000 AXNT20 KNHC 152336 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Fri Sep 16 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 2300 UTC. ...SPECIAL FEATURES... Tropical Storm Fiona is centered near 16.1N 56.1W at 15/0000 UTC or 330 nm E of the Leeward Islands moving W at 12 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 50 kt with gusts to 60 kt. Seas are currently peaking at 20 to 22 ft near and northeast of the center. Deep convection has been sheared to the east of the center that is partially exposed. Satellite imagery show numerous moderate to scattered strong convection just east and southeast of the center from 14N to 17N between 51W and 55W. On the forecast track, the center of Fiona is expected to move across the Leeward Islands Friday night and early Saturday, and move near the Virgin Islands and Puerto Rico late Saturday into Sunday. Data from an Air Force Reserve Hurricane Hunter aircraft indicate that maximum sustained winds are near 52 kt (95 km/h) with higher gusts. Little change in strength is forecast during the next few days. Fiona is expected to produce heavy rainfall that could lead to flash and urban flooding, along with isolated mudslides in higher terrains across the aforementioned locations. Considerable flood impacts are possible across eastern portions of Puerto Rico. Swells generated by Fiona are beginning to affect the Leeward Islands and will spread westward to the Virgin Islands and Puerto Rico on Friday and Saturday. These swells could cause life- threatening surf and rip current conditions. Please consult products from your local weather office. 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 T.S. Fiona NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... An eastern Atlantic tropical wave is along 20W and S of 14N moving W around 15 kt. Scattered moderate convection is ahead of the wave axis from 06N to 12N between 20W and 27W. A central Atlantic tropical wave is near 36W from 20N southward, moving W at 10 to 15 kt. A few showers are near the northern end of the wave axis. A western Caribbean tropical wave is along 82W from western Cuba southward to near western Panama, moving W around 10 kt. The wave is helping to induce scattered showers and thunderstorms over central Cuba and the Cayman Islands as well as over most of Nicaragua and NE Honduras. A diffluent pattern aloft also support this convective activity. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic Ocean through Guinea Bissau near 12N16W, passing south of the Cabo Verde Islands at 11N24W to 15N40W. Aside for the convection associated with the tropical wave along 20W, no significant convection is noted. The eastern end of the East Pacific monsoon trough is triggering scattered showers and thunderstorms over the southwestern Caribbean Sea. ...GULF OF MEXICO... A weak stationary front extends across northern Florida and the northern Gulf of Mexico. Numerous showers and thunderstorms are noted over Florida south of the front. Scattered showers and thunderstorms are along the frontal boundary over the Gulf waters. The most recent scatterometer data indicate moderate to locally fresh NE winds in the wake of the front while mainly gentle to moderate winds prevail ahead of the front. Seas are generally 1-3 ft. Winds and seas could be higher near thunderstorms. For the forecast, the stationary front will stick around for another couple of days before dissipating late in the weekend. High pressure will build over the southeast U.S. following the front, maintaining gentle to moderate easterly breezes and slight seas through early next week. ...CARIBBEAN SEA... Tropical Storm Fiona is forecast to impact the northeast Caribbean. Please refer to the Special Features Section for more details. The pressure gradient between high pressure to the N near 29N57W and Tropical Storm Fiona is creating a trade-wind surge over the NE Caribbean. Recent scatterometer data show and area of fresh to locally strong NE winds extending from the northern Leeward Islands to S of Puerto Rico near 16N68W. Scattered showers and isolated thunderstorms are within this area of winds. Similar convective activity is also noted over the central Caribbean behind the wave axis. Satellite derived wind data also show gentle to moderate trades across the remainder of the basin, with the exception of an area of fresh to locally strong winds along the wave axis over the SW Caribbean, just E of Providence and San Andres Islands. Seas are generally 3-5 ft, except 5-6 ft over the central Caribbean. For the forecast, T.S. Fiona will move to near 16.5N60W Fri afternoon, 17N64W Sat afternoon, 18N67W Sun afternoon, and 19N69W Mon afternoon. Expect increasing winds and squalls over the NE Caribbean by Fri and into the weekend. Otherwise, moderate to fresh trades will prevail over the central Caribbean through Fri. ...ATLANTIC OCEAN... Tropical Storm Fiona is forecast to impact portions of the Atlantic and northeast Caribbean. Please refer to the Special Features Section for more details. A stationary front enters the forecast area near 31N77W, and continues SW to across northern Florida. Numerous showers and thunderstorms are over Florida and the NW Bahamas south of the front. A surface trough is analyzed ahead of this front and runs from 31N75W to south-central Florida. Moderate to fresh winds and seas of 4-6 ft are in the wake of the front while mainly moderate southerly winds and seas of 3-5 ft are ahead of the front. The remainder of the Atlantic forecast waters is under the influence of a couple of high pressure systems. A surface trough is between these features extending from 31N40W to 25N53W. Convection is limited near the trough axis. Outside of Fiona, mainly gentle to moderate winds dominate the Atlantic waters with seas of 6-9 ft in northerly swell N of 20N and E of 50W. Moderate to locally fresh NE winds are N of of the Leeward Islands and Puerto Rico with seas of 5-7 ft. For the forecast west of 55W, Tropical Storm Fiona will move to near 16.5N60W Fri afternoon, 17N64W Sat afternoon, 18N67W Sun afternoon, and 19N69W Mon afternoon. Expect increasing winds, seas and squalls near the path of Fiona. A stationary front is draped off the northeast Florida coast. Expect this front to linger near this area through most of the weekend, bringing moderate NE winds north of it along with showers and thunderstorms. $$ GR