|
Show Selection: |
| #1107395 (Received by flhurricane at: 10:48 PM 15.Sep.2022) TCDAT2 Tropical Storm Fiona Discussion Number 7 NWS National Hurricane Center Miami FL AL072022 1100 PM AST Thu Sep 15 2022 Although Fiona remains a strongly sheared tropical storm, deep convection has been inching closer to the center of circulation during the past several hours. Cloud tops remain quite cold on the system`s east side. The initial intensity is held at 50 kt based on the earlier aircraft data. Another Air Force reconnaissance aircraft is scheduled to investigate Fiona overnight. Satellite and aircraft fixes indicate that Fiona has been slowly losing latitude over the past 24 hours or so, and the initial motion is estimated to be 265/13 kt. A low- to mid-level subtropical ridge to the north of Fiona should steer the system generally westward for the next few days, taking the storm across the northern Leeward Islands Friday night and near the Virgin Islands and Puerto Rico on Saturday through early Sunday. A turn to the west-northwest and then the northwest near Hispaniola seems likely late this weekend and into early next week as the system nears a weakness in the subtropical ridge. The NHC track forecast has been adjusted to the left this cycle, based on the initial position and trending toward the latest model guidance. Fiona has been quite resilient even though it continues to be affected by westerly vertical wind shear and intrusions of dry air. The models suggest that the upper-level wind pattern could become a little more conducive for strengthening during the next couple of days, which might allow the storm to become more symmetric and strengthen slightly. However, after that time, the intensity of Fiona will become highly dependent on how much the storm interacts with Puerto Rico and Hispaniola. Since there is uncertainty on the details of the exact track, the NHC intensity forecast during the days 2-5 time frame is uncertain. This prediction lies near the middle of the guidance envelope at most forecast times. Key Messages: 1. Tropical storm conditions are expected in the Leeward Islands within the warning area by Friday evening. Tropical storm conditions are possible within the watch area across the Virgin Islands beginning on Saturday, and then reaching Puerto Rico late Saturday and Saturday night. 2. 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. 3. Fiona is expected to move near Hispaniola early next week, and watches could be required for parts of the island on Friday. FORECAST POSITIONS AND MAX WINDS INIT 16/0300Z 16.0N 56.9W 50 KT 60 MPH 12H 16/1200Z 16.2N 58.9W 50 KT 60 MPH 24H 17/0000Z 16.5N 61.4W 50 KT 60 MPH 36H 17/1200Z 16.8N 63.7W 55 KT 65 MPH 48H 18/0000Z 17.1N 65.5W 55 KT 65 MPH 60H 18/1200Z 17.3N 67.0W 55 KT 65 MPH 72H 19/0000Z 17.8N 68.5W 55 KT 65 MPH 96H 20/0000Z 19.5N 70.4W 55 KT 65 MPH...INLAND 120H 21/0000Z 21.5N 72.0W 60 KT 70 MPH $$ Forecaster Cangialosi |
