000 AXNT20 KNHC 160405 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 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 0000 UTC surface analysis and satellite imagery through 0400 UTC. ...SPECIAL FEATURES... Tropical Storm Fiona is centered near 16.0N 56.9W at 16/0300 UTC or 300 nm ESE of the Leeward Islands moving W at 13 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. A pair of recent altimeter passes confirmed seas in excess of 12 ft extend up to 270 nm from the center of the storm in the NE quadrant, 120 nm in the SE quadrant, 30 nm in the SW quadrant and 240 nm in the NW quadrant. Deep convection has been sheared to the east of the center, which is exposed. This convection has been inching closer to the center over the last several hours. Satellite imagery show numerous moderate to scattered strong convection just east and southeast of the center from 13N to 17N between 51W and 57W. 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. Environmental conditions are expected to improve, and Fiona may strengthen slightly over the next couple of days. After that time, the intensity will be highly dependent on how much the storm interacts with Puerto Rico and Hispaniola. Heavy rains from Fiona will reach the Leeward Islands Friday afternoon, spreading to the British and U.S. Virgin Islands and Puerto Rico Saturday into Sunday morning, and reaching eastern Hispaniola Sunday. This rainfall may produce considerable flood impacts including flash and urban flooding, along with mudslides in areas of higher terrain. 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 extends along 23W, from 02N to 14N, moving W at 15 kt. Scattered moderate convection is observed from 05N to 13N, between 20W and 30W. A central Atlantic tropical wave extends along 38W, from 05N to 20N, moving W at 10 kt. Isolated weak convection is observed from 15N to 21N, between 33W and 40W. Some slow development of this system is possible late this weekend and early next week when it turns northward over the central Atlantic. The current outlook assigns a low probability of tropical cyclone formation through both 48 hours and 5 days. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Mauritania near 17N16W to 12N25W to 15N38W. Associated convection in the area is described in the tropical wave section above. ...GULF OF MEXICO... A dissipating stationary boundary and surface trough in the eastern Gulf is supporting scattered moderate convection within 120 nm of the Florida coast. Similar convection is also noted along a trough in the southern Bay of Campeche. Outside of thunderstorm activity, winds are gentle to moderate from the E across the majority of the basin with 1-3 ft seas. For the forecast, a weakening stationary front from near Crystal River, Florida to 28N90W will dissipate Fri as high pressure builds over the southeastern U.S. into the weekend. This will maintain 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 gradient between subtropical high pressure and lower pressure over the southern Caribbean is supporting moderate to fresh easterly flow across the majority of the basin. Seas are 4-6 ft in the eastern and central basin and 3-5 ft in the NW Caribbean. For the forecast, Tropical Storm Fiona is near 16.0N 56.9W 1005 mb at 11 PM EDT moving W at 13 kt. Maximum sustained winds 50 kt gusts 60 kt. Fiona will move to near 16.2N 58.9W Fri morning, to near 16.5N 61.4W Fri evening, to near 16.8N 63.7W Sat morning with maximum sustained winds 55 kt gusts 65 kt, then maintain intensity as it moves to near 17.1N 65.5W Sat evening, to near 17.3N 67.0W Sun morning and to near 17.8N 68.5W Sun evening. Fiona is forecast to move inland Hispaniola near 19.5N 70.4W Mon evening, then intensify slightly as it tracks northwestward to near 21.5N 72.0W by Tue evening. Relatively weak high pressure will build behind Fiona maintaining moderate to fresh trade winds over the central Caribbean through Fri. ...ATLANTIC OCEAN... Tropical Storm Fiona is the main feature impacting portions of the Atlantic. Please refer to the Special Features Section for more details. A cold front extends across the western Atlantic from 31N76W to 29N81W. Behind the front, winds are moderate from the NE with 4-6 ft seas. Ahead of the front, winds are gentle to moderate from the SE with 2-4 ft seas. High pressure dominates the central Atlantic with light to gentle winds and 3-5 ft seas. A tighter pressure gradient in the eastern Atlantic is supporting moderate to fresh NE winds and 6-8 ft seas. For the forecast west of 55W, Tropical Storm Fiona is near 16.0N 56.9W 1005 mb at 11 PM EDT moving W at 13 kt. Maximum sustained winds 50 kt gusts 60 kt. Fiona will move to near 16.2N 58.9W Fri morning, to near 16.5N 61.4W Fri evening, to near 16.8N 63.7W Sat morning with maximum sustained winds 55 kt gusts 65 kt, then maintain intensity as it moves to near 17.1N 65.5W Sat evening, to near 17.3N 67.0W Sun morning and to near 17.8N 68.5W Sun evening. Fiona is forecast to move inland Hispaniola near 19.5N 70.4W Mon evening, then intensify slightly as it tracks northwestward to near 21.5N 72.0W by Tue evening. A cold front extending from near 31N77W to east-central Florida will stall late tonight, and linger through the weekend. Moderate to northeast winds north of the front will continue through the most of the weekend. Scattered showers and thunderstorms are expected near the front. $$ Flynn