006 AXNT20 KNHC 201037 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Sun Aug 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 1030 UTC. ...SPECIAL FEATURES... Tropical Depression Six is centered near 16.8N 52.9W at 20/0900 UTC or 590 nm E of the Northern Leeward Islands, moving W at 13 kt. Estimated minimum central pressure is 1007 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. The low level circulation is completely exposed due to strong westerly shear impacting the system and keeping the thunderstorm activity 60 to 90 nm east of the center. The depression will continue west through Monday, then turn more to the west-northwest. T.D. Six has likely already peaked, and will likely become post-tropical remnant low in 36 hours and dissipate by 48 hours if not sooner. 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 Tropical Depression Six NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Gale Warning (AL98): A broad area of low pressure located several hundred miles west-northwest of the Cabo Verde Islands. A 1005 mb low is analyzed near 19N38W, with tropical wave along 38W. Scattered moderate convection is from 19N-26N between 34W-39W. A recent scatterometer satellite pass indicate winds were approaching gale force within 60 nm on the north side of the low pressure, and a gale warning is in effect accordingly. Seas are expected to be as high as 14 ft in the area of strong winds. Environmental conditions still appear generally favorable for development, and a short-lived tropical depression is likely to form later today or tonight while it moves west- northwestward at about 10 kt over the central tropical Atlantic. By Monday, upper-level winds are forecast to strengthen over the system, and further development is not expected. This disturbance has a high chance of formation through 48 hours. Eastern Caribbean (AL90): An area of low pressure over the far eastern Caribbean is producing showers and thunderstorms with some signs of organization. The low is analyzed near 13N63W, with tropical wave extending along 63W. Scattered to numerous moderate convection prevails from 11N-16N between 59W-67W. Seas to 10 ft are noted in the eastern Caribbean E of 66W. Additional development of this system is expected, and a tropical depression is likely to form during the early or middle part of this week. The system is forecast to move westward at 10 to 15 kt over the eastern and central Caribbean during the next couple of days, then turn northward and move over the southwestern Atlantic by midweek. Regardless of development, heavy rainfall is possible over portions of the Lesser Antilles during the next couple of days. Interests in the eastern and central Caribbean should monitor the progress of this system. This disturbance has a medium chance of formation through 48 hours. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details. ...TROPICAL WAVES... A new tropical wave extends from 06N to 21N along 21W, moving west at 10 to 15 kt. Scattered moderate isolated strong convection is from 08N to 18N and E of 27W. Environmental conditions appear conducive for gradual development of this system, and a tropical depression could form later this week while it moves west- northwestward across the eastern tropical Atlantic. A western Caribbean tropical wave is evident along 85W south of 22N, moving west at 10 to 15 kt. Scattered moderate convection are noted W of 82W. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the east Atlantic near 14N17W to AL98. Other than the convection already discussed in the Special Features and Tropical Wave sections, no additional significant convection is noted. GULF OF MEXICO... A surface trough is moving across the eastern Gulf enhancing convection E of 86W. A weak 1015 mb high pressure is evident over the northwest Gulf near 29N93W. Moderate winds are likely over the Straits of Florida and the west coast of the Yucatan peninsula, but otherwise this pattern is supporting light to gentle breezes and slight seas across the basin. For the forecast, the surface ridge over the Gulf waters will support mostly gentle to moderate winds and slight seas across the basin through tonight. Looking ahead, an area of disturbed weather located over the Straits of Florida and the southern Florida peninsula will move into the Gulf of Mexico later today, where a broad area of low pressure is expected to form early this week. Some slow development of this system could occur thereafter as it moves westward at about 15 to 20 kt, and a tropical depression could form as it approaches the western Gulf of Mexico coastline by Tuesday. This system has a low chance of development in 48 hours and a medium chance in 7 days. CARIBBEAN SEA... Refer to the section above for details on AL90, currently located across the eastern Caribbean. W of AL90, the pressure gradient between the subtropical Atlantic ridge and lower pressure over Colombia and Panama is supporting fresh to strong E to NE winds in the south-central Caribbean off the coast of Colombia, where seas are currently 4 to 6 ft. Elsewhere in the basin, trades are mainly moderate with seas of 3-6 ft. Scattered showers and tstorms are noted near Jamaica and in the lee of E Cuba. For the forecast, AL90 could develop into a tropical depression during the early or middle part of this week. The system is forecast to move westward at 10 to 15 kt over the eastern and central Caribbean during the next couple of days, then turn northward and move over the southwestern Atlantic by midweek. Regardless of development, heavy rainfall, strong to near gale winds and moderate to rough seas are possible across the eastern Caribbean during the next couple of days. This system has a medium chance of development in 48 hours and a high chance in 7 days. ATLANTIC OCEAN... Refer to the sections above for details TD Six, invests, and tropical waves moving across the basin. The subtropical ridge dominates the tropical Atlantic. The pressure gradient between the ridge and all of our disturbances to the south is driving a band of fresh to locally strong trades across the basin from 18N to 25N. North of 25N, trades are mainly moderate. Farther south, winds are gentle to moderate from various directions. Seas are 4-7 ft across the basin. For the forecast west of 55W, TD Six will move to 17.0N 54.8W this afternoon, become a remnant low and move to 17.3N 56.8W Mon morning, and dissipate Mon afternoon. Fresh to strong tradewinds will pulse off Hispaniola and the Windward Passage each evening into early next week. Fresh tradewinds south of 25N will persist through the weekend. $$ ERA