000 AXNT20 KNHC 050533 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Sun Oct 4 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 0000 UTC surface analysis and satellite imagery through 0500 UTC. ...SPECIAL FEATURES... Tropical Storm Gamma has stalled north of the Yucatan Peninsula and is centered near 22.8N 87.2W at 04/0300 UTC or 165 nm N of Progreso, Mexico and 140 nm N of Cozumel, Mexico. Estimated minimum central pressure is 998 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Numerous strong convection is noted within 230 nm of the N semicircle, with scattered moderate convection farther NE of the center from 24N-29N between 82W-85W which is right off the coast of Florida. Seas have built to 18 ft near and to the NW of the center of Gamma, in the south- central Gulf of Mexico, enhanced by a long fetch of persistent NE winds. The 12 ft seas extend 120 nm in the NE quadrant, 45 nm in the SE quadrant, 120 nm in the SW quadrant, and 150 nm in the NW quadrant. Seas are expected to decrease to 13 ft over the next few days. Gamma is forecast to gradually turn toward the southwest or west-southwest on Monday and move slowly in that direction through mid-week. On the forecast track, the center of Gamma will continue to meander offshore of the northern Yucatan Peninsula tonight and pass near or just offshore of the northern coast of the Yucatan Peninsula on Monday and Tuesday. Gradual weakening is anticipated to begin on Monday and continue into Tuesday. Afterward, little change in strength is forecast. Gamma is expected to produce heavy rainfall for several days over portions of southeastern Mexico, the Yucatan Peninsula, Central America, and far western Cuba. This rainfall could result in life-threatening flash flooding and mudslides, particularly in the mountainous regions of southeastern Mexico and Central America. 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. Newly formed Tropical Depression Twenty-Six is centered near 17.0N 77.3W at 05/0300 UTC, or about 65 nm SSW of Kingston, Jamaica and 260 nm ESE of Grand Cayman. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Numerous moderate to isolated strong convection is located within 200 nm in the S semicircle. The depression should continue moving WNW for the next day or so. A faster northwestward motion is expected on Tuesday and Wednesday. On the forecast track, the center of the depression is expected to pass just south of Jamaica through early Monday, move near or over the Cayman Islands Monday night, and approach the Isle of Youth and western Cuba Tuesday afternoon or evening. The system is forecast to move into the southeastern Gulf of Mexico Tuesday night or early Wednesday. Strengthening is expected during the next few days and the system is forecast to be a tropical storm when it nears the Cayman Islands on Monday, and a hurricane when it moves near or over western Cuba on Tuesday. Seas are expected to build to 13 ft over the next few days. Please read the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT1.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMAT1.shtml for more details. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 49W from 20N southward, moving W at 10-15 kt. Scattered moderate convection is well to the east of this wave from 08N-22N between 43W-49W. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through coastal sections of Senegal near 15N17W to 06N36W. The ITCZ continues from 06N36W to 08N48W, then from 07N51W to the coast of Guyana near 06N55W. Scattered showers and isolated thunderstorms are noted along the monsoon trough and ITCZ from 05N-15N between 17W-42W. GULF OF MEXICO... Please see the Special Features section above for information on T.S. Gamma. High pressure ridging continues to extend across the western Gulf with T.S. Gamma moving into the central Gulf. Strong N winds encompass the bulk of the central Gulf of Mexico with moderate to fresh N winds along the NE basin and light to gentle E winds along the Texas coast. Fresh to locally strong N winds are also noted in the SW Bay of Campeche. Away from the direct influence of T.S. Gamma, seas average 3 to 6 ft. Tropical Storm Gamma will move to 22.7N 87.7W Mon morning, 22.3N 88.5W Mon evening, 21.8N 89.5W Tue morning, 21.3N 90.3W Tue evening, 20.3N 90.7W Wed morning, and move inland and weaken to a tropical depression near 20.2N 90.1W Wed evening. Gamma will change little in intensity as it moves slowly over the northwestern Yucatan Peninsula and adjacent waters through late Thu. Tropical Depression will strengthen to a tropical storm near 17.4N 78.3W Mon morning, move to 18.3N 79.8W Mon evening, 20.0N 81.9W Tue morning, strengthen to a hurricane near 22.2N 84.4W Tue evening as it moves across western Cuba and into the southeast Gulf. The hurricane will move to 24.1N 87.0W Wed morning, and 25.4N 88.8W Wed evening. Twenty-Six will change little in intensity as it moves into the north central Gulf by late Thu. CARIBBEAN SEA... Please see Special Features section for information on Tropical Depression Twenty-Six. The monsoon trough extends across the southwest Caribbean from 11N80W to the coast of Costa Rica near 10N83W. Scattered moderate convection is noted across the SW Caribbean, particularly off the coast of Nicaragua, from 09N-15N between 79W-83W. Scattered moderate convection is noted from SW Puerto Rico to Hispaniola in addition to the central Lesser Antilles islands. Numerous strong convection is N of Colombia into the Gulf of Venezuela from 11N-15N between 71W-74W. Fresh to strong SSE winds are noted off the SW coast of Cuba. Moderate to fresh SE winds across the central Caribbean and WNW off the coast of NE Honduras. Gentle to moderate trades are noted in the eastern Caribbean and light to gentle trades are noted in the western Caribbean. Seas average 3-6 ft with upwards of 9 ft off the SW Hispaniola coast. T.D. Twenty-six will become better organized by Mon, reaching near 18.0N 79.1W Mon afternoon as a Tropical Storm, then move more NW and reach near 21.0N 82.8W Tue afternoon just below hurricane strength. TWENTY-SIX is then expected to move NW across western Cuba Tue evening and exit into the SE Gulf of Mexico as a hurricane early Wed morning before continuing off the NW and towards the N central Gulf. ATLANTIC OCEAN... At 05/0300 UTC, a cold front extends near the coast of Florida from 31N76W to 29N79W then stalls near Cape Canaveral, Florida at 28N81W. Showers are noted within 50 nm of the front. Moderate NE winds are north of the front with light to gentle SSE winds ahead of it. A surface trough is located in the central Atlantic from 31N52W to 25N53W. No significant convection is noted with this feature at this time. Moderate to fresh winds are near this trough. This system is expected to move west-southwestward into a region of strong upper-level winds and development is not expected. Otherwise, a broad surface ridge extends from a 1030 mb high west of the Azores across the basin. Gentle to moderate winds are noted across the basin with fresh to locally strong winds north of Cuba. Seas average 3 to 6 ft with upwards of 7 ft east of the Bahamas and 9 ft near the surface trough. In the eastern Atlantic, fresh to locally strong NE winds and seas to 9 ft are active off the African coast of Western Sahara and Mauritania. The front off the coast of Florida will dissipate through early Mon. Elsewhere, the Bermuda High north of our area will support moderate to fresh trades south of 22N, occasionally pulsing to strong north of Hispaniola. A third weak front will move over the Atlantic waters east of NE Florida by early Mon, drift south through Tue then stall from 31N73W to near W Palm Beach Florida by mid week. $$ AReinhart