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| #940495 (Received by flhurricane at: 10:45 PM 15.Sep.2018) TCDAT1 Tropical Storm Florence Discussion Number 67 NWS National Hurricane Center Miami FL AL062018 1100 PM EDT Sat Sep 15 2018 Florence`s center continues to trudge slowly westward across South Carolina, but heavy rainbands are still streaming inland from the ocean across extreme southeastern North Carolina. The NOS station at the Johnny Mercer Pier in Wrightsville Beach in the vicinity of these rainbands is the lone observing station that has still been reporting sustained tropical-storm-force winds, and based on the most recent observations, Florence`s maximum winds are estimated to be 35 kt. Florence is expected to weaken to a tropical depression within the next 6-12 hours, with the global model fields showing winds decreasing below 35 kt near the coast very soon. Continued weakening is anticipated while Florence moves farther inland, and it is likely to become a remnant low in about 36 hours when its circulation becomes less defined. Florence is then expected to become a strengthening extratropical low between days 3 and 5 when it exits the Northeast U.S. coast and moves out to sea. The initial motion is still very slow toward the west, or 275/3 kt. A mid-level ridge across the Upper Midwest and Great Lakes is currently blocking Florence from making much headway, but that feature is expected to slide eastward to the western Atlantic during the next 24 hours. This should allow Florence to recurve and accelerate across the Ohio Valley and the northeastern U.S. during the next 3 days, and then accelerate further toward the east-northeast over the Atlantic Ocean on days 4 and 5. The new NHC track forecast is essentially an update of the previous one and is close to the various model consensus aids. Key Messages: 1. Life-threatening, catastrophic flash floods and prolonged significant river flooding are likely over portions of the Carolinas and the southern to central Appalachians from western North Carolina into west-central Virginia and far eastern West Virginia through early next week, as Florence moves slowly inland. In addition to the flash flood and flooding threat, landslides are also possible in the higher terrain of the southern and central Appalachians across western North Carolina into southwest Virginia. 2. Tropical storm conditions will continue along the coast within the tropical storm warning area and also well inland across portions of South Carolina and North Carolina overnight. 3. Large swells affecting Bermuda, portions of the U.S. East Coast, and the northwestern and central Bahamas will continue this week, resulting in life-threatening surf and rip currents. FORECAST POSITIONS AND MAX WINDS INIT 16/0300Z 33.7N 80.5W 35 KT 40 MPH...INLAND 12H 16/1200Z 34.3N 81.6W 30 KT 35 MPH...INLAND 24H 17/0000Z 35.8N 83.2W 25 KT 30 MPH...INLAND 36H 17/1200Z 37.8N 83.2W 20 KT 25 MPH...POST-TROP/REMNT LOW 48H 18/0000Z 39.2N 81.3W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 19/0000Z 41.5N 71.5W 25 KT 30 MPH...POST-TROP/EXTRATROP 96H 20/0000Z 43.0N 59.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 120H 21/0000Z 45.5N 47.0W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Berg |
