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| #1109840 (Received by flhurricane at: 10:53 PM 29.Sep.2022) TCDAT4 Hurricane Ian Discussion Number 30 NWS National Hurricane Center Miami FL AL092022 1100 PM EDT Thu Sep 29 2022 Ian continues to have the appearance of a hybrid tropical cyclone, having the characteristics of both an extratropical low with some frontal features, and a sheared tropical cyclone with convection well removed from the low-level center. The system is interacting with a mid- to upper-level shortwave trough just to its west, and this interaction may be contributing to slight strengthening. Based on a blend of flight-level and SFMR-observed winds, along with dropsonde measurements, from an Air Force Hurricane Hunter aircraft the current intensity has been increased a little to 70 kt for this advisory. The strongest winds are currently occuring over the northwestern quadrant of the hurricane. Southwesterly vertical wind shear is expected to remain high and the environmental air mass will stay dry until landfall. However, Ian could intensify a little more within the next 12 hours or so due to trough interaction and extraction of energy from the underlying warm Gulf Stream waters. Therefore the NHC forecast calls for slight strengthening before the system reaches the coast. This is above the available intensity model guidance. It should be emphasized that although Ian is not expected to be a classic hurricane at landfall, this does not diminish the threat it poses. Strong winds and storm surge will also extend far from the center and will begin well before the center arrives. Ian continues to move north-northeastward at about 030/9 kt. Over the next day or so, the cyclone is expected to turn northward and then north-northwestward as it moves along the eastern side of the shortwave trough. The dynamical model consensus, TVCN, has again shifted slightly eastward on this cycle. Therefore the NHC track prediction is, again, moved a little eastward from the previous official forecast. Key Messages: 1. There is a danger of life-threatening storm surge through Friday along the coasts of northeast Florida, Georgia, and South Carolina. Residents in these areas should follow any advice given by local officials. 2. Hurricane-force winds are expected across the coasts of South Carolina and southeastern North Carolina beginning early Friday, where a Hurricane Warning is in effect. Hurricane conditions are possible in North Carolina on Friday where a Hurricane Watch is in effect. Preparations should be rushed to completion. 3. Ongoing major to record river flooding will continue through next week across portions of central Florida. Considerable flooding is expected through Friday across portions of coastal and northeast South Carolina. Locally considerable flooding is possible across portions of North Carolina and southern Virginia through Friday. FORECAST POSITIONS AND MAX WINDS INIT 30/0300Z 30.2N 79.3W 70 KT 80 MPH 12H 30/1200Z 31.7N 79.1W 75 KT 85 MPH 24H 01/0000Z 34.0N 79.6W 60 KT 70 MPH...INLAND 36H 01/1200Z 36.0N 80.4W 30 KT 35 MPH...POST-TROP/EXTRATROP 48H 02/0000Z 37.5N 81.0W 20 KT 25 MPH...POST-TROP/EXTRATROP 60H 02/1200Z...DISSIPATED $$ Forecaster Pasch |
