By The Associated Press and msnbc.com staff

Updated at 12:21 p.m. ET: OKLAHOMA CITY — At least three possible tornadoes hit central Oklahoma early Saturday in a prelude to what forecasters warned could be a day of “life-threatening” storms in the nation’s midsection. No injuries from Saturday were immediately reported.

Department of Emergency Management official Michelann Ooten said the possible tornadoes were reported west and north of Oklahoma City. One was spotted near Piedmont, a small town where a twister killed several people last May.

Weather Service meteorologist Kevin Brown told The Associated Press the storms were fairly weak but still damaged some homes. A tornado that touched down Friday afternoon sent 10 people to the hospital with “bumps and bruises” and ripped through southwest Normal, ripping up telephone poles, shredding trees and ripping off rooftops, according to the Oklahoman.

The most dangerous weather was expected to develop Saturday afternoon. Officials warned that a large area covering parts of Illinois, Iowa, Kansas, Missouri, Nebraska, Oklahoma and Texas were at risk.

“This could go into certainly to overnight situations, which is always of immense concerns to us,” Ooten said.

Tornado sirens sounded across Oklahoma City hours before dawn.

The worst conditions were projected for late Saturday afternoon between Oklahoma City and Salina, Kan., but other areas also could see severe storms with baseball-sized hail and winds of up to 70 mph, forecasters said.

‘Have an action plan’

Tim Ballisty, weather.com meteorologist, said in a posting on the website at 6 a.m. ET that the greatest threat for tornados was in parts of Iowa, Nebraska, Kansas and Oklahoma, including the cities of Lincoln, Omaha, Wichita and Oklahoma City, citing severe weather expert Greg Forbes.

“Dr. Forbes is forecasting at least a small tornado outbreak in the outlined region with the potential of some strong … tornadoes. Remember, 92 percent of all tornado deaths occur due to these stronger tornadoes!” Ballisty wrote.

“This is a life-threatening situation!” he wrote. “When a warning is issued, take shelter immediately!”

On Friday, Norman, Okla., home to the University of Oklahoma campus, got a preview of the potential destruction when a twister whizzed by the nation’s tornado forecasting headquarters but caused little damage.

Norman Regional Hospital and an affiliate treated 19 people for mainly “bumps and bruises,” and one patient remained hospitalized in fair condition late Friday, hospital spokeswoman Kelly Wells said.

The Storm Prediction Center, which is part of the National Weather Service, gave the sobering warning that the outbreak could be a “high-end, life-threatening event.”

Historic warning
Director Russ Schneider said it was just the second time in U.S. history that the center issued a high-risk warning more than 24 hours in advance. The first was in April 2006, when nearly 100 tornadoes tore across the southeastern U.S., killing a dozen people and damaging more than 1,000 homes in Tennessee.

It’s possible to issue earlier warnings because improvements in storm modeling and technology are letting forecasters predict storms earlier and with greater confidence, said Chris Vaccaro, a spokesman for the National Weather Service. In the past, people often have had only minutes of warning when a siren went off.

“We’re quite sure (Saturday) will be a very busy and dangerous day in terms of large tornadoes in parts of the central and southern plains,” Vaccaro said. “The ingredients are coming together.”

The strongly worded message came after the National Weather Service announced last month that it would start using terms like “mass devastation,” “unsurvivable” and “catastrophic” in warnings in an effort to get more people to take heed.

In Norman, video from television helicopters showed several buildings damaged in the city of about 100,000 about 20 miles south of Oklahoma City. The Oklahoman newspaper reported that among the businesses damaged was a custom cake shop, which lost a roof, windows and thousands of dollars’ worth of wedding and birthday cakes.

Source: usnews.msnbc.msn.com