000 AXNT20 KNHC 221127 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Sat Jul 22 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 1115 UTC. ...SPECIAL FEATURES... Tropical Storm Don is centered near 38.3N 49.6W at 22/0900 UTC or about 530 nm SSE of Cape Race, Newfoundland moving NW at 12 kt. Estimated minimum central pressure is 998 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Satellite imagery shows numerous moderate convection confined within 75 nm of the center in the SE quadrant and within 60 nm of the center in the NE quadrant. This convection denotes a wide convective band that just about wraps around the system's center. Don is forecast to turn to the north later today, followed by a turn to the northeast on Sun. Some slight strengthening is possible today. however, weakening is forecast to begin by tonight or on Sun morning. Don is expected to become a post-tropical cyclone on Sun or Sun night. 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. Don Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Central Tropical Atlantic (AL95): A 1012 mb low pressure is in the central tropical near 12N41W in the central Atlantic. Easterly wind shear is displacing deep convection within 180 nm west of the system center. This convection consist of the numerous moderate to isolated strong type from 11N to 13N between 42W-45W. Newly formed isolated moderate convection is within 30 nm of 12N42W. Fresh, to at times strong, northeast to east winds are north of the low along with seas of 4-7 ft. Although environmental conditions are only marginally conducive, some additional gradual development is anticipated and this system will likely become a tropical depression by early next week while it moves westward across the tropical Atlantic. Interests in the Lesser Antilles should monitor the progress of this system. The disturbance has a medium chance of development over the next 48 hours. Refer to the latest Tropical Weather Outlook at www.hurricanes.gov for more details. Gale Warning E of 35W: The strong pressure gradient between a 1030 mb high pressure near the Azores and lower pressures over NW Africa has induced fresh to near gale-force northerly winds in the eastern Atlantic, mainly north of 17N and east of 25W. The strongest winds are present off the coast of Morocco and Western Sahara and in the water passages of the Canary Islands. Seas in the affected area are 6-10 ft. Meteo-France is forecasting frequent gusts to gale force and rough to very rough seas in the Agadir and Canarias Marine Zones until 23/0300 UTC. Please read the High Sea Forecast and Warning at https://wwmiws.wmo.int for more details. ...TROPICAL WAVES... An eastern Atlantic tropical wave has its axis along 31W/32W from 05N to 19W. It is moving westward at 10-15 kt. Isolated showers and thunderstorms are within 240 nm west and 120 nm east of the wave from 06N to 12N. A central Caribbean tropical wave has its axis along 81W and south of 19N. It is moving westward at 10-15 kt. The interaction between the wave axis and the eastern Pacific monsoon trough is producing scattered showers and a few thunderstorms along the coast of southern Costa Rica and along the coast of northern Panama. ...MONSOON TROUGH/ITCZ... The monsoon trough axis reaches the Atlantic through the coast of Mauritania near 19N16W. It continues southwestward to 11N23W, then to 13N34W to the SPECIAL FEATURES low pressure near 12N41W and to 09N47W. Scattered moderate convection is from 04N to 11N and east of 24W to the coast of Africa. ...GULF OF MEXICO... A trough is over the Bay of Campeche from 22N92W to 19N93W. Isolated showers and thunderstorms are presently over the central and western sections of the Bay of Campeche. Weak high pressure dominates the Gulf waters, with the associated gradient resulting in moderate or weaker winds and 1-3 ft seas. For the forecast, weak high pressure centered near the eastern Gulf will remain remain dominate into early next week. This will support mainly gentle to moderate winds, except over the eastern Bay of Campeche where winds will be enhanced by a thermal trough that will emerge off the Yucatan Peninsula during the overnight hours. ...CARIBBEAN SEA... Divergence aloft in the western Caribbean Sea in combination with plenty of available tropical moisture support scattered moderate to isolated strong convection, mainly west of west of 84W and south of 21N. The remainder of the Caribbean Sea is under the influence of a subtropical ridge positioned near the Azores. Dry Saharan dust covers most of the eastern and central Caribbean, resulting in drier conditions, above normal daily temperatures and reduced visibility. The pressure gradient between the ridge and lower pressures in NW South America continue to sustain fresh to strong easterly trade winds in the central Caribbean. Overnight partial ASCAT data depicts some of these winds. The strongest winds are in the south-central Caribbean. In the remainder of the basin, moderate or weaker winds prevail. Wave heights are in the 8-11 ft range over the central Caribbean and much lower in the 2-6 ft range elsewhere. For the forecast, the aforementioned pressure gradient will maintain strong trades across the central Caribbean through tonight. Winds should diminish slight to fresh to strong Sun through Tue night. Fresh to locally strong trades will develop over the Gulf of Honduras Sun through Mon. Low pressure, AL95, well east of the region is forecast to move into Atlantic waters E of the Lesser Antilles early next week, possibly as a tropical cyclone. Expect increasing wind and seas over these waters in association with this low pressure system. ...ATLANTIC OCEAN... Please see the SPECIAL FEATURES section for information on Tropical Storm Don in the north-central Atlantic, gale winds in the eastern Atlantic, and INVEST 95L in the central Atlantic. An upper-level trough between Bermuda and Puerto Rico is producing scattered showers and thunderstorms north of 22N and between 61W-67W. The rest of the tropical Atlantic is under the dominance of a 1030 mb subtropical ridge centered near the Azores. A large outbreak of Saharan dust (SAL) continues to propagate across the central and eastern Atlantic suppressing the development of showers and thunderstorms. Numerous moderate convection, aided by a broad upper-level trough, is just north of the discussion area west of 74W. This activity is shifting eastward, and should remain quite active through at least this evening. The pressure gradient between the aforementioned ridge that extends into the SW Atlantic and lower pressures over the eastern United States is leading to moderate to fresh southwest to west winds north of 27N and west of 66W. Seas over these waters are 4-7 ft. Moderate easterly winds and 2-4 ft seas are noted between the SE Bahamas, northern Hispaniola and NE Cuba. Elsewhere west of 55W, light to gentle anticyclonic winds and slight seas prevail. Over the remainder of the tropical Atlantic moderate or weaker winds and slight to moderate seas are prevalent. For the forecast west of 55W, weak high pressure of 1016 mb centered near 24N67W will change little through the weekend. Fresh trades just north of Hispaniola and over the Windward Passage will diminish tonight. Elsewhere across forecast waters, winds will be moderate or weaker into next week. $$ Aguirre