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| #1109735 (Received by flhurricane at: 11:02 AM 29.Sep.2022) TCDAT4 Tropical Storm Ian Discussion Number 28 NWS National Hurricane Center Miami FL AL092022 1100 AM EDT Thu Sep 29 2022 The center of Ian has emerged into the western Atlantic Ocean to the north of Cape Canaveral. While satellite images show the system is becoming a hybrid cyclone, with frontal features outside of the core of Ian, the winds from multiple sources are notable. Velocity data from NWS Doppler radar indicate maximum winds of about 70-75 kt at 10,000 ft over land, and sustained winds of about 55 kt were recorded in the Daytona Beach area earlier this morning. These data support a higher initial intensity, now 60 kt for this advisory. The storm is moving northeastward at about 8 kt. Ian has stubbornly gone east of the track forecast for the past couple of days and has moved back over water faster than expected. A mid-level shortwave trough moving southward across the southern United States should turn Ian northward overnight and north-northwestward on Saturday. The official track forecast is shifted to the east, consistent with the latest consensus guidance. Ian should move over the Gulf Stream tonight and tomorrow for a longer period of time than previously anticipated, which should maintain Ian's central convection. Additionally, an increased pressure gradient on the northwestern side from a stationary front near the southeastern US, should provide a boost to the wind speeds on that side of the storm. We now expect Ian to become a hurricane again by this evening. As the system approaches South Carolina, Ian should maintain this intensity, and Hurricane Warnings have been issued for the entire coast of South Carolina. This scenario is consistent with the global and regional hurricane model guidance. It is worth noting that Ian is forecast to have atypical structure when it nears the southeastern United States, and strong winds will extend well ahead of the center, even on the northwestern side. 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 South Carolina coast beginning early Friday, where a Hurricane Warning has been issued. Hurricane conditions are possible by tonight along the coasts of northeastern Florida and Georgia, where a Hurricane Watch is in effect. Preparations should be rushed to completion since tropical-storm-force winds will begin well before the center approaches the coast. 3. Ongoing major-to-record river flooding will continue across portions of central Florida, with considerable flooding in northern Florida. Considerable flash and urban flooding is expected across coastal portions of northeast Florida through Friday. Local significant flooding in southeastern Georgia and eastern South Carolina is expected through the end of the week. FORECAST POSITIONS AND MAX WINDS INIT 29/1500Z 28.7N 80.4W 60 KT 70 MPH 12H 30/0000Z 30.0N 79.9W 65 KT 75 MPH 24H 30/1200Z 31.8N 79.8W 65 KT 75 MPH 36H 01/0000Z 34.0N 80.3W 45 KT 50 MPH...INLAND 48H 01/1200Z 35.9N 81.1W 30 KT 35 MPH...POST-TROP/EXTRATROP 60H 02/0000Z 37.0N 82.0W 15 KT 15 MPH...POST-TROP/EXTRATROP 72H 02/1200Z...DISSIPATED $$ Forecaster Blake |
