000 AXNT20 KNHC 230517 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Fri Sep 23 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 0500 UTC. ...SPECIAL FEATURES... Hurricane Fiona is centered near 31.9N 68.1W at 23/0300 UTC or 170 nm W of Bermuda moving NNE at 18 kt. Estimated minimum central pressure is 932 mb. Maximum sustained wind speed is 115 kt with gusts to 140 kt. Numerous strong convection is within 120 nm of the center in the E semicircle and 60 nm W semicircle. Scattered to numerous moderate with isolated strong convection is occurring elsewhere within 360 nm NE quadrant, 240 nm SE quadrant and 180 nm W semicircle. Seas of 12 ft or higher are occurring within 240 nm NE quadrant, 330 nm SE quadrant and 300 nm W semicircle. On the forecast track, the center of Fiona will pass just to the west of Bermuda early this morning. Fiona's center will then approach Nova Scotia late today. Swells generated by Fiona are affecting the Turks and Caicos Islands, the Bahamas, the southeastern United States coast, and Bermuda. These swells will continue to spread northwestward across the western Atlantic toward the mid-Atlantic and northeast coasts of the United States and Atlantic Canada today. These swells are likely to cause life-threatening surf and rip current conditions. Please read the latest High Seas Forecast issued by the Ocean Prediction Center at website https://ocean.weather.gov/shtml/NFDHSFAT1.php and the latest NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Tropical Storm Gaston is centered near 41.0N 31.0W at 23/0300 UTC or 180 nm NW of Faial Island in the central Azores, moving E at 10 kt. Estimated minimum central pressure is 999 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Scattered to numerous moderate convection is noted within 210 nm of the center in the NE quadrant, 150 nm SE quadrant and 120 nm NW quadrant. On the forecast track, the center of Gaston will move near or over portions of the Azores today through early Saturday. Swells generated by Gaston are expected to affect portions of the Azores through Saturday. These swells are likely to cause life- threatening surf and rip current conditions. Please read the latest High Seas Forecast issued by the Ocean Prediction Center at website https://ocean.weather.gov/shtml/NFDHSFAT1.php and the latest NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. Caribbean Low Pressure Along Tropical Wave: A Caribbean tropical wave extends its axis along 67W from SW Puerto Rico southward to southwestern Venezuela, moving W at 10 kt. A 1006 mb low pressure is analyzed along the wave near 13N67W. Numerous moderate to strong convection is noted along and within 240 nm W of the wave axis from 11N-14N between 68W-72W. Locally heavy rainfall and gusty winds are likely to affect northwestern Venezuela, the ABC island chain, and northeastern Colombia through today. Interests in Jamaica and the Cayman Islands should closely monitor the progress of this system. The low pressure is expected to become a tropical depression during the next day or two while moving WNW at 10-15 kt across the central Caribbean Sea, and the chance of tropical cyclone formation is high within the next 48 hours. Expect increasing winds, seas and squalls for the central Caribbean through the weekend, and the NW Caribbean Sun night into early next week. East Atlantic Low Pressure Along Tropical Wave: An eastern Atlantic tropical wave extends its axis along 19/20W, moving W at 10 kt. A 1007 mb low pressure is analyzed along the wave axis near 15N19.5W. Scattered moderate and isolated strong convection is noted with this system from 12N-21N between 16W-22W. A tropical depression could form by this weekend while the system moves northward at about 10 kt, parallel to the coast of west Africa. This system has a medium chance of tropical cyclone formation within the next 48 hours. ...TROPICAL WAVES... Please read the Special Features section above for information about the tropical waves. ...MONSOON TROUGH/ITCZ... The monsoon trough passes off the west coast of Africa near the border of Senegal and Mauritania near 16N16.5W to 1007 mb low pressure near 15N19.5W to 1010 mb low pressure near 10N34W to 09N39W. The ITCZ continues from 09N39W to 07N48W to 08N59W. Aside from the convection related to the tropical wave described in the section above, scattered moderate isolated strong convection is noted in the vicinity of the 1010 mb surface low, from 07N-13N between 30W-37W. Similar convection is observed from 06N-09N between 24W-30W. Farther west, scattered moderate convection is seen north of the ITCZ from 09N-16N between 49W-60W. GULF OF MEXICO... A 1013 mb surface high pressure is centered just offshore of SE Louisiana near 29N89W. This is part of a broad surface ridge that extends across the northern Gulf of Mexico. Scattered clouds containing isolated showers are present over the southwestern portion of the basin. The weather is benign elsewhere. Gentle to moderate winds prevail across the basin, moderate NE to E over the west-central Gulf, where seas are 2-4 ft. Seas of 1-3 ft prevail elsewhere. For the forecast, a relatively weak pressure gradient across the Gulf waters will support mainly gentle to locally moderate winds and slight seas through the weekend. A weak cold front will reach the NE waters later this morning, then slide east of the area and dissipate Sat. On Mon, winds and seas could begin to increase across the Yucatan Channel as a possible tropical cyclone approaches from the NW Caribbean. CARIBBEAN SEA... Please read the Special Features section above for more details about the eastern Caribbean low pressure along the tropical wave with a high chance of tropical cyclone formation within the next 48 hours. The east Pacific monsoon trough is inducing scattered moderate isolated strong convection mainly inland from the coast over NE Nicaragua, Honduras and Belize. A recent ASCAT satellite wind data pass shows that light to gentle winds prevail across the western and central Caribbean, west of 72W. Seas in this area are 1-2 ft. Fresh to near-gale force winds and seas of 5-10 ft prevail over the eastern Caribbean in association with the low pressure along the tropical wave. ATLANTIC OCEAN... Surface ridging prevails across most of the basin, north of 20N and east of 60W, anchored by a 1024 mb high pressure near 33N38W. The area of 20 kt or higher winds associated with the circulation of Major Hurricane Fiona is currently confined to the area north of 25N between 61W-74W. The area of seas 8 ft or larger covers the area north of 22N between 60W-80W. Peak seas near the center of Fiona are near 50 ft in the vicinity of 31N68W. Mostly moderate winds and 4-6 ft seas prevail across the central Atlantic between 40W-60W. Over the E Atlantic, winds are fresh with 5-7 ft seas. A line of thunderstorms about 30 nm wide extends from 25N67W to 27.5N65W. Isolated tstorms are also noted from the Straits of Florida to the NW Bahamas. For the forecast west of 55W, Major Hurricane Fiona will move to near 41N62W by this evening. All of the 34-kt and higher winds are forecast to be north of 31N by late this morning. Seas in excess of 12 ft will continue to affect waters north of 27N between 55W-68W this afternoon and tonight before subsiding to 8-11 ft on Sat. A cold front will drop south over the north waters early today through Sat night, followed by fresh northeast winds. The front will keep seas in the 8-11 ft range through tonight or early Sat north of 27N and west of 74W, despite Fiona's departure. High pressure will build in behind the cold front. $$ Hagen