 AXNT20 KNHC 180601 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 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 0000 UTC surface analysis and satellite imagery through 0545 UTC. ...SPECIAL FEATURES... Gulf of Mexico Gale Warning: A cold front extends from southwest Florida to 22N90W and to the eastern Bay of Campeche. A tight gradient behind the front from high pressure that is building southward over eastern Mexico is producing northwest to north gale-force winds of 30-35 kt offshore Veracruz, Mexico along with peak seas of up to 15 ft. The gradient will slacken just enough to allow for these winds to diminish to just below gale force in just a few hours. 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 far eastern Atlantic tropical wave is near 21W/22W from 02N to 17N. It is moving westward at 10-15 kt. Scattered moderate convection is within 120 nm west of the wave from 08N to 10N. The axis of a central Atlantic tropical wave is near 43W from 02N to 19N, moving westward at 10-15 kt. Increasing scattered moderate to isolated strong convection is noted within 180 nm east of the wave axis from 08N to 10N. The latest CIRA LPW animation imagery indicates an enhancement of the atmospheric moisture in that same area. Scattered moderate convection is within 120 nm west of the wave axis from 05N to 06N. The axis of another central Atlantic tropical wave is near 56W south of 20N, moving westward at 10-15 kt. Scattered moderate convection is seen from 18N to 20N betwen 51W-54W, mainly associated with a sharp upper-level trough north of the tropical wave. The axis of a Caribbean Sea tropical wave is estimated to be near 76W south of 20N. It is moving westward at 10-15 kt. Small isolated showers and thunderstorms are within 60 nm E of the wave axis south of 13N. ...MONSOON TROUGH/ITCZ... The monsoon trough extends off the coast of Africa near 12N17W to 07N23W. Segments of the ITCZ extends from 07N23W to 08N43W and also from 08N44W to 06N50W. In addition to the convection mentioned above in the Tropical Waves section, scattered moderate to isolated strong convection is south of the ITCZ from 05N to 08N between 35W-39W. Scattered moderate convection is within 120 nm south of the ITCZ between 45W-47W. GULF OF MEXICO... Refer to the Special Features for information on the Gale Warning in the far SW Gulf of Mexico off the coast of Veracruz, Mexico. A cold front extends from southwest Florida to 22N90W and to the eastern Bay of Campeche. Aside from the gale-force winds offshore the coast of Veracruz, Mexico, fresh to strong winds prevail west of the front. Seas west of the front are in the 8-13 ft range south of about 22N, except peaking to 15 ft off Veracruz. Seas are 5-7 ft elsewhere west of the front, and 2-4 ft east of the front. Scattered showers and a few thunderstorms are over the extreme southern Bay of Campeche south of 19N and between 94W-95W. For the forecast, the aforementioned cold front will continue moving southeastward through Mon. Winds off of Veracruz, Mexico are expected to diminish through Mon. Winds across the Gulf will gradually veer to the east late Mon through Tue as the front becomes aligned from just offshore of the northern Yucatan Peninsula through the Straits of Florida and dissipates. CARIBBEAN SEA... A weak pressure pattern prevails across the Caribbean waters. Scattered showers and thunderstorms are occurring well inland Nicaragua and over southwestern Honduras. Similar activity is over the eastern section of Haiti. Otherwise, small isolated showers and thunderstorms are over some areas of the western Caribbean and over the northeastern Caribbean within about 90 nm south of Puerto Rico. 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 lead to tranquil marine conditions through Mon. A cold front across the NW Atlantic will move southeastward 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 Mon night through Tue and then moderate to fresh winds late on Wed. ATLANTIC OCEAN... A cold front extends across the Atlantic waters from near 31N71W to South Florida. Fresh to strong north to northeast winds as were revealed in a recent ASCAT are behind the front. Seas with these winds are in the range of 6-8 ft. Farther east, a cold front extends from near 31N32W to 25N42W, then becomes stationary to 23N47W and transitions to a trough to near 20N54W. A weak trough is east of the cold front along a position from 29N27W to 23N35W. No significant convection is noted. A sharp mid to upper- level trough just to the northwest of these features is supporting scattered moderate convection observed from 15N to 20N betwen 52W- 57W. Mainly fresh southwest winds and seas of 8-9 ft in a southwest swell are also noted within 180 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 remain there. 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. 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 that extends from near 31N71W to South Florida will will continue moving southeastward reaching from near Bermuda to the Straits of Florida this morning. Expect fresh to strong north to northeast winds behind the front through this morning. High pres will shift east-southeastward across the western Atlantic along 31N-32N Tue through Wed while the front stalls from near 25N65W to the Straits of Florida. $$ Aguirre