Forecasters warn of life-threatening storms

In an unusual move, national weather forecasters have issued an early warning that conditions are ripe for violent tornadoes to rip through the Midwest this weekend.

According to a story by the Associated Press, the expected weekend storms will stretch from Texas to Minnesota and could be a "high-end, life threatening event."

On Friday, a tornado was seen near the University of Oklahoma campus in Norman just after 4 p.m. local time, according to a local television station. There were no reported injuries.

This is only the second time in history that the Storm Prediction Center issued a high-risk warning more than 24 hours in advance, Russ Schneider, director of the center told the AP.

The worst weather is expected to develop late Saturday afternoon between Oklahoma City and Salina, Kan., Other areas also could see severe storms with baseball-sized hail and winds of up to 70 mph, forecasters told the AP.

The warning issued Friday covers parts of Illinois, Iowa, Kansas, Missouri, Nebraska, Oklahoma and Texas.

The Storm Prediction Center advises residents in those areas should be aware of warnings and alerts and seek shelter in a safe place should severe weather hit.