000 AXNT20 KNHC 202325 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sun Aug 21 2022 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 1800 UTC surface analysis and satellite imagery through 2300 UTC. ...SPECIAL FEATURES... Potential Tropical Cyclone Four remains disorganized. It is centered near 24.4N 97.3W at 20/2100 UTC or 90 nm S 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. The forecast track brings this system across northeastern Mexico and southern Texas this evening and tonight. Some development is possible during the next few hours, but the chances of this system becoming a tropical cyclone are decreasing. The disturbance is expected to produce total rainfall amounts of 1 to 3 inches, with isolated totals of 5 inches, along the northeastern coast of Mexico across the state of Tamaulipas today. These rains could produce isolated flash flooding across coastal northeast Mexico. Rainfall amounts of less than an inch are expected farther to the north across far South Texas. The combination of storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. Swells generated by this system are forecast to affect eastern Mexico and southern Texas through early Sunday. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather forecast 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... A tropical wave located near the west coast of Africa along 21W is producing disorganized showers and thunderstorms from 10N to 17N between 17W and 25W. A 1008 mb low pressure is analyzed along the wave axis near 15N. Environmental conditions are expected to be marginally conducive for gradual development of this system while it moves westward to west-northwestward at 15 to 20 mph across the eastern and central tropical Atlantic during the early to middle part of next week. Currently, this tropical wave has a low chance of tropical cyclone development over the next five days. A tropical wave previously located along 33W is relocated near 40W based on the Tropical Wave Diagnostics. It axis extends from 20N southward. Limited convection is near the wave axis. A tropical wave is entering the central Caribbean, and extends along 70W/71W from Dominican Republic to western Venezuela. It is moving west at 15-20 kt. The wave is enhancing some convective activity over Hispaniola and western Puerto Rico as well as over the eastern Caribbean and parts of Venezuela. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic at the coast of Mauritania near 18N16W then continues SW to 11N30W to 08N46W. The ITCZ extends from 08N46W to the coast of Suriname. Aside from the convection described in the Tropical Waves section above, scattered moderate convection is from 06N to 14N between 27W and 35W. Scattered showers, with embedded thunderstorms, are E of the Windward Islands to about 55W. GULF OF MEXICO... Please see the SPECIAL FEATURES section for more details on Potential Tropical Cyclone Four. The most recent scatterometer data indicate strong to near-gale force SE winds over the western Gulf in association with Potential Tropical Cyclone Four. Elsewhere, a gentle to moderate anticyclonic flow prevails under the influence of the western periphery of the Bermuda-Azores High that extends across Florida into the Gulf region. Seas are 6-8 ft over the west-central Gulf based on a recent altimeter pass. Seas of 3-5 ft are seen elsewhere across the western Gulf, with seas of 1-3 ft over the eastern half of Gulf waters, with the exception of 3-4 ft across the Straits of Florida, and in the Yucatan Channel. For the forecast, Potential Tropical Cyclone Four will move inland to 26.3N 98.6W Sun morning, and dissipate Sun afternoon. Maximum seas of about 9 ft will continue into this evening. Heavy squalls associated with this system will continue over the far western Gulf through late tonight. Winds and seas will subside by early Sun. Weak ridging will prevail over the Gulf early next week, leading to gentle to moderate winds. CARIBBEAN SEA... The pressure gradient between the Bermuda-Azores High and the Colombian low supports fresh to strong trades over the south- central Caribbean. Mainly moderate to locally fresh NE to E winds prevails elsewhere across the east and central Caribbean, with gentle to locally moderate winds over the NW Caribbean. Moderate to fresh NE winds are noted across the Windward Passage based on scatterometer data. Seas are generally 3 to 5 ft, with the exception of 5 to 7 ft over the south-central Caribbean. For the forecast, surface ridging north of the area along with the passage of a tropical wave currently over the central Caribbean will continue to support moderate to fresh trade winds in the eastern and central Caribbean through tonight. Fresh to locally strong NE winds are 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... The Atlantic remains dominated by the Bermuda-Azores High centered just over the Azores near 39N29W. A weak surface trough is analyzed from 30N53W to 24N54W. Scattered showers are near the trough axis. Gentle to moderate anticyclonic flow dominates most of the forecast waters. Winds increase to moderate to fresh speeds S of 24N between 70W and 76W, including the Windward Passage. W of 35W, seas are generally 4-6 ft across the Atlantic, as confirmed by satellite altimeter data. However, seas of 6-8 ft are noted south of the Cabo Verde Islands in a fresh southerly wind flow. For the forecast W of 55W, the subtropical surface ridge extends from Bermuda to central Florida. The ridge will change little through Sun night, supporting moderate to fresh easterly winds S of 25N through the remainder of this weekend. Fresh to locally strong winds are likely N of Hispaniola and the approaches of the Windward Passage tonight and Sun night. A weak surface trough will move westward from 65W to 75W Mon and Mon night. The trough will weaken the ridge, thus diminishing winds to gentle to moderate speeds. $$ GR