000 AXNT20 KNHC 201209 AAA TWDAT Tropical Weather Discussion...UPDATED NWS National Hurricane Center Miami FL 1205 UTC Sat Aug 20 2022 Updated to include information from the 1200 UTC Intermediate Advisory for Potential Tropical Cyclone Four 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 0945 UTC. ...SPECIAL FEATURES... Potential Tropical Cyclone Four is centered near 23.2N 96.0W at 20/1200 UTC or 170 nm SSE of mouth of The Rio Grande moving NW at 12 kt. Estimated minimum central pressure is 1010 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt, and seas are peaking at 7 to 10 ft north of the center. Scattered moderate convection is noted from 21N-23N between 93W-98W. On the forecast track, the disturbance is expected to reach the coast of northeastern Mexico late this afternoon and then move across the Rio Grande Valley tonight and Sunday. The disturbance is expected to produce total rainfall amounts of 1 to 3 inches, with isolated totals of 5 inches, along the eastern coast of Mexico from the northern portions of the state of Veracruz across the state of Tamaulipas to Nuevo Leon through today. Rainfall of 1 to 3 inches will be possible in South Texas through Sunday morning, with continuing uncertainty in how far north and west these amounts will be realized. The potential exists for flash flooding elsewhere along the track of the disturbance. Swells generated by this system are forecast to affect eastern Mexico and southern Texas this weekend. These swells are likely to cause life- threatening surf and rip current conditions. The disturbance could still strengthen slightly and become a tropical storm later today before reaching the coast of northeastern Mexico. Please consult products from your local weather office. Please, read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Potential Tropical Cyclone Four NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... An eastern Atlantic tropical wave is near 32W from northwest of the Cabo Verde Islands at 19N southward, and moving west at 10 to 15 kt. Scattered moderate convection is noted from 05N to 12N between 30W and 40W. An eastern Caribbean tropical wave is near 68W from 21N southward, moving west at 20 to 25 kt. Scattered moderate convection is occurring over Venezuela, while scattered showers are noted over the Mona Passage and adjacent waters. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic near 18N16W to 08N47W. Aside from the convection described in the Tropical Waves section above, scattered moderate convection is noted within 60 nm on either side of the boundary. GULF OF MEXICO... Please see the Special Features section for more details on Potential Tropical Cyclone Four. A surface ridge reaches westward from the western Atlantic. Light to gentle winds and seas at 1 to 2 ft prevail over the northeastern and east-central Gulf. Outside the influence of Potential Tropical Cyclone Four, gentle to moderate with locally fresh E to SE winds and 2 to 4 ft seas prevail for the rest of the Gulf. For the forecast, Potential Tropical Cyclone Four will become a TS this afternoon moving to 24.4N 96.9W, inland to 26.3N 98.3W Sun morning as a TD, then become a remnant low and move to 27.5N 99.5W Sun afternoon, and dissipate Mon morning. Seas will peak to 13 ft with strongest winds. Heavy rains and tstms are expected over the SW and far NW Gulf over the weekend. CARIBBEAN SEA... Refer to the section above for details on the tropical wave moving across the eastern Caribbean. The Atlantic ridge associated with a 1026 mb Azores High continues to channel NE to E trades across the entire basin. Fresh to strong NE to ENE winds and seas of 6 to 8 ft are evident for the south-central basin, just north of Colombia. Gentle to moderate ENE to E winds and 2 to 4 ft seas are found over the northwestern and extreme southwestern basin. Moderate to fresh ENE to E winds and seas at 4 to 6 ft prevail for the remainder of the basin, including the Gulf of Honduras. For the forecast, surface ridging extending to the northern Caribbean along with the passage of a tropical wave currently moving across the eastern half of the basin will continue to support moderate to fresh trade winds in the eastern and central Caribbean, and fresh to strong winds in the south-central and portions of the SW Caribbean through today. Fresh to strong NE winds are also expected across the Windward Passage tonight and Sun night. The ridge will weaken Sun night through Tue, diminishing the winds across the region to gentle to moderate speeds. ATLANTIC OCEAN... Refer to the section above for details on the tropical wave moving across the eastern tropical Atlantic. A surface trough is enhancing showers activity between 50W-60W and S of 20N. To the N, an upper-level low at the north-central Atlantic near 29N48W is triggering scattered showers and thunderstorms N of 26N between 45W and 51W. The Atlantic ridge related to the 1028 mb Azores High is supporting light to gentle winds and seas at 2 to 4 ft N of 26N between 50W and the Georgia/Florida coast. To the SE, gentle to moderate NNE to ENE trades and 4 to 6 ft seas are evident from 10N to 26N between 30W and the Bahamas/Lesser Antilles, and north of 25N between the African coast and 50W. Gentle to moderate monsoonal and southerly winds with 5 to 8 ft seas in southerly swell prevail for the rest of the Atlantic Basin. For the forecast W of 55W, moderate to fresh easterly winds S of 25N through the weekend. Locally strong winds are likely N of Hispaniola and the approaches of the Windward Passage tonight and Sun night. The surface ridge will weaken on Sun evening into early next week, thus diminishing these winds to gentle to moderate speeds. $$ ERA/Mahoney