000 AXNT20 KNHC 032237 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sat Oct 3 2020 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 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1800 UTC surface analysis and satellite imagery through 2200 UTC. ...SPECIAL FEATURES... Tropical Storm Gamma is centered near 20.7N 87.7W at 03/2100 UTC or 30 nm NNW of Tulum Mexico moving NW at 7 kt. Estimated minimum central pressure is 985 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Numerous strong convection is within 180 nm of the center. Scattered moderate to isolated convection is elsewhere over the NW Caribbean, Yucatan Channel, SE Gulf of Mexico, and Yucatan Peninsula, from 17N-25N between 80W- 91W. Given the size and relatively slow movement of Gamma across the northeastern portion of the Yucatan peninsula through tonight, the main threat continues to be heavy rainfall that could result in life- threatening flash flooding over portions of the Yucatan Peninsula and far western Cuba. Please monitor local weather advisories for more details. For marine interests, strong winds and seas at least as high as 16 ft will impact the Yucatan Channel through tonight. In the south- central Gulf, a long fetch of persistent near-gale force NE winds is already causing seas to 12 ft off the north coast of Yucatan, along with rough surf conditions. Adverse marine conditions will persist into mid week in the south-central Gulf due to the expected track of Gamma. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT5.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMAT5.shtml for more details. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 43W from 20N southward, moving W at 10 kt. Low pressure of 1010 mb has formed in association with this wave near 11N43W. A broad area of scattered moderate to isolated strong convection is from 05N-20N between 34W-47W. As this low and wave move WNW or NW over the next couple of days, there is a low chance of tropical formation before they encounter strong upper level winds early next week. A Caribbean Sea tropical wave is along 73W from 18N southward, moving W at 10 kt. Numerous moderate to scattered strong convection is over the central Caribbean from 11N-16N between 66W- 74W. With convection increasing today and environmental conditions expected to become more conducive for development, a tropical depression could form next week while the system moves W or WNW across the central and western Caribbean Sea and then into the southern Gulf of Mexico. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through coastal sections of Senegal near 14N17W to 07N28W. The ITCZ continues from 07N28W to 11N39W, and from 09N44W to the coast of Brazil near 04N52W. Convection near the ITCZ is associated with the tropical wave along 42W, described above. GULF OF MEXICO... Please see the Special Features section above for information on T.S. Gamma that is forecast to move into the southern Gulf of Mexico tonight. Also, see the tropical waves section above for information on a tropical wave that may impact the Gulf toward the middle of next week. A stationary front is located from Naples Florida to 23N87. Another stationary front that had been located in the far eastern Gulf north of the main front has dissipated. Scattered moderate convection is noted within 120 nm on either side of the main stationary front. Seas are from 8-12 ft over a broad area of the south-central Gulf, north of the Yucatan Peninsula, with 4 to 7 ft see else over much of the southwest, central, and southeast Gulf. Strong NE winds are ongoing over the areas with 8 to 12 ft seas. For the forecast, Tropical Storm Gamma near 20.7N 87.7W 985 mb at 5 PM EDT moving NW at 7 kt. Maximum sustained winds 55 kt gusts 65 kt. Gamma will move inland to 21.3N 88.0W Sun morning, 22.0N 88.2W Sun afternoon, 22.1N 88.4W Mon morning, 22.0N 89.1W Mon afternoon, 21.6N 90.4W Tue morning, and 21.0N 91.5W Tue afternoon. Gamma will change little in intensity as it moves near 20.0N 92.0W Wed afternoon. A stationary front from SW Florida near 26N81W to the SE Gulf near 23N86W will dissipate late Sun into Mon. Otherwise, a cold front will move into the northern Gulf Mon and stall over the central Gulf through mid week. CARIBBEAN SEA... Please see the Special Features section on information regarding T.S. Gamma over the Yucatan Peninsula and the tropical waves section regarding the tropical wave in the central Caribbean. Showers and thunderstorms are noted over Puerto Rico, the Leeward Islands, and the Windward Islands. Fresh E winds are occurring over much of the central and eastern Caribbean, with seas of 5 to 7 ft. Light to gentle breezes and modest seas are noted over the southwest Caribbean. For the forecast, Tropical Storm Gamma near 20.7N 87.7W 985 mb at 5 PM EDT moving NW at 7 kt. Maximum sustained winds 55 kt gusts 65 kt. Gamma will move inland to 21.3N 88.0W Sun morning, 22.0N 88.2W Sun afternoon, 22.1N 88.4W Mon morning, 22.0N 89.1W Mon afternoon, 21.6N 90.4W Tue morning, and 21.0N 91.5W Tue afternoon. Gamma will change little in intensity as it moves near 20.0N 92.0W Wed afternoon. Winds and seas over the northwest Caribbean and Yucatan Channel will diminish early next week as Gamma continues to move WNW. Elsewhere, fresh to strong trades are expected over the eastern and central Caribbean through Sun night. Winds and seas will subside through mid week across the basin. ATLANTIC OCEAN... A stationary front, with scattered moderate convection within 60 nm either side of its boundary, extends from 31N73W to 27N80W. Another stationary front is analyzed farther north, from 31N79W to Daytona Beach Florida. No significant weather is associated with that front. A surface trough well ESE of Bermuda, from around 31N46W to 24N50W is producing a large area of disorganized, scattered convection from 28N-31N between 42W-49W. This system is expected to move WSW at 10 kt and some slow development is possible over the next couple of days before it encounters strong upper-level winds. A tight pressure gradient between and expansive high pressure ridge over the western Atlantic and lower pressure over the Caribbean is supporting strong E winds off the north coast of Hispaniola. In the eastern Atlantic, Fresh to strong NE winds and seas to 9 ft are active off the African coast of Mauritania. Elsewhere, generally moderate trade winds persist across the Atlantic with mostly 5 to 7 ft seas. For the forecast for waters west of 65W, the stationary front off the coast of Florida will dissipate by Sun. Otherwise, the Bermuda High north of our area and lower pressure in NW Caribbean associated with T.S. Gamma will support moderate to fresh trades south of 22N, occasionally pulsing to strong north of Hispaniola during the overnight hours through Sun night. Looking ahead, a weak cold front will move over the Atlantic waters east of NE Florida late Sun or early Mon, drift south through Tue then stall from 31N73W to near W Palm Beach Florida by mid week. $$ KONARIK