000 AXNT20 KNHC 292343 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Tue Sep 29 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 2230 UTC. ...SPECIAL FEATURES... ...GULF OF MEXICO GALE WARNING... A strong cold front moving across the Gulf waters now extends from the Florida Big Bend SW to 20.5N95W then SE across the central Bay of Campeche to 18N93W. Scattered moderate isolated strong convection is along and SE of the front to a line from near Ft Meyers, Florida to the NE part of the Yucatan Peninsula. The front will reach the SE Gulf waters early on Wed and the Straits of Florida by Wed evening. In the wake of the front, strong northerly winds are occurring west of the front and south of 21N, and will continue through around sunrise Wed morning. Seas are forecast to build to 18 ft over the SW Gulf by this evening and then to 20 ft tonight. These conditions will begin to improve by Wed morning. Please see the latest High Seas Forecast at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...TROPICAL WAVES... A tropical wave over the eastern Atlantic is along 19W-20N from 01N-14N. The wave is moving west at about 10-15 kt. Scattered showers are noted in the vicinity of this wave. A tropical wave axis is along 47W from 01N-15N, moving W at 10-15 kt. Scattered moderate isolated strong convection is from 07N-15N between 42W-51W. A tropical wave axis is along 63W from 10N-19N, moving W at 10-15 kt. Scattered moderate convection is behind the wave from 10N-20N between 55W-63W. A tropical wave moving across the central Caribbean is currently located along 74W, moving W at 10 kt. Scattered moderate isolated strong convection is noted from 14.5N to Hispaniola between 67W and 73W. This wave will continue moving westward across the basin through the period accompanied by active weather and enhanced winds. This feature is expected to become part of a broad low- pressure area over the western Caribbean in a few days. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 10N14W to 05N30W. The ITCZ extends from 05N30W to 06N39W. The ITCZ resumes W of a tropical wave near 05N46W to 03N54W. Besides the convection mentioned in the tropical wave section, no significant convection is noted near these boundaries at this time. Gulf of Mexico... Refer to the section above for details on the Gale Warning currently in effect for the SW Gulf. A surface ridge from the Atlantic extends across South Florida into the southeastern Gulf. A surface trough is noted southeast of the cold front from the Yucatan Peninsula to SW Florida, where most of the active convection is focused. Drier air is moving into the far northwest Gulf of Mexico behind the cold front. The most recent scatterometer data depict light to gentle winds over the southeast Gulf, and gentle to moderate southerly winds ahead of the front. Fresh to strong northerly winds follow the front, becoming gale force south of 21N. Looking ahead, the cold front will continue moving SE across the basin overnight with strong to near gale force northerly winds behind it and gale force winds in the region of Veracruz. A secondary frontal boundary will drop southward to the northern Gulf early on Fri and reach the far southwestern Gulf by Fri evening. Strong high pressure will build in behind this front. The pressure gradient between the front and broad low pressure that is expected to form over the western Caribbean by the end of the week is expected to freshen the northeast winds over most of the southeastern Gulf by the end of the week. These winds may reach strong speeds on Sat along with building seas. CARIBBEAN SEA... A tropical wave is moving over the central Caribbean, while another one is approaching the Lesser Antilles. Please refer to the Tropical Waves section above for details. Across the west Caribbean, a 1006 mb low pressure is noted over northern Colombia with the Pacific monsoon trough extending west across Panama and Costa Rica. Scattered moderate convection occurring earlier along the boundary has shifted over land across Colombia and Panama and the adjacent Caribbean waters south of 10N. To the NW, limited convection is noted. Scatterometer data depicts light to moderate trade winds across most of the basin except between 60W- 70W, where moderate to fresh winds prevail. Moderate to fresh trade winds over the central Caribbean will increase to fresh to strong speeds tonight. Moderate winds will continue elsewhere, except for gentle winds over the northwestern Caribbean. A tropical wave, currently located near 74W, will continue moving westward across the basin through the period accompanied by active weather and enhanced winds. ATLANTIC OCEAN... Refer to the section above for details on the tropical waves moving across the tropical Atlantic. Surface ridging prevails across the basin, anchored by a 1031 mb high is centered over the central Atlantic near 39N44W. Weak high pressure over the western Atlantic is maintaining gentle to moderate winds across the area. The high pressure will begin to retreat eastward through Wed in response to a cold front that will reach the southeastern U.S. coast tonight and move over the northwest part of the area through Wed. The front will weaken through the end of the week. Scattered showers and thunderstorms are expected ahead of the cold front. $$ Stripling