000 AXNT20 KNHC 010431 TWDAT 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 0400 UTC. ...SPECIAL FEATURES... Hurricane Sam is centered near 25.0N 61.2W at 01/0300 UTC or 480 nm SSE of Bermuda moving NNW at 14 kt. Estimated minimum central pressure is 938 mb. Maximum sustained wind speed is 125 kt with gusts to 150 kt. The eye is 30 nm in diameter. Numerous moderate scattered strong convection extends outward from the center 150 nm in the N semicircle and 90 nm S semicircle. Scattered moderate convection is elsewhere within 240 nm N semicircle. Maximum significant wave height near the center is estimated at 43 ft. On the forecast track, the core of Sam will pass to the east of Bermuda early Saturday. Some fluctuations in intensity are expected during the next day or so, but Sam is forecast to remain a major hurricane into Saturday, with additional weakening anticipated later in the weekend. 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 10.6N 30.7W at 01/0300 UTC or 510 nm SW of the Cabo Verde Islands moving WNW at 10 kt. Estimated minimum central pressure is 997 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Numerous moderate scattered strong convection is within 180 nm of the center in the northern semicircle. Scattered moderate convection is within 180 nm SE quadrant. Maximum significant wave height near the center is estimated to be near 18 ft. A west-northwest to northwest motion is expected through the weekend. Gradual strengthening is forecast during the next day or so. However, a weakening trend is expected to begin over the weekend. Please read the latest High Seas Forecasts issued by Meteo-France at website http://weather.gmdss.org/II.html and by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml as well as the latest NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave axis extends along 51W from 05N to 16N, moving W at 15-20 kt. Isolated showers and tstorms are noted along and east of the wave axis from 08N-11N. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the W coast of Mauritania near 18N16W to 12N25W, then resumes W of Victor from 08N34W to 06N39W. The ITCZ extends from 06N39W to 06N49W, then resumes W of a tropical wave from 07N52W to 07N58W. Aside from the convection associated with Victor and the tropical wave, scattered moderate to strong convection is noted from 07N-12N, within 120 nm of the west coast of Africa. Scattered showers are seen from 05N-11N between 37W-48W. GULF OF MEXICO... Ample moisture noted in Total Precipitable Water imagery over the western Gulf is leading to scattered moderate showers and isolated tstorms. However, a mid- to upper-level ridge centered over the SW Gulf of Mexico is acting to suppress the coverage and intensity of these showers and storms. A recent ASCAT pass shows mainly moderate E winds across the basin. Seas are 2-4 ft over the western Gulf and 1-3 ft across the eastern Gulf. For the forecast, a weak ridge of high pressure will persist north of the Gulf through tonight, supporting tranquil conditions. 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 should move across the Gulf on Mon and Tue, but with little enhancement of the winds and seas. CARIBBEAN SEA... An upper level trough extending from the W Atlantic to the SW Caribbean continues to support scattered showers and isolated tstorms between the Isle of Youth and Puerto Rico, including the Cayman Islands, Jamaica and Hispaniola. Showers and tstorms are also noted along the N coast of Venezuela and Colombia. A recent ASCAT pass shows gentle trades across the basin, with moderate winds in the south-central Caribbean. Moderate to locally fresh NE winds are in the Windward Passage. Seas of 2-4 ft prevail over much of the basin, except 1-2 ft in the NW Caribbean. Swell from Hurricane Sam is affecting the NE Caribbean passages from the Mona Passage to the northern Leeward Islands. The swell will begin to gradually subside later today. For the forecast, tranquil trades will continue over the Caribbean through today. As high pressure builds in behind Hurricane Sam, winds are expected to become moderate to fresh across the central and E Caribbean beginning Sat and continuing through mid week. ATLANTIC OCEAN... Refer to the section above for details on Hurricane Sam and T.S. 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. An upper-level trough over the W Atlantic, to the west of Hurricane Sam, is supporting a weak stationary front along 30N between 70W-78W, but this front will be dissipating later today. Scattered showers and isolated tstorms are seen over the central and NW Bahamas and east of Florida. 1031 mb high pressure over the Azores dominates the Atlantic to the east of Sam. ASCAT shows fresh to strong trade winds from 15N-25N between 28W-41W, and from the Madiera and Canary Islands westward to 28W. For the forecast, Hurricane Sam will move to near 30N62W this evening and to near 33N 60.5W Sat morning. Large swell from Sam will impact the area northeast of the Bahamas today through Saturday, then gradually subside Saturday night through Sunday. Seas up to 12 ft will reach as far west as about 72W, and 10 ft seas will make it to 77W, due to swell from Sam. After that time, stronger high pressure will build into the area, which will bring moderate to occasionally fresh winds to the western Atlantic early next week. $$ Hagen