04/14/2012 11:52 am ET Updated May 20, 2013

Oklahoma City Tornado 2012: Kansas, Nebraska And Oklahoma Brace For Storms

OKLAHOMA CITY, April 14 (Reuters) - Residents of Oklahoma, Nebraska and Kansas braced for a major tornado outbreak predicted for Saturday, and officials in Oklahoma City said a small twister already had touched down there.

No injuries were reported from the tornado in southwest Oklahoma City early Saturday. One home had major roof damage, and trees, power lines and fences were down, said Kristy Yager, a spokeswoman for Oklahoma City.

Severe thunderstorms and tornadoes are expected Saturday afternoon and evening over central and eastern Kansas, central and eastern Nebraska and central and north central Oklahoma, the National Weather Service said.

The weather service called it a "potentially very dangerous situation" and said severe storms are also possible from north Texas to Iowa to South Dakota and Minnesota.

"The storm environment appears to be very favorable for supercell thunderstorms capable of producing very large hail and damaging tornadoes for long paths from late afternoon until at least midnight," said an advisory from the National Weather Service. "Fast-moving tornadoes continuing after dark will heighten the risk to life and property."

Large cities that could be affected include Omaha and Lincoln in Nebraska; Topeka and Wichita in Kansas; and Oklahoma City and Tulsa, Oklahoma, the weather service said.

"Especially with it being a weekend, we really want to make sure that the public is aware that this is a serious threat and make sure that people are prepared," said Keli Cain, a spokeswoman for the Oklahoma Department of Emergency Management.

On Friday, a tornado was seen near the University of Oklahoma campus in Norman just after 4 p.m. local time - the same town that holds the National Storm Prediction Center, according to Rick Smith, a National Weather Service meteorologist.

The tornado ripped roofs from buildings, downed power lines and uprooted trees across Norman, a town of 110,000 people 20 miles (32 km) south of Oklahoma City, television images showed. City Hall was among the structures damaged, Cain said. (Reporting By Corrie MacLaggan; Editing by Colleen Jenkins and Philip Barbara)