Central Florida is likely to begin experiencing tropical storm force winds by 2 p.m. today, according to the National Hurricane Center.
Heavy rains are expected throughout the storm and could cause flooding.
In Central Florida, the storm will impact Polk County first. Emergency managers there say the National Weather Service predicts one to two feet of rain over the next 36 hours.
The center of Ian is forecast to cross over Kissimmee Thursday morning.
At 2 p.m. Thursday, it will likely be over Seminole County as a tropical storm packing 60 mph winds.
And Thursday evening the storm track shows it leaving Florida at Daytona Beach.
As Ian passes through Central Florida, Polk County can expect winds of 65-85 mph with gusts up to 105, according to NWS advisories.
Lake County is forecast for sustained winds of 45 to 55 mph, with gusts up to 80. And Osceola, Orange and Seminole counties can expect winds in the range of 55-70 mph and higher gusts.