Atlantic Tropical Weather Discussion

000 AXNT20 KNHC 030512 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Fri Oct 2 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 0450 UTC. …SPECIAL FEATURES… Recently upgraded Tropical Storm Gamma is centered near 19.1N 86.1W at 03/0300 UTC or 96 nm SSE of Cozumel, Mexico moving NW at 8 kt. Estimated minimum central pressure is 998 mb. Maximum sustained wind speed is 35 kt with gusts to 40 kt. Numerous moderate to strong convection is within 200 nm in the W semicircle, with some of the convection moving over the Yucatan, Belize, and Honduras. Seas are up to 10 ft. A slower northwestward motion is expected during the next couple of days, followed by a turn to the west or west-southwest. On the forecast track, the center of Gamma should be near the northeastern Yucatan Peninsula on Saturday. Some strengthening is expected before Gamma moves inland over the northeastern Yucatan Peninsula on Saturday. After landfall, slight weakening or little change in strength is expected. Gamma is expected to produce heavy rainfall that could result in life-threatening flash flooding over portions of the Yucatan Peninsula, far western Cuba and well away from the center in the Mexican states of Campeche, Tabasco, and northern Chiapas. Seas will build over the far northwestern Caribbean and Yucatan Channel through Saturday night, and in the south-central Gulf through early next week. Please read the latest NHC Public Advisory at and the Forecast/ Advisory at for more details. …TROPICAL WAVES… An Atlantic Ocean tropical wave is along 40W from 18N southward, moving W at 10-15 kt. A broad area of disorganized area of scattered moderate to isolated strong convection is noted from 08N-18N between 31W-43W. A Caribbean Sea tropical wave is along 69W from 18N southward, moving W at 10 kt. An area of scattered moderate convection is located from 13N-18N between 63W-71W. Locally heavy rainfall and gusty winds are affecting portions of the ABC Islands, the Lesser Antilles, the Virgin Islands, and Puerto Rico. Environmental conditions are expected to become a little more conducive for development, and a tropical depression could form next week while the system moves westward or west-northwestward at about 15 mph across the central and western Caribbean Sea. There is a low chance of tropical cyclone formation with this wave in the next 2 days and a medium chance in the next 5 days. …MONSOON TROUGH/ITCZ… The monsoon trough passes through coastal sections of Senegal near 15N17W to 09N27W. The ITCZ continues from 09N27W to 07N38W, and from 06N42W to the coast of Brazil near 03N51W. Scattered moderate convection is noted along the ITCZ from 03N-09N between 41W-45W. Otherwise, convection near the ITCZ is associated with the tropical wave along 40W. GULF OF MEXICO… At 0300 UTC, a stationary front extends from southwest Florida near 26N81W to 22N90W. Scattered moderate convection is noted within 100 nm south of the front. A stationary front farther north extends off the Tampa Bay, Florida coast near 27N83W to 26N86W. No significant convection is associated with this front. High pressure building across the western and central Gulf is inhibiting any convection. Latest scatterometer data indicated fresh to strong NNE winds across the central Gulf southward into the Bay of Campeche. Moderate N winds are along the Florida Panhandle with gentle easterly winds off the Texas coast. Seas range 3-6 ft with upwards of 10 ft north of the Yucatan and in the south-central Bay of Campeche. Tropical Storm Gamma will move to 19.8N 86.9W Sat morning, inland to 20.8N 87.6W Sat evening, and inland to 21.6N 88.0W Sun morning. Gamma will move into the south-central Gulf to near 22.0N 88.3W Sun evening, 21.9N 88.9W Mon morning, and to 21.7N 90.0W Mon evening. Gamma will change little in intensity as it moves through the far southwest Gulf through Tue. Meanwhile a weak stationary front reaching from SW Florida to north of the Yucatan peninsula will dissipate Sat ahead of Gamma. Another stationary front from central Florida to the central Gulf will dissipate Sun. A cold front will move into the northern Gulf and stall through late Mon. 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. Scattered moderate convection is noted off the coast of Colombia into the SW Caribbean, S of 14N between 72W-77W. Scattered convection is moving across portions of Cuba and Jamaica associated with T.S. Gamma. The latest scatterometer data indicates that fresh to locally strong trade winds are off the coast of Hispaniola and Puerto Rico. Otherwise, light to gentle winds are in the SW Caribbean with moderate to fresh winds in the central and eastern Caribbean. Seas are averaging 3 to 6 ft with upwards of 9 ft near the Mona Passage. Tropical Storm Gamma will move to 19.8N 86.9W Sat morning, inland to 20.8N 87.6W Sat evening, inland to 21.6N 88.0W Sun morning, 22.0N 88.3W Sun evening, then farther into the Gulf of Mexico. Elsewhere, fresh to strong trades are expected over the eastern and central Caribbean through Sun night. Winds and seas will subside Mon and Tue across the basin. ATLANTIC OCEAN… A stationary front extends off the central Florida coast, from 31N78W to Melbourne, Florida near 28N80W. A stationary front farther south extends along the northern Bahamas and the SE Florida coast, from 31N74W to south of Miami near 26N80W. Scattered moderate convection is within 40 nm of the southern stationary front. A pre-frontal trough is analyzed from 26N78W to central Cuba near 23N80W. Scattered moderate convection is noted near this feature from 22N-25N between 77W-80W. A mid-level trough near 64W is giving way to isolated thunderstorms in the west-central Atlantic from 21N-28N between 60W-68W. A surface trough in the central Atlantic is noted along 46W from 24N-30N. Scattered moderate convection is noted near this trough from 27N-33N between 40W-48W. Otherwise, surface ridging is noted across the basin anchored by a 1033 mb high near 41N37W. Light winds are noted in the western Atlantic off the coasts of Florida and the Bahamas. Moderate to fresh easterly winds are noted across the central and eastern Atlantic strong N winds off the coasts of Western Sahara and Mauritania. Seas are averaging 3-6 ft across the western and central Atlantic. A stationary front extending from 31N74W to 26N80W will gradually dissipate Sat. A reinforcing cold front reaching from 31N78W to 29N80W will stall from near 31N79W to central Florida by Sat afternoon, and then retreat northward as a warm front on Sun. Meanwhile, 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 third weak front will move over the Atlantic waters east of NE Florida late Sun and dissipate by early Tue. $$ AReinhart


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