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| #1107581 (Received by flhurricane at: 5:18 AM 17.Sep.2022) TCDAT2 Tropical Storm Fiona Discussion Number 12 NWS National Hurricane Center Miami FL AL072022 500 AM AST Sat Sep 17 2022 While the center of Fiona is moving westward over the northeastern Caribbean Sea, the strongest winds and heaviest rains associated with the storm are still displaced to the east of the center by some westerly shear. Tropical storm conditions are ongoing over portions of the Leeward Islands. Earlier data from an Air Force Hurricane Hunter aircraft indicated the minimum pressure had fallen slightly to 1000 mb, but the aircraft winds on the final passes did not show signs of additional strengthening. A blend of the latest satellite intensity estimates and the earlier aircraft data support an initial intensity of 50 kt for this advisory. NOAA and Air Force Hurricane Hunter aircraft are scheduled to investigate Fiona this morning. The center of Fiona was adjusted a bit south of the previous track based on aircraft and radar data, and the initial motion is westward at 275/11 kt. A westward to west-northwestward motion is expected through Sunday, which brings the center of Fiona near or just south of the Virgin Islands and Puerto Rico and toward the eastern portion of the Dominican Republic. Although some of the track guidance shifted a bit right this cycle, the adjusted initial position resulted in little net change to the NHC track forecast with regard to Fiona`s closest approach to Puerto Rico. However, it is noted that the latest track forecast is somewhat slower than the previous one based on the latest guidance trends. After passing near or over the Dominican Republic, a northwestward and northward turn is expected next week over the southwestern Atlantic. The forecast track at days 3-5 was nudged a bit eastward based on the consensus aids. Fiona is expected to encounter slightly more favorable environmental conditions over the next 24-48 h. In particular, the westerly shear that has plagued Fiona for days is forecast to weaken, which could allow the cyclone`s structure to improve and become more vertically aligned. The latest intensity guidance is stronger than the previous cycle, and the NHC forecast has been adjusted upward during the first 36 h of the period. Fiona could be at or near hurricane force when it passes near Puerto Rico later this weekend, and a Hurricane Watch has been issued to account for this potential. If current trends continue, further increases to the intensity forecast may be necessary on future cycles. Some brief weakening is possible due to interaction with the mountainous terrain of Hispaniola, but re-strengthening seems likely once Fiona moves over the southwestern Atlantic next week. The NHC intensity forecast has been raised on days 3-5 in line with the latest consensus aids. Key Messages: 1. Tropical storm conditions will continue to affect portions of the Leeward Islands through this morning. Tropical storm conditions will reach the U.S. and British Virgin Islands this morning and spread westward across Puerto Rico later today and tonight. Fiona could be near hurricane strength as it moves near Puerto Rico late tonight and on Sunday, and a Hurricane Watch has been issued. Additional watches or warnings could be required later today for portions of the Dominican Republic. 2. Heavy rains from Fiona will spread west to British and U.S. Virgin Islands and Puerto Rico today, the Dominican Republic Sunday, and the Turks and Caicos Monday night. This rainfall is likely to produce considerable flood impacts including flash and urban flooding, along with mudslides in areas of higher terrain, particularly in Puerto Rico. 3. Fiona is forecast to strengthen after moving across Hispaniola early next week, and interests in the Turks and Caicos Islands and southeastern Bahamas should continue to monitor forecasts for the storm. FORECAST POSITIONS AND MAX WINDS INIT 17/0900Z 16.4N 63.3W 50 KT 60 MPH 12H 17/1800Z 16.7N 64.8W 55 KT 65 MPH 24H 18/0600Z 17.1N 66.3W 60 KT 70 MPH 36H 18/1800Z 17.7N 67.7W 60 KT 70 MPH 48H 19/0600Z 18.6N 68.9W 65 KT 75 MPH...INLAND 60H 19/1800Z 19.7N 69.9W 65 KT 75 MPH...OVER WATER 72H 20/0600Z 20.8N 70.6W 65 KT 75 MPH 96H 21/0600Z 23.0N 71.5W 75 KT 85 MPH 120H 22/0600Z 26.0N 71.5W 80 KT 90 MPH $$ Forecaster Reinhart |
