000 AXNT20 KNHC 290915 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Fri Oct 29 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 0600 UTC surface analysis and satellite imagery through 0800 UTC. ...SPECIAL FEATURES... Gulf of Mexico Gale Warning: Strong to gale force W to NW winds are found north of 27N behind a strong cold front that stretches from near Naples, Florida to the western tip of Cuba and through the Yucatan Channel. Large seas of 8 to 18 ft cover much of the waters north of 25N in W to NW swell. A line of strong thunderstorms is accompanying the front. The front will push southeast of the basin later this morning. Winds will diminish below gale force this evening, then will diminish to gentle to moderate Sat night. The large NW swell will spread southeast, gradually decaying through the weekend. Please see the latest NWS High Seas Forecast issued by the National Hurricane Center at website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for further details. ...TROPICAL WAVES... A tropical wave is in the Atlantic Ocean along 30W from 03N to 18N, moving W at around 10 kt. Any nearby convection is described in the next section. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near Sierra Leone at 08N13W to 09N27W to 1012 mb low pressure near 07N32W to 05N39W. The ITCZ extends from 05N39W to 08N53W. Scattered moderate and isolated strong convection is from 11N to 13N between the coast of Africa and 25W, from 02N to 09N between 10W and 32W, and from 07N to 09N between 47W and 50W. The eastern Pacific Ocean monsoon trough extends across Costa Rica and just north of Panama along 10N through 1010 mb low pressure near 12N76W to the northern coast of Colombia near 11N74W. Scattered moderate to strong convection is occurring over far NW Venezuela near the border with Colombia, and across much of northern Colombia and eastern Panama. ...GULF OF MEXICO... Please see the Special Features section for more information on gale force winds and dangerous seas across the northern Gulf of Mexico behind a strong cold front. Outside of the area of strong to gale force winds, moderate to fresh winds cover the remainder of the waters west of the front to 94W, with light to gentle winds south of 25N and west of 94W where a ridge of high pressure is building in the wake of the front. Seas of 4 to 7 ft prevail outside of the strong to gale force winds. For the forecast, conditions will really improve Sun as ridging dominates from near the Texas-Louisiana border to the Bay of Campeche with light to gentle winds across the basin. Remnant NW swell will still be trickling down through the end of the weekend. The orientation of the ridge will shift early next week with more typical NE-E flow over the eastern half of the basin and E-SE flow over the western half of the basin at gentle to moderate levels. Seas of 3 ft or less are expected for the start of next week. ...CARIBBEAN SEA... Refer to the Monsoon Trough/ITCZ section for convection in the SW Caribbean. A cold front has breached the NW Caribbean extending from near the western tip of Cuba to northern Belize and across the Yucatan Peninsula. A line of thunderstorms is ahead of the front north of 21N to across western Cuba, with additional activity noted in the Gulf of Honduras to across portions of the Yucatan Peninsula and into Guatemala. Moderate to fresh NW-N winds have filtered in behind the front, while NW swell will quickly build to greater than 8 ft by the afternoon. Ahead of the front, light to gentle E-SE flow is west of 80W, with moderate to locally fresh E-SE flow east of 80W, except light and variable winds in the SW Caribbean outside of any convection. Seas are mainly 2 to 4 ft across the western Caribbean, 4 to 6 ft in the central Caribbean where winds are the strongest, near fresh, and 3 to 5 ft in the eastern Caribbean. For the forecast, the cold front will move through the NW Caribbean into the weekend, before stalling from the Windward Passage to northern Nicaragua Sun. Moderate to fresh NW winds and seas of up to 12 ft can be expected in the wake of the cold front, especially in and near the Yucatan Channel. Elsewhere, a weak ridge over the northern Caribbean Sea ahead of the front will support mainly gentle to moderate trade winds across the basin, with locally fresh winds possible in the Gulf of Honduras and off the coast of Venezuela. ...ATLANTIC OCEAN... A cold front extends from 31N79W to the Space Coast of Florida. A broken line and clusters of scattered showers and thunderstorms with plentiful lightning are ahead of the front. Fresh to strong SW winds are also ahead of the front from the Straits of Florida to along the Gulf stream, continuing east of Florida to 76W and off the coast of the Carolinas. Seas are 7 to 10 ft across this same area. Gentle to moderate winds prevail elsewhere ahead of the front with a ridge of high pressure extending into the area from the central Atlantic along 22N. Seas of 7 to 10 ft in NE swell covers the remainder of the waters north of 27N, with 4 to 7 ft south of 27N and east of the Bahamas. Another cold front is in the tropical Atlantic, from 31N55W to 25N67W. A line of scattered showers and thunderstorms is noted within 75 nm southeast of the front along with fresh to strong SW winds. Moderate to fresh winds follow the front to 65W. 1020 mb high pressure is located west of the Canary Islands near 29N21W with a ridge extending through 24N50W to along 22N near 65W. Moderate to fresh trades are noted from 11N to 23N east of 35W to the coast of Africa, with mainly light to gentle winds across the remainder of the tropical Atlantic waters. Seas of 4 to 7 ft in mixed swell prevail across the waters east of 65W, except 8 to 12 ft in northerly swell north of 27N and west of 45W. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. A volcanic ash cloud is slowly drifting southwest. High volcanic ash concentration remains in the vicinity of 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 55W, the cold front will gradually reach a Bermuda to Windward Passage line over the weekend. Fresh to strong winds are expected on both sides of the front through Sat, mainly north of 26N. Seas of 8 ft or greater will fill across the northern waters today, lingering through Sun before decaying. The front will weaken as it stretches from 30N65W to the Turks and Caicos Islands early Mon with gentle to moderate NE flow then prevailing through Tue night. $$ Lewitsky