A tornado watch was issued about 4 p.m. by the National Weather Service for parts of Indiana, Kentucky and Illinois. The NWS predicts that several tornadoes are likely to form throughout the storm, with widespread tennis ball-sized hail and gusts up to 80 mph.

An incredibly dangerous day of severe thunderstorms including the potential for long-lasting, powerful tornadoes and hurricane-strength wind gusts is underway in the eastern half of the United States.

At least five people died and others were hurt after severe weather including a possible tornado swept through St. Louis, the mayor said.