000 AXNT20 KNHC 241304 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Tue Aug 24 2021 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 1000 UTC. ...TROPICAL WAVES... A tropical wave is along 24W/25W, from 20N southward, moving W at 10 to 15 knots. A 1009 mb low pressure is along the wave axis near 08N. The wave is producing a concentrated area of showers and thunderstorms mainly from 06N-11N between 25W-30W. This convective activity has become a bit better organized during the overnight hours, and some additional development is possible over the next several days while this system moves westward to west-northwestward at 10 to 15 kt over the eastern tropical Atlantic. The latest Tropical Weather Outlook states that this system has a medium chance of tropical cyclone formation through 5 days. A tropical wave is along 44W, from 21N southward. The wave is moving W at 10 to 15 knots. A 1010 mb low pressure is analyzed near the northern end of the wave axis. Fresh to strong winds are noted per scatterometer data on the E side of the low center. Scattered moderate convection is seen from 20N-23N between 42W- 45W. Little development is expected during the next day or two due to marginally conducive ocean temperatures and strong upper- level winds. Afterwards, environmental conditions are expected to become more favorable for gradual development, and a tropical depression could form by the end of the week while the system moves northwestward to northward at 10 to 15 mph over the central Atlantic. The latest Tropical Weather Outlook gives this system a medium chance of tropical cyclone formation through 5 days. A weak tropical wave is approaching the Lesser Antilles with axis along 58W, from 19N southward. The wave is moving W 10 to 15 knots. Convection is limited near the wave axis. An active tropical wave is moving across the eastern Caribbean. Its axis is along 69W and extends from Dominican Republic to western Venezuela. The wave is producing scattered showers and thunderstorms, particularly from 10N-15N between 61W-73W. This convective activity is affecting the Windward Islands. The wave is also helping to induce scattered moderate to strong convection over western Venezuela. A broad area of low pressure is expected to form along the wave axis over the southwestern Caribbean Sea later this week. Thereafter, environmental conditions are forecast to be favorable for gradual development, and a tropical depression could form by the end of the week while the system moves west- northwestward to northwestward over the northwestern Caribbean Sea. This system has also a medium chance of tropical cyclone formation through 5 days according to the latest Tropical Weather Outlook. A second tropical wave is over the Caribbean Sea along 86W from 20N southward, moving westward 10 to 15 knots. The wave axis crosses northern Central America where is enhancing some shower and thunderstorm activity. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic Ocean through the coastal border sections of Mauritania and Senegal near 16N16W, then crosses just to the south of the Cabo Verde Islands, and continues westward to 14N30W to 13N40W to 08N46W. The ITCZ extends from 08N46W to 09N57W. Most of the convective activity across the region is related to the tropical waves, with the exception of a cluster of moderate convection near the Mauritania/Senegal border. ...GULF OF MEXICO... High pressure remains in control of the weather pattern across the Gulf waters producing mainly gentle to moderate winds. Seas are generally below 4 ft. The northern end of a tropical wave, with axis along 95W, is producing scattered showers and thunderstorms over the Bay of Campeche. Fresh to locally strong winds are also noted in that area. A surface trough is analyzed over the NE Gulf extending from the Florida Panhandle to SE Louisiana. Scattered showers and thunderstorms are also observed near the trough axis. For the forecast, high pressure will dominate the basin through Fri. Fresh winds will likely pulse west of the Yucatan Peninsula tonight and again Wed night due to local effects induced by a thermal trough. Increasing pressure gradient between high pressure over the Gulf waters and a possible tropical system over the NW Caribbean will result in fresh to strong easterly winds over the SE and south-central Gulf during the upcoming weekend. ...CARIBBEAN SEA... Two tropical waves are moving westward across the Caribbean Sea. Please, see the Tropical Waves section for details. The most recent scatterometer data provided observations of fresh to strong winds across most of the east and central Caribbean with fresh to locally strong NE winds across the Mona and Windward passages, and in the Gulf of Honduras. Seas are 8 to 10 ft near the coast of Colombia. Convection across the basin is related to the tropical waves. For the forecast, fresh to strong trade winds will dominate most of east and central Caribbean through midweek, with seas in the 8 to 10 ft range. Fresh to locally strong winds are also expected in the Windward passage through tonight. A tropical wave over the eastern Caribbean Sea is expected to form a broad area of low pressure over the southwestern Caribbean later this week. ...ATLANTIC OCEAN... Tree tropical waves are moving westward between the W coast of Africa and the Lesser Antilles. Please, see the Tropical Waves section for details. High pressure of 1022 mb is located near Bermuda at 33N64W. Another 1021 mb high pressure is centered south of the easternmost Azores near 33N25W. The pressure gradient between this system and lower pressures over W Africa supports an area of fresh to strong NE winds roughly from 19N-28N and E of 26W, including the Canary Islands. A frontal trough is between the high pressure systems. A large area of showers and thunderstorms has developed N of Hispaniola and covers mainly the waters from 21N-27N between 67W-72W. An upper-level low spinning near 24N71W is generating this convective activity. African dust has reached the Bahamas and South Florida producing hazy conditons and heat indices in the 100 to 105 degree range each afternoon. This will persist today. A surface trough, previously associated with the northern extent of a tropical wave, will move northward across the central Atlantic over the next 48-72 hours. Fresh to strong E to SE winds and seas of 8 to 11 ft will follow the trough. A tropical depression could form along the trough axis by the end of the week. For the forecast W of 65W: High pressure located near Bermuda will dominate the forecast region through at least Wed. Fresh to locally strong winds are expected N of Hispaniola including the approaches to the Windward Passage through tonight. The above mentioned surface trough is forecast to approach from the east on Thu. The pressure gradient could increase some across the SW N Atlantic tonight and Wed between high pressure located just N of Bermuda and the approaching surface trough. Then, expect increasing winds across the waters between Cuba and the Bahamas by the end of the week as a tropical system develops over the NW Caribbean. $$ GR