000 AXNT20 KNHC 020546 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Sat Oct 2 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 0500 UTC. ...SPECIAL FEATURES... Hurricane Sam is centered near 32.1N 61.1W at 02/0600 UTC or 185 nm E of Bermuda moving NNE at 15 kt. Estimated minimum central pressure is 945 mb. Maximum sustained wind speed is 120 kt with gusts to 145 kt. Numerous moderate to scattered strong convection extends outward from the center 240 nm in the N semicircle and 90 nm in the S semicircle. Scattered moderate convection exists elsewhere within 300 nm in the NE quadrant. Maximum significant wave height near the center is estimated at 40 ft, with 12 ft seas extending outward as much as 315 nm from the center. Sam is expected to turn NE by tonight. Weakening is anticipated over the next couple of days, but Sam should remain a major hurricane into Sunday. Early next week, Sam should begin to transition to a strong extratropical storm. 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 Storm Victor is centered near 12.3N 35.3W at 02/0300 UTC or 700 nm WSW of the Cabo Verde Islands moving WNW at 11 kt. Estimated minimum central pressure is 999 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Scattered moderate to strong convection is occurring in the NE quadrant between 120-420 nm from the center. There is no convection in the other three quadrants. Maximum significant wave height near the center is estimated to be near 20 ft, and the seas should gradually diminish during the next couple days. Victor is forecast to gradually turn NW over the next several days. The tropical storm is forecast to weaken to a remnant low Monday 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 tropical wave axis extends along 56W from 05N to 19N, moving W at 15 kt. Scattered showers and isolated tstorms are within 120 nm either side of the wave axis from 08N-14N. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Guinea near 10N 14.5W to 06N20W. The ITCZ then extends from 06N20W to 07N28W. The ITCZ resumes to the west of Tropical Storm Victor near 07N39W to 07N56W. Aside from convection associated with Victor and the tropical wave described in the sections above, scattered moderate to isolated strong convection extends from 02N-13N east of 19W. Scattered moderate convection is noted within 60 nm either side of a line extending from 01N24W to 04N28W to 11N31W. Similar convection is seen near the ITCZ from 05N-09N between 42W-53W. GULF OF MEXICO... An eastward-moving short-wave digging over the Texas panhandle is inducing upper-level diffluence and rising motion ahead of it over the western Gulf of Mexico. This, coupled with high moisture content noted in Total Precipitable Water imagery, is leading to scattered moderate and isolated strong convection over the west-central and NW Gulf of Mexico from 24N-29N between 94W-98W. The latest ASCAT data show mainly moderate E winds across the basin, except for some fresh winds in the Florida Straits, near the Yucatan Peninsula and in the convection near the Mouth of the Rio Grande River. Seas are 2 to 4 ft across the basin. For the forecast, a weak ridge of high pressure will persist north of the Gulf through early this morning, supporting tranquil conditions across most of the basin. Stronger higher pressure will build across the region by Sun, allowing winds and seas to increase over the SE Gulf over the weekend. A weak cold front will move across the Gulf on Mon and Tue, with little enhancement of the winds or seas. CARIBBEAN SEA... A fairly modest pressure gradient is supporting mainly moderate trades over the basin, with seas of 2 to 4 ft. The latest ASCAT data show some locally fresh trades in the SE and south-central Caribbean. An upper-level trough extending from eastern Cuba to Costa Rica is supporting scattered showers and tstorms covering much of the eastern and central Caribbean Sea, east of 74W. Moisture in this area is also being aided by a tail of moisture that extends southwestward all the way from Hurricane Sam. West pf 74W, additional showers and storms are found near Jamaica, as well as in the SW Caribbean south of 12N, associated with the east Pacific monsoon trough. For the forecast, high pressure will build north of the area this weekend. This will bring an increase in trade winds and seas across the central and E Caribbean starting later today and continuing through the middle of next week. ATLANTIC OCEAN... Refer to the Special Features section above for details on Major Hurricane Sam and Tropical Storm 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. Aside from Hurricane Sam and Tropical Storm Victor, the tropical N Atlantic is dominated by ridging from a high pressure of 1028 mb centered near 37N39W. A ridge axis extends SW from that high pressure to the Virgin Islands. Moderate anticyclonic winds prevail near the ridge axis. Southeast of the ridge axis, fresh NE trades prevail. These winds become strong closer to Tropical Storm Victor. Hurricane Sam is located NW of that ridge axis, a couple hundred nm east of Bermuda. Mostly moderate to fresh NE winds prevail across the western Atlantic, west of 67W and south of 31N. Outside of the two tropical cyclones, seas of 6 to 9 ft prevail across the basin. A line of broken showers and thunderstorms about 60 nm wide extends from 27N56W to 20N63W. Additional showers and tstorms are noted over the waters from just north of Puerto Rico to just north of the Windward Passage. Isolated showers and tstorms are seen in the vicinity of the NW Bahamas. Hurricane Sam is northeast of the forecast area near 32.1N 61.1W and moving NNE near 15 kt. Swell from Hurricane Sam has reached to the Bahamas, and will reach the east coast of Florida and Georgia later today. In the area north of 26N and east of 68W, swell from Sam will be quite significant through today. Swell over the western Atlantic will begin to subside on Sunday as Sam accelerates northeastward over the north Atlantic. High pressure will build into the W Atlantic in the wake of Sam, which will bring moderate to occasionally fresh winds through Tue. $$ Hagen