000 AXNT20 KNHC 211756 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Wed Jun 21 2023 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 1200 UTC surface analysis and satellite imagery through 1500 UTC. ...SPECIAL FEATURES... Tropical Storm Bret: Tropical Storm Bret is centered near 13.0N 52.5W at 21/1500 UTC or 408 nm E of Barbados, and moving W at 12 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Seas 12 ft or greater are observed within 120 NM NE quadrant, 60 NM SE quadrant, 30 NM SW quadrant, and 90 NM NW quadrant with seas to 16 ft. Scattered to numerous moderate convection is noted from 11N-16N between 50W and 54W. Bret is expected to continue moving west for the next several days. On the forecast track, the center of Bret is expected to approach the Lesser Antilles on Thursday, move across the Lesser Antilles late Thursday and Thursday night, and then move westward across the eastern and central Caribbean Sea Friday and Saturday. Through Saturday, storm total rainfall amounts of 3 to 6 inches with maximum amounts of 10 inches are possible across portions of the Lesser Antilles from Guadeloupe south to St. Vincent and the Grenadines, including Barbados. The heavy rainfall could lead to flash flooding, especially across areas of higher terrain. Urban flooding is also possible. Please read the latest HIGH SEAS FORECAST issued by National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, the latest NHC Public Advisory at https://www.nhc.noaa.gov/text/MIATCPAT3.shtml and Forecast/ Advisory at https://www.nhc.noaa.gov/text/MIATCMAT3.shtml for more details. Invest Area (AL93): A tropical wave extends along 37W from 03N to 15N, moving west at about 15 kt. A 1010 mb low is analyzed along the wave near 10.4N37.9W. Scattered showers and isolated thunderstorms are noted up to 165 nm west of the wave axis. Strong winds are noted in the northern semicircle of the low, where seas are in the 6-8 ft range. Environmental conditions appear conducive for further development of this system, and a tropical depression will likely form during the next couple of days. The latest Tropical Weather Outlook assigns a high chance of tropical cyclone formation in the next 48 hours, and over the next seven days. Refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... A new tropical wave just emerged off the coast of west Africa. This tropical wave extends along 16W from 02N to near the Gambia coast, moving west at 5 to 10 kt. Scattered moderate to isolated strong convection is from 02N to 11N between Sierra Leone/Liberia and 23W. A Caribbean tropical wave extends from east-central Venezuela through the northern Windwards Islands along 62W, and is moving west at 10-15 kt. Widely scattered showers are observed from 10N to 15N between 57W and 65W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near the city of Banjul in Gambia, through Invest Area AL93 to 10N43W. No ITCZ is currently present in the Atlantic. Scattered moderate convection is depicted from 11N-13N between 30W and 36W. The eastern end of the east Pacific Monsoon Trough is producing scattered showers and thunderstorms near the Panama coast in the Carribbean Sea. ...GULF OF MEXICO... Cluster of showers and thunderstorms associated with a surface trough are moving southeast in the northeastern Gulf. Fresh to strong localized winds and 4 to 6 ft seas are present near this activity. Fresh southerly winds with seas at 3 to 5 ft are located at the south-central Gulf north of the Yucatan Peninsula. Elsewhere, a high pressure ridge continues to dominate the basin. Anticyclonic winds are mostly gentle to moderate. Seas are generally 3 to 4 ft across the basin. For the forecast, the high pressure ridge will generally persist into the upcoming weekend. Fresh winds will pulse north of the Yucatan Peninsula each night through the forecast period as a diurnal trough develops and moves offshore. Elsewhere, gentle to moderate southerly winds will prevail, locally fresh at times. Smoke from agricultural fires in Mexico will produce hazy skies over the central and western Gulf for at least the next day or two. ...CARIBBEAN SEA... Please refer to the sections above for information on Tropical Storm Bret and the tropical waves moving across the basin. Scattered showers and isolated thunderstorms are currently affecting the coasts of Honduras and Nicaragua due to an upper level trough. The pressure gradient between the subtropical high pressure and lower pressure over northern Colombia is supporting fresh to strong trade winds in the central Caribbean, where seas are in the 7-9 ft range. Winds are gentle to moderate elsewhere, with 3-6 ft seas. For the forecast, Tropical Storm Bret will strengthen a little as it moves to near 13.2N 54.4W this evening with maximum sustained winds 55 kt gusts 65W and maintain intensity as it nears 13.5N 57.1W early Thu, then approaches the Lesser Antilles near 13.9N 60.1W early Thu evening as it tracks west-northwest. Bret will move into the eastern Caribbean Sea Thu night reaching near 14.3N 63.5W early on Fri as it begins to weaken. Bret is forecast to reach near 14.6N 67.1W Fri evening with maximum sustained winds 45 kt gusts 55 kt and to near 14.7N 70.7W early Sat and dissipate by early Sun. The low pressure (AL93), that is currently over the eastern Atlantic may move across the tropical N Atlantic waters this weekend as a possible tropical cyclone. Otherwise, fresh to strong E trades will persist across the central Caribbean through early Thu. Moderate to fresh E to SE winds are expected in the Gulf of Honduras through late tonight, increase to fresh to strong through Thu, then to near gale Thu night and diminish back to fresh to strong Fri into early Sat. ...ATLANTIC OCEAN... Please refer to the Special Features section for information on Tropical Storm Bret and Invest Area AL93. Clusters of showers and thunderstorms are depicted from central Bahamas through southwest of Bermuda in association with low-level convergence and mid-level divergence. Moderate to fresh southerly winds and seas of 4 to 6 ft are depicted north of 29N between 74W and the Florida/Georgia coasts. Otherwise, a large 1022 mb high pressure in the central Atlantic continues to support gentle to moderate winds N of 24N and moderate to fresh winds south of 24N. Seas are 2 to 5 ft outside from Tropical Storm Bret and Invest AL93. For the forecast W of 55W, the aforementioned large high pressure will continue to control the weather regime throughout the rest of the forecast period. Moderate to fresh S to SW winds north of 27N and west of 70W will change little through the end of the week. Otherwise, mainly gentle to moderate anticyclonic winds will prevail the next several days, except locally fresh offshore N Hispaniola and offshore N Florida. AL93 may move across the tropical N Atlantic waters this weekend as a possible tropical cyclone. $$ Forecaster KRV/Chan