000 AXNT20 KNHC 200842 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Tue Jun 20 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 0600 UTC surface analysis and satellite imagery through 0730 UTC. ...SPECIAL FEATURES... Tropical Storm Bret: As of 09 UTC, Tropical Storm Bret is centered near 11.7N 44.7W at 20/0900 UTC or 980 nm E of the Southern Windward Islands moving W at 15 kt. Estimated minimum central pressure is 1008 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Seas 12 ft or greater extend up to 60 nm in the N semicircle with peak seas of 13 ft. As Bret interacts with subtropical high pressure to the north, strong winds and rough seas in excess of 8 ft reach as far north as 17N. Numerous moderate with isolated strong convection is observed from 09N to 14N between 41W and 51W. Although Bret remains a well-organized tropical cyclone on satellite imagery, its overall appearance has changed little since yesterday evening. The cloud pattern consists of a developing CDO with some banding features mainly over the eastern portion of the circulation. On the forecast track, the system should be approaching the Lesser Antilles by late this week. Bret is forecast to initially strengthen and then move across the Lesser Antilles near hurricane intensity on Thursday and Friday, bringing a risk of flooding from heavy rainfall, strong winds, and dangerous storm surge and waves. Given the larger than usual uncertainty in the track forecast, it is too early to specify the location and magnitude of where these hazards could occur. However, everyone in the Lesser Antilles, Puerto Rico, and the Virgin Islands should closely monitor updates to the forecast for Bret and have their hurricane plan in place. Please read the latest HIGH SEAS FORECAST issued by National Hurricane Center at wed-site 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): A tropical wave in the Eastern Atlantic extends along 31W/32W from 02N to 15N, moving W at around 15 kt. A 1011 mb low pressure is analyzed along the wave axis near 08.5N31.5W. Winds are currently fresh to locally strong north of the low-pressure center, generating 5-7 ft seas. Scattered moderate with isolated strong convection is observed from 04N to 12N between 30W and 39W. Environmental conditions appear favorable for further development of this system, and a tropical depression will likely form later this week while the system moves westward at 10-15 kt across the eastern and central tropical Atlantic. The current tropical weather outlook assigns a medium (60%) probability of formation through the next 48 hours, and a high (70%) probability over the next seven days. Please refer to the latest Tropical Weather Outlook at www.hurricanes.gov, for more details. ...TROPICAL WAVES... An Atlantic tropical wave extends along 56W from near central Suriname at 01N to 16N, moving west at 20-25 kt. The northern portion of the wave has passed NDBC buoy 42058, which is currently reporting 20 kt NE winds and 5 ft seas. Associated convection remains isolated and weak. A tropical wave is moving from the central to the western Caribbean Sea, extending along 78W S of 15N to across eastern Panama and into the eastern tropical Pacific Ocean, moving west at around 25 kt. No significant convection is occurring near this wave. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 16N16W to Invest Area 93L near 08.5N31.5W to 10N39W. No ITCZ is currently present. All significant convection is described in the Special Features section. GULF OF MEXICO... The subtropical Atlantic ridge extends across the Straits of Florida to the NW Gulf waters. Scattered showers and thunderstorms are noted in the north-central and NE Gulf, particularly within 180 nm of the coast. The pressure gradient between the ridge and lower pressure over Mexico and the southern US, along with a surface trough located offshore of the western Yucatan Peninsula is supporting moderate to fresh anticyclonic winds across the basin, except gentle to moderate in the SE Gulf through the Straits of Florida. Seas are mainly 3-5 ft per recent buoy observations, locally higher near the convection, and except 1-3 ft in the SE Gulf. Smoke due to agriculture fires over Mexico may be reducing visibilities along the coast of Mexico and the western Bay of Campeche where the latest SAB analysis indicates a low to medium concentration. 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 approach the Lesser Antilles late this week. The gradient between subtropical high pressure and lower pressure over the SW Caribbean is supporting strong easterly trade winds in the central Caribbean, where seas are in the 6-10 ft range. Fresh SE winds are noted in the Gulf of Honduras. Gentle winds are noted in the lee of Cuba and approach to the Windward Passage, where seas are 1-3 ft. Winds are moderate to fresh elsewhere, with 3-6 ft seas. For the forecast, Tropical Storm Bret is currently near 11.7N 44.7W 1008 mb at 5 AM EDT moving W at 15 kt. Maximum sustained winds 35 kt gusts 45 kt. Bret will move to 12.1N 46.9W this afternoon, 12.6N 49.7W Wed morning, 13.1N 52.4W Wed afternoon, strengthen to a hurricane near 13.5N 55.0W Thu morning, 13.9N 57.8W Thu afternoon, and weaken to a tropical storm near 14.3N 60.4W Fri morning. Bret will change little in intensity as it moves to 15.0N 65.8W early Sat. 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. An unsettled weather pattern remains over the SW N Atlantic mainly W of 74W where scattered showers and isolated thunderstorms are occurring. Additional isolated activity is between 60W and 74W. A 1025 mb high pressure centered near 32N45W is the dominate feature across the basin. North of 22N, anticyclonic winds are gentle to moderate with 3-6 ft seas. South of 22N and outside of the immediate impacts from Tropical Storm Bret, moderate to fresh NE-E winds and 5-7 ft seas are observed, except for gentle winds S of 10N and W of 35W with 3-5 ft seas. For the forecast W of 55W, Tropical Storm Bret is currently near 11.7N 44.7W 1008 mb at 5 AM EDT moving W at 15 kt. Maximum sustained winds 35 kt gusts 45 kt. Bret will move to 12.1N 46.9W this afternoon, 12.6N 49.7W Wed morning, 13.1N 52.4W Wed afternoon, strengthen to a hurricane near 13.5N 55.0W Thu morning, 13.9N 57.8W Thu afternoon, and weaken to a tropical storm near 14.3N 60.4W Fri morning. Bret will change little in intensity as it moves to 15.0N 65.8W early Sat. Otherwise, Bermuda high pressure extends a ridge SW through the central Bahamas to the SE Gulf of Mexico, and will continue to dominate through mid-week. A weak cold front off the SE US coast will linger and gradually dissipate through the early part of the week with locally fresh winds E of it tonight. Mainly gentle to moderate anticyclonic winds will prevail the next several days, locally fresh offshore N Hispaniola and offshore N Florida. $$ Lewitsky