By Steve Olafson
OKLAHOMA CITY (Reuters) - Tornadoes touched down in Oklahoma, Nebraska and Kansas on Saturday and residents of the U.S. Plains states braced for a predicted major outbreak of dangerous nighttime twisters.
Severe thunderstorms and tornadoes were expected in the evening over parts of the three states, the National Weather Service said, and severe storms were also possible from Texas to Iowa to South Dakota and Minnesota.
"Conditions will remain favorable for strong to violent and possibly long-lived tornadoes into the overnight hours," the National Weather Service said in an advisory on Saturday afternoon.
"Tornadoes during the overnight hours can be particularly dangerous because they are usually fast-moving and obscured by rain and darkness," it added.
No deaths or injuries were immediately reported from Saturday's tornadoes by early evening. Violent twisters appeared restricted to mostly underpopulated areas.
In northwestern Oklahoma, a tornado touched down for less than a minute in the afternoon, said Rick Smith, a National Weather Service meteorologist in Norman. Tennis-ball-sized hail fell in the region, the weather service said.
A tornado also hit Mustang, a suburb of Oklahoma City, before dawn, the weather service confirmed. One home had major roof damage, and trees, power lines and fences were down, said Kristy Yager, a spokeswoman for Oklahoma City.
"We'll have storms all night long in Oklahoma," Smith said.
The pair of Oklahoma twisters hit a day after a tornado sliced across Norman on Friday afternoon.
In Kansas, a tornado touched down near Tipton in the north-central part of the state, taking tin off a building, said Mike Moritz, a meteorologist with the National Weather Service. A tornado in southwest Kansas damaged buildings on two farms in Rush County, said James Fisher, emergency management director for the county.
"We have weathered the first part of the storm," Moritz said. "We will see what happens tonight."
Tornadoes briefly touched down on Saturday afternoon in Nebraska's Nuckolls County and Thayer County, but no major damage was immediately reported, Moritz said.
Bad weather in that state led to the cancellation of Saturday's Red-White Spring Game at the University of Nebraska in Lincoln. The football scrimmage will not be rescheduled, university officials said.
"It's disappointing for the players who I know look forward to this day and it's disappointing for the fans, but what are you going to do?" Coach Bo Pelini said in a statement. "You have to look at the safety of everyone involved."
The Federal Emergency Management Agency said the worst conditions were expected to hit late on Saturday between Oklahoma City and Salina, Kansas, while other areas could see baseball-sized hail and strong winds.
Oklahoma activated its emergency operations center as a precaution ahead of the storms.
"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.
(Reporting By Corrie MacLaggan and Kevin Murphy; editing by Colleen Jenkins and Mohammad Zargham)