000 AXNT20 KNHC 012332 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Thu Oct 1 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 2300 UTC. ...SPECIAL FEATURES... A well-defined tropical wave along 83W, from 20N southward is moving west at 10-15 kt. Scattered moderate to isolated strong convection is noted from 13N-22N between 76W-84W, including over the Cayman Islands, central Cuba and over portions of Central America. A broad area of low pressure is expected to form in a few days over the NW Caribbean Sea or the extreme southern Gulf of Mexico. There is potential for a tropical depression to develop by early next week, but only if the system remains over water. Regardless of development, this system is expected to produce locally heavy rains, with possible flash flooding, over portions of southeast Mexico, Central America and western Cuba during the next several days, and interests in those areas should monitor the progress of this disturbance. The chance of tropical cyclone formation during the next 48 hours is medium, with a high chance during the next 5 days. ...TROPICAL WAVES... An Atlantic Ocean tropical wave axis is along 33W from 16N southward, moving W at 10-15 kt. Scattered moderate isolated strong convection is within 480 nm E of the wave axis. An eastern Caribbean Sea tropical wave is along 63W from 19N southward, moving W at 15-20 kt. Scattered moderate to isolated strong convection is within 210 nm either side of the wave axis, covering much of the eastern Caribbean Sea east of 68W from Venezuela to the Virgin Islands. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coast of West Africa from 12N16W to 11N20W. The ITCZ continues from 11N20W to 1130W, then resumes west of a tropical wave from 08N36W to 07N45W to 10N59W. Scattered moderate and isolated strong convection is along and within 180 nm N of the ITCZ between 46W-59W. Isolated moderate convection is elsewhere near the ITCZ. Scattered moderate convection is south of the monsoon trough along the coast of Africa from 08N-12N, east of 17W. Other areas of convection are described above in the Tropical Waves section. GULF OF MEXICO... A stationary front extends from southern Florida near 25N81W to the Yucatan Peninsula near 21N89W, then farther to the southwest to 18N92W. Scattered moderate tstorms are along and within 120 nm NW of the front, including over South Florida, western Cuba and the Yucatan Peninsula. Earlier scatterometer passes indicated northerly winds are 20 to 25 kt over the south-central Gulf of Mexico and eastern Bay of Campeche, within 180 nm north of the front. Seas are estimated to be 5 to 8 ft over the southwest Gulf. Farther north, 1022 mb high pressure is centered over the western Gulf near 26N96W. Gentle to moderate NE winds are noted across much of the northern and western sections of the Gulf, with 2 to 4 ft seas. No other shower or thunderstorm activity is observed. For the forecast, the stationary front will slowly dissipate by early Friday morning. A reinforcing cold front will move through the NE Gulf Fri, eventually stalling and dissipating across S Florida and the SE Gulf by late Sat. Meanwhile, a well-defined tropical wave located over the W Caribbean Sea is expected to develop into a tropical depression by early next week, but only if the system moves and remains over the waters of the NW Caribbean Sea or S Gulf of Mexico. This will likely support strong to near gale-force winds and building seas over the south- central and SW Gulf from late Fri to early next week. Scattered to numerous showers and tstorms are likely over the southern Gulf of Mexico during the next several days. CARIBBEAN SEA... Fresh trade winds and 5 to 7 ft seas are evident over much of the central Caribbean between the high pressure over the Atlantic and lower pressure related to the tropical wave in the western Caribbean described in the section above. Scattered to numerous convection covers the western Caribbean west of 75W associated with the well-defined tropical wave, described above in the special features section. The eastern Caribbean tropical wave is quite active with convection as well, described above in the tropical waves section. If the tropical wave over the western Caribbean develops into a tropical cyclone, then SE to S winds over the NW Caribbean could reach strong to near-gale between Fri night and Sat night. This pattern will also support fresh to strong trades over the eastern and central Caribbean between the low pressure and the Bermuda High over the central Atlantic through Sun night. ATLANTIC OCEAN... Scattered moderate to isolated strong thunderstorms are along a stationary front reaching from 32N74W to near Miami Florida. Additional scattered strong convection is near the north coast of central Cuba. An upper trough is supporting a cluster of thunderstorms farther east from 27N-29N between 56W-62W. A weak surface trough from 32N42W to 26N37W is supporting scattered showers near it. The remainder of the subtropical eastern and central Atlantic is dominated by a surface ridge, anchored by a 1036 mb high near 41N37W. An area of fresh to locally strong trade winds and 8 to 9 ft seas is just east of the Leeward and Windward Islands associated with the tropical wave in the eastern Caribbean. Elsewhere, moderate to occasionally fresh trade winds and 5 to 7 ft seas characterize the tropical and subtropical North Atlantic. For the forecast, the stationary front extending from 32N74W to SE Florida will gradually dissipate by Fri. A reinforcing cold front will move into the waters off NE Florida late Fri, before stalling from near 31N79W to central Florida by Sat afternoon, and then retreating northward as a warm front on Sun. Meanwhile, the Bermuda High north of our area and lower pressure in the NW Caribbean will support moderate to fresh trades south of 20N and west of 65W, 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 on Mon and dissipate by early Tue. $$ Hagen