000 AXNT20 KNHC 212317 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Fri Oct 22 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. ...TROPICAL WAVES... The axis of a tropical wave is along 41W, south of 17N and it is moving W at 10-15 kt. Saharan dry air follows the wave axis, as a result convection is limited near the wave. A tropical wave is along 55W, south of 17N. Scattered moderate to isolated strong convection is noted ahead of the wave axis S of 10N between 55W and 60W. This convective activity is also affecting parts of Guyana and Suriname. Another tropical wave is over the eastern Caribbean along 66W, south of 21N and it is moving W at 10-15 kt. This wave is at the leading edge of a large area of Saharan dry air. Scattered showers are near the northern end of the wave axis. The wave is also helping to induce some convective activity over northern Venezuela. A second tropical wave is moving westward across the central Caribbean. Its axis is along 74W extending from the Haiti to N Colombia, and it is moving W at 10-15 kt. Scattered moderate to isolated strong convection is seen over parts of Hispaniola and northern Colombia. ...MONSOON TROUGH/ITCZ... The monsoon trough extends across the coast of Senegal from 14N17W to 10N22W to 03N24W. The ITCZ continues from 03N24W to 01N35W to 01N50W. Aside from convection noted in the tropical waves section above, scattered moderate convection is noted from 05N to 10N and E of 16W to the W coast of Africa, and near 07N20W. GULF OF MEXICO... High pressure of 1025 mb located just E of Bermuda extends a ridge across Florida into the eastern Gulf of Mexico. A surface trough is over the NE Gulf while another surface trough is analyzed over the Bay of Campeche where some shower activity is noted. An area of showers, with embedded thunderstorms is over the SE Gulf and the Straits of Florida where moderate to fresh easterly winds prevail. Mainly gentle to moderate winds dominate the Gulf region with seas in the 3-5 ft range E of 92W, and 1-3 ft elsewhere. Highest seas of 4-6 ft are in the Straits of Florida. For the forecast, weak high pressure will generally dominate the Gulf waters into early next week, although a stalling cold front will skirt across the NE Gulf this weekend. Moderate to fresh easterly winds are expected across the SE Gulf through tonight, otherwise gentle to moderate winds will prevail. CARIBBEAN SEA... A pair of tropical waves are moving westward across the east and central Caribbean. Please, the Tropical Waves section for details. Convection has flare-up over the central and western Caribbean, including Cuba, Hispaniola, Jamaica, NE Honduras, northern Nicaragua and the northern Yucatan Peninsula. A diffluent pattern aloft is helping to induce this convective activity. A surface trough is over the Yucatan peninsula. Latest scatterometer data provided observations of fresh to strong winds E of the Lesser Antilles. Seas are in the 7 to 10 ft range W of 50W based on altimeter data and buoy 41040. Gentle to moderate trade winds are generally observed across the Caribbean Sea, with seas of 3-5 ft S 0f 18N E of 80W, and 1-3 ft elsewhere, except 3-4 ft in the Yucatan Channel. For the forecast, high pressure N of the area will support fresh to locally strong trades E of the Windward Islands through the weekend. During this period, moderate to fresh winds are expected over the south-central Caribbean, with winds reaching locally strong in the Venezuela basin. Gentle to moderate tradewinds will prevail elsewhere. ATLANTIC OCEAN... High pressure of 1025 mb located just E of Bermuda dominates the SW N Atlantic, the Bahamas and Florida. This system extends westward into the eastern Gulf of Mexico. A dissipating frontal boundary stretches from 31N44W to 26N56W, then continues as a surface trough to the Turks and Caicos Islands. Some shower and thunderstorm activity is near the trough axis. Moderate to locally fresh NE winds are N of the trough, particularly between 60W and 70W with seas of 6-7 ft. A 1029 mb Azores High dominates the remainder of the Atlantic forecast area, and is driving moderate to fresh NE to E trades N of the ITCZ. Seas are generally 4 to 6 ft, except 6-9 ft W of the Canary Islands in NW swell. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Ash emission is on-going. A volcanic ash plume is identifiable on satellite imagery moving toward El Hierro Island. 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, high pressure will move east of the forecast region tonight, and a weak cold front will move off the SE U.S. coast Fri night, then stall over northwest portions of the area through the weekend. Moderate to locally fresh winds tonight will subside by Fri as the high pressure moves away from the area. $$ GR