000 AXNT20 KNHC 220007 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Wed Sep 21 2022 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 2140 UTC. ...Updated information on Special Features and Tropical Waves sections... ...SPECIAL FEATURES... Major Hurricane Fiona is centered near 25.9N 71.54 at 22/0000 UTC or 525 nm SW of Bermuda moving N at 8 kt. Estimated minimum central pressure is 934 mb. Maximum sustained wind speed is 115 kt with gusts to 140 kt. Scattered to numerous moderate to strong convection is within 90 nm of the center of Fiona. Scattered moderate to strong convection is elsewhere from 22N to 30N between 62W and 74W. Seas are peaking near 42ft. Fiona will remain over warm waters in a moist and unstable air mass for the next 48 hours. In this environment, some strengthening is still possible within the next day or so, though eyewall replacement cycles could cause some intensity fluctuations. The current forecast track shifts Fiona north of 32N by Thu night. 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 NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Tropical Storm Gaston is centered near 39.0N 40.0W at 21/2100 UTC or 610 nm W of the Azores moving NE at 12 kt. Estimated minimum central pressure is 1000 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Scattered moderate and isolated strong convection is noted from 28N and 42W between 35W and 42W. Please read the latest NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. A tropical wave is producing shower and thunderstorm activity near the southern Windward Islands and extreme southeastern Caribbean Sea. The system continues to show signs of organization, and it will likely become a tropical depression within the next couple of days. The disturbance is forecast to move west-northwestward across the eastern Caribbean Sea during the next day or two, and be over the central Caribbean this weekend. Regardless of development, locally heavy rainfall and gusty winds are forecast to affect the Windward Islands tonight, and northern Venezuela, northeastern Colombia, and the ABC island chain during the next couple of days. There is a high chance of tropical cyclone formation over the next 48 hours. Please refer to the latest Atlantic Tropical Weather Outlook at hurricanes.gov for more details. Showers and thunderstorms located near the west coast of Africa are associated with a tropical wave that is forecast to move over the far eastern Atlantic waters on Thursday. Thereafter, environmental conditions are forecast to be conducive for some development, and a tropical depression could form by this weekend while the system moves slowly northward, between west Africa and the Cabo Verde Islands. The chance of tropical cyclone formation during the next 48 hours is medium. ...TROPICAL WAVES... Please see above for a tropical wave that is moving into the eastern Caribbean with the potential for tropical cyclone development. ...MONSOON TROUGH/ITCZ... The monsoon trough exits the coast of Africa near 13N17W to low pres near 11N32W to 09N38W. The ITCZ continues from 09N38W to 11N50. Aside from convection associated to the low pressure center, scattered moderate convection is from 06N to 18N east of 18W to the coast of Africa. GULF OF MEXICO... High pressure prevails over the Gulf coast states. Gentle to moderate winds prevail north of 25N, with light to gentle winds south of 25N. Seas are in the 2-4 ft range over the NW Gulf and 1-3 ft elsewhere. For the forecast, high pressure over the southeastern U.S. will maintain gentle to moderate easterly breezes and slight seas the next few days. A cold front is forecast to reach the NE Gulf on Fri. CARIBBEAN SEA... A weak pressure gradient prevails across much of the area. Fresh to locally strong winds associated to the strong tropical wave are found over the far eastern Caribbean. Light to gentle winds prevail elsewhere. Seas are in the 4-6 ft over the far eastern Caribbean, and 1-3 ft elsewhere. For the forecast, a tropical wave over the eastern Caribbean along 62W continues to show signs of organization, and it will likely become a tropical depression within the next couple of days. The disturbance is forecast to move west-northwestward toward the central Caribbean Sea later this week. Interests in the Windward Islands should closely monitor the progress of this system as heavy rainfall and gusty winds are affecting these islands. Regardless of development, heavy rainfall is forecast to affect northwestern Venezuela, northeastern Colombia, and the ABC island chain later this week. An Air Force Reserve reconnaissance aircraft is scheduled to survey the system this evening. ATLANTIC OCEAN... Please read the SPECIAL FEATURES section above for information about Major Hurricane Fiona. Outside of Fiona, high pressure prevails across the tropical and subtropical waters east of 60W. Winds over this area are in the gentle to moderate range, with seas of 3-5 ft. South of 20N, an area of low pressure is embedded within the monsoon trough near 11N32W. Moderate winds prevail across the waters south of 20N, with seas in the 3-5 ft range. For the forecast W of 55W, Major Hurricane Fiona near 25.6N 71.5W 937 mb at 5 PM EDT moving N at 8 kt. Maximum sustained winds 115 kt gusts 140 kt. Fiona will move to 27.0N 71.0W Thu morning, 29.5N 69.6W Thu afternoon, 32.6N 66.9W Fri morning, 37.4N 63.0W Fri afternoon, become extratropical and move to 43.5N 61.1W Sat morning, and 47.0N 61.0W Sat afternoon. Fiona will weaken as an extratropical cyclone near 52.5N 60.5W Sun afternoon. Swells generated by Fiona will continue to spread westward across the southwestern Atlantic toward the northwestern Bahamas and the east coast of the United States during the next day or two. The swells could cause life-threatening surf and rip current conditions. A cold front will drop south over the north waters early on Fri through Sat night followed by fresh northeast winds and building seas. High pressure will build in behind the cold front. $$ AL/Hagen