The uneasy calm of an unusually quiet tornado season faces disruption this weekend on the American Plains, with 32 million people in the danger zone.
Tornadoes and thunderstorms with large hail and damaging winds are likely to descend on a thousand-mile stretch from north Texas to South Dakota on Sunday, according to the National Weather Service.
Possible tornadoes were already reported in eastern North Carolina on Friday, with damage to some buildings and residences, and downed trees and power lines.
Isolated tornadoes are possible late Saturday before the system moves east through Texas, Oklahoma and Kansas on Sunday, and they could carry sustained winds of 135 mph, the weather service said.
The front will bring thunderstorms and heavy rain, which could trigger flash flooding, Weather.com warned.
The Federal Emergency Management Agency said it was monitoring the storm system and warned people across the Plains to prepare for its arrival.
The start of the 2014 tornado season has been the quietest since 1953 — thanks to lingering cold from a brutal winter — but as temperatures warm, more stormy weather is likely across the country.
This is the only recorded tornado season that hasn't been plagued by an Enhanced Fujita Scale level 3 twister, forecasters said Friday. The U.S. has so far seen zero tornado deaths — the safest start since 2002.
Still, a year after severe outbreaks struck Oklahoma, killing dozens, many schools in that state don't have the money to build tornado shelters. In rural Chickasha, four huge shipping containers are being welded together and reinforced with concrete and dirt berms.
All 225 kids at Friend School should fit inside.
"It can't be built fast enough," teacher Janet Howard told NBC News. "We're nervous every time a storm comes over."
Greg Forbes, the severe weather expert at The Weather Channel, told NBC News that the weather pattern “is beginning to get more favorable” for twisters.
Weather.com said the gusty, wet weather will progress through the Ohio Valley and South on Monday and Tuesday, though that forecast could change. A stretch from Iowa to Louisiana is at risk for tornadoes in the beginning of the workweek.