000 AXNT20 KNHC 160435 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 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 0000 UTC surface analysis and satellite imagery through 0425 UTC. ...SPECIAL FEATURES... Atlantic Gale Warning: A 1004 mb low pressure system is located near 32N49W or between Bermuda and the Azores. A surface trough extends from the low pressure to 22N69W. Latest scatterometer satellite data show gale-force winds in a small area about 270 nm south of the center. A large area of fresh to locally strong winds is also observed over the central Atlantic E of the trough axis, roughly N of 20N between 40W and 60W. Scattered moderate to isolated strong convection is present within 250 nm E of the trough axis, especially between 42W and 60W. This system is expected to move quickly to the NE and merge with a strong mid- latitude system over the N Atlantic. Seas up to 13 ft are expected within the area of gales. The area of gales is expected to lift north of our area this afternoon. Gulf of Mexico Gale Warning: A cold front is approaching the SE Texas coast and will move into the NW Gulf of Mexico over the next few hours 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 up to 15 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 along 31W, south of 19N and moving W at about 15 kt. Scattered moderate convection is noted where the wave interacts with the ITCZ from 02N to 10N and between 25W and 37W. A stable environment N of 10N is suppressing the development of showers and thunderstorms. The axis of a tropical wave is along 46W, south of 19N and moving W at 10-15 kt. Scattered moderate convection is seen where the wave interacts with the ITCZ from 02N to 13N and between 37W and 52W. A stable environment N of 13N is suppressing the development of showers and thunderstorms. The axis of a tropical wave is along 67W, south of 20N and moving W at about 15 kt. No deep convection is observed near the wave axis. The axis of a tropical wave is along 80W, south of 19N and moving W at 10-15 kt. A few showers are present near the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Guinea-Bissau near 12N16W to 07N23W. The ITCZ continues from 07N23W to 04N31W, then west of a tropical wave from 04N32W to 05N45W, and then west of another tropical wave from 06N48W to 09N60W. Aside from the convection mentioned in the Tropical Waves section, no other convection is observed on satellite imagery. GULF OF MEXICO... Refer to the Special Features for information on the Gale Warning. A cold front approaches the NW Gulf of Mexico and is expected to move into the region in the next few hours. A line of showers and thunderstorms is seen over southern Texas and NE Mexico and this activity is likely to move over the offshore waters. Meanwhile, a surface trough over Yucatan extends northward to 24N88W. A couple of showers and isolated thunderstorms that developed over the peninsula in the evening have moved into the E Bay of Campeche, but this activity is expected to quickly wane over the next few hours. The rest of the basin is dominated by a weak 1015 mb high pressure system positioned over the NE Gulf. The weak pressure gradient results in moderate or weaker anticyclonic winds and 1-3 ft seas across the entire Gulf of Mexico. For the forecast, 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 late afternoon. CARIBBEAN SEA... A couple of tropical waves are moving westward across the Caribbean Sea. Please, see the Tropical Waves section for details. Divergence aloft provided by a sharp upper level trough that drapes across the NW Caribbean Sea into Central America results in widely scattered moderate to isolated convection across the NW and central Caribbean. The strongest convection is noted from the coast of N Colombia to 17N and between 72W and 76W. Fairly tranquil weather conditions prevail elsewhere in the basin. Recent scatterometer satellite data show fresh to strong trades in the south-central Caribbean, likely associated with the convection in the area. Moderate or weaker trades are found in the rest of the Caribbean. Seas of 3-4 ft are prevalent E of 75W and 1-2 ft elsewhere. For the forecast, a weak pressure gradient across the Caribbean basin will lead to tranquil marine conditions. A cold front will enter the NW Atlc over the weekend and move SE. High pres building in the wake of the front will 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 north-central tropical Atlantic. Aside from the low pressure producing gale-force winds discussed in the Special Features section, the rest of the tropical Atlantic is dominated by a 1021 mb high pressure located near the Madeira Islands that extends SW to the Lesser Antilles and provides for fairly tranquil weather conditions. A weak surface trough extends from 30N63W SW to 26N72W and NW to 28N78W near the NW Bahamas, but no deep convection is noted with this system. Satellite-derived wind data show fresh trades from 08N to 13N and between 33W and 47W. Another region of fresh to locally strong N-NE winds is found E of 23W and from 15N to 27N, with the strongest winds noted near the coast of Western Sahara. Moderate or weaker winds are present in the rest of the basin. Seas of 4-7 ft prevail W of 60W, while seas of 5-8 ft are noted S of 20N between Africa and the Lesser Antilles. Seas of 4-7 ft are prevalent elsewhere. 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, 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. $$ DELGADO