000 AXNT20 KNHC 152338 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sat Oct 16 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... Atlantic Gale Warning: An elongated area of low pressure is located near 27N56W or about 550 nm southeast of Bermuda. A surface trough extends from 27N53W to the low to 21N70W. Recent satellite derived wind data show gale force winds within about 60 nm just south of the low center. A large area of fresh to locally strong winds is also noted over the central Atlantic E of the trough axis, roughly N of 22N between 48W and 62W. The associated shower and thunderstorm activity remains disorganized, with clusters of moderate to isolated strong convection covering the waters mainly N of 23N E of the trough to 41W. This system is beginning to merge with a larger mid-latitude trough. Strong upper-level winds are expected to prevent additional tropical development of this system as it accelerates to the east- northeast over the next several days. Seas of 8 to 13 are expected within the area of gales. The low is forecast to move N of the forecast region late tonight into Sat morning. Gulf of Mexico Gale Warning: A cold front will enter the NW Gulf tonight with fresh to strong northerly winds following it. The front will reach south central Florida to western Bay of Campeche Sun morning with moderate to fresh N to NE winds across most of the Gulf. Gale-force N winds will briefly move across the Mexican waters Sat afternoon through evening and are then expected to develop off of Veracruz early Sun through afternoon. Seas are forecast to build to 8-10 ft with the strongest winds. 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 29W south of 18N, moving W at 10 to 15 kt. Scattered moderate convection is noted from 00N and 10N between 25W and 35W. The axis of a tropical wave is near 44W south of 18N, moving W at around 10 to 15 kt. Scattered moderate convection is seen from 03N and 13N between 40W and 50W. The axis of a tropical wave is near 65W south of 17N, moving W at around 10 to 15 kt. No deep convection is observed near the wave axis. The axis of a tropical wave is near 78W south of 19N, moving W at 10 to 15 kt. Scattered moderate convection is observed over the central Caribbean on either side of the wave axis and mainly N of 13N between 74W and 78W. The axis of a tropical wave is near 89W south of 19N, moving W at 10-15 kt. The wave extends southward into the E Pacific region. Scattered showers are near the northern end of the wave axis over the Yucatan peninsula. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 09N14W to 05N20W. The ITCZ continues from 05N20W to 06N27W to 06N43W to the coast of French Guiana at 05N53W. Aside from convection noted in the tropical waves section above, scattered moderate convection is noted from 00N to 11N between 20W and 53W. GULF OF MEXICO... A weak ridge dominates the Gulf waters anchored by a 1016 mb high pressure located over eastern Georgia. A surface trough remains over the NE Gulf coastline with scattered moderate convection. Light to gentle winds prevails across the Gulf waters based on scatterometer data. Seas are in the 3-4 ft range over the NW Gulf, and 1-3 ft elsewhere. For the forecast, a cold front will enter the NW Gulf tonight with fresh to strong northerly winds and building seas following it. Please, see the Special Features section for more details about the Gale Warning in effect for the SW Gulf waters. CARIBBEAN SEA... A couple of tropical waves are moving westward across the Caribbean Sea. Please, see the Tropical Waves section for details. A weak pressure pattern prevails across the basin due to the presence of lows/troughs N of the Caribbean Sea. Gentle to moderate winds are noted over eastern Caribbean mainly south of 14N. Light to gentle winds prevail elsewhere. Seas are in the 3-4 ft range over the eastern Caribbean and 1-3 ft elsewhere. For the forecast, an upper level trough extending from the Bahamas to the NW Caribbean will support active weather across the central Caribbean and extreme NE Caribbean this weekend. A weak pressure gradient across the Caribbean basin will lead to tranquil marine conditions. A cold front will enter the SW N Atlantic over the weekend and move SE, and bring a return to moderate trade winds to the Caribbean Mon night. ATLANTIC OCEAN... Please refer to the Special Features section above for details on the Gale Warning over the Atlantic waters associated with a low center. Aside from Special Features low, a weakening stationary front extends from 31N30W to 29N40W to 31N50W to a 1007 mb low pressure located N of area near just W of Bermuda near 32N64W. Recent scatterometer data indicate fresh to locally strong S to SW winds south of the front between 45W and 50W. The remainder of the Atlantic forecast waters is under the influence of a ridge with a 1022 mb high pressure located N of the Madeira Islands. A pair of tropical waves are between the W coast of Africa and the Lesser Antilles. Please, see the Tropical Waves section for details. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Low ash concentrations moving NW. 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 W of 65W, the gale low pres will accelerate NE and exit the region late tonight into early Sat morning. Active weather associated with this system will persist across the SE waters through tonight. A cold front will move southeastward off the SE U.S. coast and across Florida by the end of the weekend, reaching from Bermuda to the Florida Keys by Mon morning. Expect fresh to strong N to NE winds behind the front through Mon morning. $$ ERA