000 AXNT20 KNHC 040539 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 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 0000 UTC surface analysis and satellite imagery through 0520 UTC. ...SPECIAL FEATURES... Tropical Storm Gamma is centered near 21.3N 88.0W at 03/0300 UTC or 74 nm NNW of Tulum, Mexico moving NW at 6 kt. Estimated central pressure is 990 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Numerous strong convection is within 170 nm in the NW quadrant. Scattered moderate to isolated strong convection is also noted in the Yucatan Channel and south of Cuba, N of 18N between 80W-87W. Seas up to 14 ft are along the N Yucatan coast. Gamma is expected to turn toward the north- northwest with decreasing forward speed is expected on Sunday, followed by a turn to the west or west-southwest Sunday night or Monday. On the forecast track, the center of Gamma will move offshore of the Yucatan Peninsula and over the southern Gulf of Mexico on Sunday, and pass near or north of the northern coast of the Yucatan Peninsula Monday and Tuesday. Little change in strength is forecast during the next few days. 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. A tropical wave with an axis along 73W southward from 18N moving W at 10 kt is producing scattered moderate convection from 11N- 16N between 71W-76W. Environmental conditions are expected to become more conducive for development, and a tropical depression is likely to form during the early or middle portions of next week while the system moves westward or west-northwestward at about 15 mph across the central and western Caribbean Sea and then into the southern Gulf of Mexico. Locally heavy rainfall and gusty winds will be possible across portions of Hispaniola, Jamaica, Cuba, and the Cayman Islands during the next few days, and interests on those islands should monitor the progress of this disturbance. This system has a medium chance of development through the next 48 hours and a high chance of formation through the next 5 days. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 44W from 19N southward, moving W at 10 kt. A 1010 mb low is along the wave near 12N44W. Scattered moderate convection is noted from 12N-19N between 40W- 45W. Some slow development of this system is possible during the next couple of days while it moves west-northwestward or northwestward at 10 to 15 kt. Significant development is not expected beyond that time due to the system moving into a region of strong upper-level winds. This system has a low chance of development over the next 48 hours and the next 5 days. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through coastal sections of Senegal near 15N17W to 06N33W. The ITCZ continues from 06N33W to 09N43W and from 09N44W to the coast of French Guiana near 04N52W. Scattered moderate convection is south of the monsoon trough from 02N-09N between 10W-26W. Some scattered moderate convection is moving off the coast of southern Senegal and Guinea-Bissau. Scattered moderate convection is also along the ITCZ from 03N-08N between 33W-38W. GULF OF MEXICO... Please see the Special Features section above for information on T.S. Gamma. At 04/0300 UTC, a stationary front continues to linger off the SW Florida coast near 26N81W to 24N85W. Scattered moderate convection is within 80 nm of the front. High pressure over the western and central Gulf is inhibiting any convection from occurring over those areas. Moderate to strong N to NW winds span across the eastern and central Gulf, cluding the eastern half of the Bay of Campeche. Gentle easterly winds are off the coasts of Texas through Alabama. Seas are from 3-6 ft across the northern and western Gulf with 9-14 ft across the south- central Gulf near T.S. Gamma. Tropical Storm Gamma will move to 21.8N 88.2W Sun morning, 22.2N 88.5W Sun evening, 22.1N 88.9W Mon morning, 21.8N 89.9W Mon evening, 21.3N 90.9W Tue morning, and 20.7N 91.7W Tue evening. Gamma will change little in intensity as it moves southwestward through the eastern Bay of Campeche. A stationary front from SW Florida near 26N81W to the SE Gulf near 23N86W will dissipate late Sun into Mon, ahead of low pressure expected to move from the northern Caribbean across western Cuba into the southeast Gulf Tue. A cold front will move into the northern Gulf Mon, then stall and dissipate over the central Gulf through mid week as the low pressure moves northward. CARIBBEAN SEA... Please see the Special Features section on information regarding T.S. Gamma and the tropical wave in the central Caribbean. The monsoon trough extends across the southwest Caribbean from 13N74W to the coast of Costa Rica near 11N83W. Scattered moderate convection is noted from 10N-14N between 74W-79W. Isolated thunderstorms continue to impact the Lesser Antilles westward into Puerto Rico. Thunderstorms are also noted in the Gulf of Honduras. Gentle to moderate trade winds prevail across most of the Caribbean with fresh winds near the Greater Antilles and light winds in the SW Caribbean. Seas are from 3-6 ft across most of the basin with upwards of 8 ft near the low along the tropical wave. Tropical Storm Gamma will continue to move NW into the south- central Gulf, allowing winds and seas over the Yucatan Channel to diminish through Sun. Meanwhile, another area of low pressure is developing along a tropical wave south of Hispaniola. There is a medium chance this low may form into a tropical depression or tropical storm through late Mon as the low moves through the NW Caribbean. ATLANTIC OCEAN... At 04/0300 UTC, a stationary front is draped off the Florida coast from 31N79W to the coast near Melbourne, Florida at 29N80W. No significant convection is associated with this front but fresh to strong NE winds are north of this front off the NE Florida coast. The stationary front farther south extends from 31N74W to near West Palm Beach, Florida at 27N80W. Scattered showers are within 50 nm of this front. Fresh easterly winds are noted N from Hispaniola to Cuba. A surface trough in the central Atlantic extends from 30N46W to 24N51W. Scattered moderate convection is noted near this feature from 27N-32N between 43W-51W. Moderate to fresh winds are near this trough. This system is expected to move toward the west- southwest at around 10 kt, and some slow development is possible during the next couple of days before it too encounters strong upper-level winds. This system has a low chance of development through the next 48 hours and the next 5 days. Ridging extends across the rest of the basin anchored by a 1033 mb high west of the Azores. Gentle to moderate winds prevail across the basin. The southern stationary front will gradually dissipate through early Sun. The northern stationary front will dissipate through late Sun. Otherwise, the Bermuda High 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. $$ AReinhart