000 AXNT20 KNHC 220452 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Thu Sep 22 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 0000 UTC surface analysis and satellite imagery through 0430 UTC. ...SPECIAL FEATURES... Major Hurricane Fiona is centered near 26.6N 71.2W at 22/0300 UTC or 480 nm SW of Bermuda moving N at 9 kt. Estimated minimum central pressure is 934 mb. Maximum sustained wind speed is 115 kt with gusts to 140 kt. Numerous strong convection is within 150 nm of the center in the E semicircle and 75 nm W semicircle. Numerous moderate convection is elsewhere within 300 nm NE quadrant, 240 nm SE quadrant, 90 nm SW quadrant and 120 nm NW quadrant. A Sofar drifting buoy measured significant wave heights of 38 ft at 21/1700 UTC. NOAA buoy 41047 at 27.5N 71.5W is measuring significant wave heights of 30 ft at 22/0340 UTC. Peak seas near Fiona are currently estimated to be 42 ft. On the forecast track, the center of Fiona will pass just to the west of Bermuda tonight and approach Nova Scotia on Friday. Little change in strength is expected through early Friday. 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 39.6N 38.0W at 22/0300 UTC or 520 nm WNW of the Azores, moving ENE at 15 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 within 270 nm of the center in the NW quadrant, 30 nm SE quadrant, 60 nm SW quadrant and 180 nm NW quadrant. Please read the latest NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. An eastern Caribbean tropical wave is along 63W from 16N southward to eastern Venezuela, moving W at 15 kt. Scattered moderate convection is within 210 nm either side of the wave axis, mainly south of 12N, including near the northeast coast of Venezuela. Isolated showers are north of 12N within 150 nm of the wave axis. A distinct surface trough is noted in recent ASCAT data with this tropical wave, and fresh winds cover the eastern Caribbean east of 66W. A tropical depression is likely to form as the disturbance moves WNW across the eastern Caribbean Sea during the next day or two, and over the central Caribbean Sea this weekend. Regardless of development, locally heavy rainfall and gusty winds are likely to affect the Windward Islands through this morning, 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 during the next 48 hours. Please refer to the latest Atlantic Tropical Weather Outlook at hurricanes.gov for more details. A tropical wave is analyzed over west Africa along 15W, moving W at 10 kt. Scattered moderate and isolated strong convection is noted within 240 nm either side of the wave axis from 06N-22N. The tropical wave is forecast to move over the far eastern Atlantic waters later today. 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 the Special Features section above for a full description of the two tropical waves in the basin currently. ...MONSOON TROUGH/ITCZ... The monsoon trough exits the coast of Senegal near 14N17W to 11N23W to a 1010 mb low pressure near 10.5N 32.5W to 09N38W. The ITCZ continues from 09N38W to 10N51. Scattered moderate isolated strong convection is noted within 210 nm of the low pressure center in its NW quadrant. Scattered moderate convection is also seen to the south of the monsoon trough from 05N-09N between 20W-32W. The 1010 mb low pressure center near 10.5N 32.5W has a low chance of tropical cyclone formation during the next 48 hours as it moves slowly northwestward or northward over the tropical Atlantic. 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, a relatively weak pressure gradient across the region will support mainly light to gentle variable winds through Mon morning with locally moderate winds during this period. A tropical wave, currently over the eastern Caribbean along 63W, is likely to develop into a tropical cyclone while over the Caribbean Sea, then approach the Yucatan Channel late Mon before moving into the Gulf of Mexico by the middle of next week. In advance of this system, moderate to fresh NE winds will develop over the southern half of the basin by Mon afternoon. CARIBBEAN SEA... Please see the Special Features section above for details on the strong tropical wave over the eastern Caribbean Sea which has a high chance of developing into a tropical cyclone within the next 48 hours. Gentle winds cover most of the remainder of the basin, west of 67W. Seas are 4-7 ft east of 67W and 1-3 ft elsewhere. For the forecast, the tropical wave along 63W is likely to develop into a tropical cyclone by the time it reaches the central or western Caribbean in a few days. There is a chance it could strengthen as it approaches the Yucatan Channel late Mon. Therefore, increasing winds, seas and squalls can be expected with this system as it moves farther west in the basin. ATLANTIC OCEAN... Please read the Special Features section above for information about Major Hurricane Fiona. The area of strong winds and high seas associated with Fiona currently extends from 22N-31N between 65W-76W. Fresh SE winds extend eastward to 60W and southeastward to the Caribbean. An area of convection is noted over Hispaniola and adjacent waters from 19N-22N between 68W-74W. High pressure ridging prevails over the remainder of the basin, to the east of Fiona. Moderate trades prevail between 22W-60W with seas of 3-6 ft. Fresh winds and seas to 7 ft are near the Windward Islands due to the aforementioned tropical wave. The latest ASCAT data shows fresh to strong NE winds off the coasts of Morocco and Western Sahara, where seas are likely 5-7 ft. For the forecast W of 55W, Major Hurricane Fiona will move to near 31N69W this evening and to near 35N65W Fri morning. Swells generated by Fiona will continue to spread westward across the SW Atlantic toward the NW Bahamas and the E 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 of 31N over the north waters early on Fri through Sat night, followed by fresh northeast winds. Seas will remain high after Fiona leaves the area, due to the frontal passage. High pressure will build in behind the cold front. $$ Hagen