083 AXNT20 KNHC 031048 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Sun Oct 3 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 0930 UTC. ...SPECIAL FEATURES... Hurricane Sam is centered near 37.3N 55.9W at 03/0900 UTC or 575 nm SSW of Cape Race Newfoundland, moving NE at 15 kt. Estimated minimum central pressure is 960 mb. Maximum sustained wind speed is 90 kt with gusts to 110 kt. Numerous moderate and isolated strong convection extends outward from the center 90 nm. Maximum significant wave height is estimated at 39 ft, with seas 12 ft and greater extending outward as far as 300 nm from the center. A general track to the NE with an increase in forward speed is expected for the next few days. Slow weakening is anticipated during the next few days, and Sam should transition into a powerful post-tropical cyclone on Monday night. Please read the latest High Seas Forecast issued by the Ocean Prediction Center at website https://ocean.weather.gov/mobile/mobile_product.php?id=NFDHSFAT1 and the latest NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Tropical Depression Victor is centered near 16.1N 39.9W at 03/0900 UTC or 915 nm W of the Cabo Verde Islands, moving NW at 14 kt. Estimated minimum central pressure is 1007 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Scattered moderate to strong convection extends outward from the center 360 nm in the NE quadrant. Maximum significant wave height near the center is estimated to be near 14 ft. A general NW motion is expected to continue over the next few days. Gradual weakening is forecast over the next couple of days, and Victor is expected to become a remnant low tonight. The system is then forecast to dissipate by Tuesday night. Please read the latest High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... A new tropical wave along the coast of west Africa is along 20W from 03N-19N, moving W at 10-15 kt. Scattered moderate convection is within 150 nm either side of the wave axis from 12N-18N. An eastern Caribbean tropical wave has its axis along 66W from 16N southward to Venezuela, moving W at 15 kt. Scattered moderate to strong convection is noted with and ahead of the wave from 12.5N to 18.5N between 65W and 73W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Senegal near 13.5N17W to 07N20W. The ITCZ is from 07N20W to 06.5N33W, where there is a break in the ITCZ. The ITCZ resumes from 08N42W to 06N50W to 08.5N60W. Scattered moderate isolated strong convection is noted from 01.5N-12.5N E of 34W to African coast, and within 60 nm along and N of ITCZ between 56W and 61W. GULF OF MEXICO... Mid to upper-level ridging is present over the Gulf of Mexico. While the mid-level ridging is causing some subsidence over the southern Gulf, ample moisture is present over the northern Gulf. Scattered moderate isolated strong convection is noted over the north- central and northeast Gulf of Mexico, north of 25.5N between 85W and 94W. A small cluster of strong tstorms is along the western Bay of Campeche between Tuxpan and Veracruz. Overnight ASCAT data show fresh E winds in the Florida Straits and SE Gulf of Mexico, where seas are 4 to 5 ft. Gentle to moderate E to SE winds are noted elsewhere across the basin, with 2 to 3 ft seas. A weak ridge of high pressure north of the Gulf extends from the western Atlantic westward along 34N, and will move eastward through Tue. This will support tranquil conditions across all but the southeast sections of the basin. A weak cold front will move across the Gulf on Mon and Tue, with little enhancement of the winds and seas. CARIBBEAN SEA... An upper-level trough extends from the NW Bahamas to central Cuba to Nicaragua. Showers and tstorms are being enhanced along and to the east of the upper-level trough axis. Scattered moderate and isolated strong thunderstorms cover the north-central Caribbean, north of 15.5N between 69W-81W. Strong convection is seen in the south-central to SW Caribbean south of 13N between 70W-80W. Overnight ASCAT data show fresh trades in the eastern and central Caribbean, mainly south of 17.5N and east of 77W, where seas are 4 to 6 ft. Moderate trades prevail across most other areas, where seas are 2 to 4 ft. NOAA buoy 42060, located near 16.4N 63.3W has recently reported 19 kt winds and 6 ft seas. Earlier altimeter data from Saturday afternoon showed seas of about 5 feet from 14N- 17N between 67W-69W. High pressure along the mid Atlc coast along 34N will produce fresh tradewinds from the central Caribbean to the tropical N Atlantic today and persist across the Caribbean through Tue. Winds and seas will become fresh to strong across the central Caribbean Mon and Tue as the high pressure moves slowly eastward. Moderate N to NE swell will affect the tropical Atlc waters through Tue. ATLANTIC OCEAN... Refer to the Special Features section above for details on Hurricane Sam and Tropical Depression Victor. The Cumbre Vieja volcano on the island of La Palma in the Canary Islands near 28.6N 17.8W has been erupting since September 19th. High concentration of volcanic ash is found near the volcano. Marine and aviation interests should monitor this ongoing situation by reading the latest Volcanic Ash Advisory issued by Meteo-France at http://vaac.meteo.fr/volcanoes/la-palma/ for details. West of 60W: A north-south oriented upper-level trough axis extends over the west Atlantic along 76W. A surface trough extends from 25N66W to 21N70W. Scattered moderate showers and tstorms cover the area south of 26N between 63W-80W, with more numerous moderate convection near the surface trough from 21N-26N between 63W-69W. Farther north, a 1021 mb high pressure is centered just offshore of Cape Hatteras, North Carolina. Overnight ASCAT data show fresh trade winds south of 27N and west of 72W, including in the Florida Straits. Moderate trade winds are elsewhere south of 31N and west of 65W. Seas are 5 to 8 ft west of 65W, in NE swell from Hurricane Sam. Between 60W-65W, 8-12 ft seas are still occurring north of 27N, but these seas will gradually subside through Tue as Sam pulls farther away. Buoy 41049 near 27.5N 62.9W is reporting 10 ft seas, mostly in N swell. East of 60W: An upper-level low is near 32N43W. The positioning of Hurricane Sam relative to this upper-low is enhancing upper- level divergence in between the two features, leading to an area of numerous moderate and isolated strong thunderstorms north of 26N between 46W-56W. Surface ridging covers the remainder of the eastern subtropical Atlantic, anchored by a 1024 mb high pressure near 36N33W. Fresh winds cover most of the area from 10N-22N between 30W-60W, except winds up to 30 kt are near T.D. Victor. Seas of 7 to 9 ft prevail across this area, except higher near Victor. Winds near the Windward Islands are fresh to strong. ASCAT also showed fresh to locally strong NE winds near the Canary Islands. From 25N-31N between 25W-60W, mainly moderate or weaker wind speeds prevail, but seas are in the 6 to 8 ft range in mixed swell from Sam and Victor. The exception is north of 29N and west of 55W, where larger seas still prevail from swell due to Sam. Swells generated from Hurricane Sam, centered NE of the area, will move through the regional waters west of 65W through Mon, before new northerly swell from Sam spreads south of 30N. High pressure along the mid Atlc coast will drift slowly eastward through mid week. This will produce moderate to fresh trade winds south of 23N and east of the Bahamas through Tue before spreading into the southeast Bahamas. Active weather is expected to develop across the waters E of 75W and NE the Bahamas Mon night through Tue as a surface trough develops and drifts NW. $$ Stripling