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| #1109397 (Received by flhurricane at: 5:05 AM 28.Sep.2022) TCDAT4 Hurricane Ian Discussion Number 22 NWS National Hurricane Center Miami FL AL092022 500 AM EDT Wed Sep 28 2022 Ian completed an eyewall replacement cycle during the overnight hours, and very recent data from an Air Force Reserve Hurricane Hunter aircraft indicate that the hurricane has reached category 4 intensity. The plane reported that the central pressure has fallen to 942 mb, down about 10 mb from around midnight. The plane measured a peak 700-mb flight-level wind of 141 kt, and an SFMR wind of 109 kt. A blend of the 700-mb reduced wind and the SFMR yields an initial intensity of 120 kt. Although there is some moderate shear over the hurricane, this is not likely to affect Ian very much due to its large size. Some fluctuations in intensity are possible before the center reaches the coast later today, but Ian is expected to reach the coast as an extremely dangerous category 4 hurricane. Weakening is expected while Ian moves over the Florida peninsula. Ian has jogged a little to the left this morning, but the longer-term motion remains north-northeastward or 015 degrees at 9 kt. The hurricane should continue moving north-northeastward through Thursday between the western side of a subtropical ridge and a broad trough over the eastern United States. This motion is expected to bring the center of Ian onshore along the west coast of Florida later today, and over central Florida tonight and Thursday. A shortwave trough that is forecast to move southward toward the northwestern Gulf in about 24 to 36 hours is expected to sharpen the trough over the eastern U.S. causing Ian to turn northward along coast of northeastern Florida and Georgia Thursday night and Friday. The model envelope did not change much this cycle, and very little cross-track adjustments were needed to the official forecast. The GFS and ECWMF are noticeably slower than the remainder of the dynamical models, and the updated NHC track forecast is a little slower than the previous advisory and slightly slower than the TVCA consensus aid out of respect for those models. Key Messages: 1. Life-threatening storm surge is expected along the Florida west coast and the Lower Florida Keys where a storm surge warning is in effect, with the highest risk from Naples to the Sarasota region. Residents in these areas should listen to advice given by local officials and follow any evacuation orders for your area. 2. Hurricane-force winds are expected in the hurricane warning area in southwest and west-central Florida beginning Wednesday morning with tropical storm conditions expected overnight. Catastrophic wind damage is expected near the core of Ian when it moves onshore. 3. Heavy rainfall will spread across the Florida peninsula through Thursday and reach portions of the Southeast later this week and this weekend. Widespread, life-threatening catastrophic flooding is expected across portions of central Florida with considerable flooding in southern Florida, northern Florida, southeastern Georgia and coastal South Carolina. Widespread, prolonged major and record river flooding expected across central Florida. FORECAST POSITIONS AND MAX WINDS INIT 28/0900Z 25.6N 82.9W 120 KT 140 MPH 12H 28/1800Z 26.7N 82.4W 120 KT 140 MPH 24H 29/0600Z 27.7N 81.8W 70 KT 80 MPH...INLAND 36H 29/1800Z 28.7N 81.1W 50 KT 60 MPH...INLAND 48H 30/0600Z 29.8N 80.7W 45 KT 50 MPH...OVER WATER 60H 30/1800Z 31.6N 80.8W 45 KT 50 MPH 72H 01/0600Z 33.6N 81.4W 30 KT 35 MPH...INLAND 96H 02/0600Z 36.1N 82.1W 25 KT 30 MPH...POST-TROP/INLAND 120H 03/0600Z...DISSIPATED $$ Forecaster Brown |
