March 29 (Reuters) - A powerful storm in Florida forced the delay of the St. Petersburg Grand Prix car race and the evacuation of spectators from the grandstands on Saturday, said organizers who were working on a revised schedule of the three-day IndyCar event.
"When the weather lets up, we will begin letting people in through the gates. Right now we are still in evacuation procedures," the organizers of the Firestone Grand Prix of St. Petersburg said in a statement.
Florida, from the Panhandle region to Miami, was expected to be lashed by powerful storms "producing damaging winds, hail, and a few isolated tornadoes," throughout the day, the National Weather Service said in an alert Saturday afternoon.
A tornado warning was issued for parts of Orlando, about 84 miles (135 km) northeast of St. Petersburg, after meteorologists detected a twister in the area, the weather service said.
"Heavy rainfall may obscure the tornado. Take cover now," the warning said.
The storm was expected to drench areas as far south as Miami and as far north as Raleigh, North Carolina, according to AccuWeather meteorologist Brian Lada. (Reporting by Victoria Cavaliere; Editing by Cynthia Johnston and Paul Simao)