000 AXNT20 KNHC 202322 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 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 1800 UTC surface analysis and satellite imagery through 2300 UTC. ...SPECIAL FEATURES... Tropical Storm Bret: Tropical Storm Bret is centered near 12.2N 48.6W at 20/2100 UTC or about 725 nm E of the Windward Islands moving W or 280 degrees at 15 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Seas 12 ft or greater are observed within 60 nm N semicircle and 30 nm SE quadrant of center with seas to 15 ft. A burst of deep convection developed over Bret's center during the past several hours, with a convective band wrapping around the east side of the circulation. On the forecast track, the center of Bret is expected to move across portions of the Lesser Antilles Thursday afternoon and Thursday night, and then move across the eastern Caribbean Sea on Friday. Bret is a little stronger. Additional strengthening is forecast during the next day or so, and Bret is expected to be a tropical storm when it reaches the Lesser Antilles, bringing a risk of flooding from heavy rainfall, strong winds, and dangerous waves along the coast. Given the uncertainty in the track and intensity forecasts, it is too early to specify the location and magnitude of where Bret's associated hazards could occur. A Tropical Storm Watch has been issued for Barbados, and additional watches are likely for other islands within the Lesser Antilles later tonight. Please read the latest HIGH SEAS FORECAST issued by National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest T.S. Bret Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Invest Area (AL93): Shower and thunderstorm activity has diminished during the past several hours in association with a tropical wave located several hundred miles southwest of the Cabo Verde Islands. Its axis is along 34W S of 15N moving W at 10 to 15 kt. A 1011 mb low pressure is analyzed along the wave axis near 09.5N34W. Currently, convection is limited. However, environmental conditions appear conducive for further development of this system, and a tropical depression will likely form during the next couple of days while the system moves westward at 10 to 15 kt across the eastern and central tropical Atlantic. The latest Tropical Weather Outlook gives this system a high chance of tropical cyclone formation in the next 48 hours, as well as over the next seven days. Refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... A tropical wave is approaching the Lesser Antilles. Its axis is along 58W extending southward into Guyana, and moving W at 15 to 20 kt. Scattered moderate convection is near the northern end of the wave axis from 12N-16N between 56W and 60W. A tropical wave is near 80W from 14N southward across Panama into the East Pacific region, moving W at 15 to 20 kt. The wave appears to enhance convection over parts of Panama. ...MONSOON TROUGH/ITCZ... A monsoon trough extends SW from the coast of Senegal near 15N17W to a 1011 mb low pressure located 09.5N34W. A large cluster of moderate to strong convection is noted along the W coast of Africa likely associated with the next tropical wave. This strong convective activity is affecting mainly Sierra Leone, and covers the area from 05N-11N between 10W-15.5W. No ITCZ is present based on the latest analysis. ...GULF OF MEXICO... A cold front is over the NE Gulf, and extends from northern Florida near 30N82.5W to SE Louisiana. Numerous showers and thunderstorms are occurring near the frontal boundary, and over much of the State of Florida. S of the front to about 27N moderate to fresh SW winds and seas of 5-7 ft are noted, with higher winds near thunderstorms. Elsewhere, the Atlantic ridge extends across south-central Florida into the Gulf waters. The pressure gradient between the ridge and lower pressure inland Mexico supports moderate to fresh southerly winds across the western half of the Gulf, and a gentle to moderate anticyclonic flow across the eastern half of the Gulf S of 27N. Seas are generally 4-6 ft based on altimeter data, except 1-3 ft over the SE Gulf. For the forecast, high pressure extending from the Straits of Florida to the upper Texas coast will generally persist through the week and 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 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 Special Features section for information on Tropical Storm Bret, which is forecast to move across portions of the Lesser Antilles Thursday afternoon and Thursday night. The most recent satellite derived wind data provide observations of fresh to strong trade winds across the central Caribbean. Seas are 8-11 ft within these winds based on altimeter data. Moderate to fresh trades dominate the eastern Caribbean with seas of 4-6 ft. Moderate to locally fresh E winds are noted in the Gulf of Honduras with seas of 3-5 ft. Gentle to moderate winds prevail elsewhere, except in the lee of Cuba where light to gentle winds are seen. Scattered showers and thunderstorms are noted over parts of Central America and the Greater Antilles. For the forecast, Tropical Storm Bret will begin to gradually strengthen as it moves to near 12.3N 49.2W this evening, to near 12.7N 51.9W Wed morning with maximum sustained winds 45 kt gusts 50 kt, to near 13.2N 54.5W Wed evening, to near 13.6N 57.3W early Thu with maximum sustained winds 55 kt gusts 65 kt. Bret is forecast to maintain its intensity as it approaches the Lesser Antilles Thu evening and move into the eastern Caribbean Sea near 14.2N 63.6W early on Fri. Bret is forecast to begin to weaken as it nears 14.4N 70.4W early Sat with maximum sustained winds 45 kt gusts 55 kt and dissipate by early on Mon. Otherwise, the pressure gradient between the Bermuda High and the Colombian Low will support fresh to strong E trades across the central Caribbean through early Thu. Moderate to fresh E winds are expected in the Gulf of Honduras. ...ATLANTIC OCEAN... Please refer to the Special Features section for information on Tropical Storm Bret and Invest Area AL93 located in the eastern Atlantic Ocean. A surface trough is an analyzed E of Florida and runs from 31N78W to near Lake Okeechobee, Florida. Showers and thunderstorms are near the trough axis and over much of Florida. Gentle to moderate S winds are noted on the E side of the trough to about 70W. The Bermuda-Azores high dominates the remainder of the Atlantic forecast waters with a 1025 mb high center near 31N44W. The pressure gradient between the high pressure and T.S. Bret is resulting in an area of moderate to fresh NE to E winds roughly from 12N-21N between 38W and 55W with seas of 6-8 ft. Gentle to moderate anticyclonic flow is noted elsewhere, with light to gentle winds near the high pressure center. Outside of Bret, and E of 70W, seas are generally 4-6 ft, and 2-4 ft W of 70W and E of the Bahamas. For the forecast W of 55W, broad high pressure ridging extending southwest across the area will continue to control the weather regime during the rest of the forecast period. Moderate to fresh south to southwest winds N of 27N and W of 70W will change little through the end of the week. Otherwise, mainly gentle to moderate anticyclonic winds will prevail the next several days, locally fresh offshore N Hispaniola and offshore N Florida. $$ GR