000 AXNT20 KNHC 031759 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...SPECIAL FEATURES... Tropical Storm Gamma is centered near 20.0N 87.3W at 03/1500 UTC or 17 nm SE of Tulum Mexico moving NW at 8 kt. Estimated minimum central pressure is 983 mb. Maximum sustained wind speed is 60 kt with gusts to 75 kt. Numerous strong convection is within 120 nm of the center. Scattered moderate to strong 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, far western Cuba. Please monitor local weather advisories for more details. For marine interests, strong winds and seas at least as high as 13 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 42W from 20N southward, moving W at 10-15 kt. A broad area of scattered moderate to isolated strong convection is from 05N-20N between 34W-47W. A Caribbean Sea tropical wave is along 71W from 18N southward, moving W at 10 kt. Scattered moderate to strong convection is over the central Caribbean from 11N-16N between 66W-74W. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through coastal sections of Senegal near 14N17W to 09N21W to 07N29W. The ITCZ continues from 07N29W to 11N39W, and from 08N44W to the coast of Brazil near 04N51W. Convection near the ITCZ is associated with the tropical wave along 42W, described above. GULF OF MEXICO... At 1500 UTC, a stationary front extends from southwest Florida near 27N80W to 24N87W. Another stationary front farther north extends from Daytona Beach Florida to Tampa Bay Florida. A recent altimeter satellite pass indicated seas were reaching 12 ft off the Yucatan coast. Moderate NE winds and 3 to 5 ft seas persist elsewhere over the northern Gulf. Seas over the southern Bay of Campeche are likely up to 9 ft, in a combination of mixed NW and NE swell. For the forecast, Gamma will move inland over the Yucatan Peninsula to 20.8N 87.8W this evening, 21.8N 88.1W Sun morning, 22.2N 88.3W Sun evening, 22.3N 88.8W Mon morning, 22.1N 89.7W Mon evening, and 22.0N 91.0W Tue morning. Gamma will change little in intensity as it moves near 21.0N 92.5W early Wed. 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 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. Elsewhere, isolated moderate convection is over the far SW Caribbean and Panama. Strong E winds are noted off the southern coast of Haiti as well, with seas likely reaching 8 ft. Moderate to fresh trade winds and 5 to 7 ft seas are noted elsewhere east of 75W, and north of 18N particularly between Jamaica and eastern Cuba. Light to gentle breezes and modest seas are noted over the southwest Caribbean. For the forecast, Gamma will move inland to 20.8N 87.8W this evening, 21.8N 88.1W Sun morning, 22.2N 88.3W Sun evening, 22.3N 88.8W Mon morning, 22.1N 89.7W Mon evening, and 22.0N 91.0W Tue morning. Gamma will change little in intensity as it moves near 21.0N 92.5W early Wed. Winds and seas over the northwest Caribbean and Yucatan Channel will diminish early next week as Gamma continues to move west. 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 extends from 31N73W to 27N80W. Isolated moderate convection is within 60 nm of the front. Scattered moderate convection is also over the N Bahamas. Another stationary front is analyzed farther north, from 31N79W to Daytona Beach Florida. No significant weather is associated with that front. A surface trough is over the central Atlantic from 31N46W to 24N50W. Scattered moderate convection is from 28N-31N between 42W-49W. The gradient on the southwest side of a ridge is supporting fresh to 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 extending from 31N73W to 27N80W will gradually dissipate late today or tonight. The other stationary front extending from 31N79W to Dayton Beach will dissipate through late Sun. Meanwhile, the high pressure north of our area 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 third weak 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. $$ Formosa