Around 16 million people across the Plains were potentially facing two days of powerful tornadoes starting Friday as many residents were still picking through the damage caused by an outbreak of more than 50 twisters two days ago.
The threat level was set to increase in the afternoon in parts of Oklahoma and Texas, with that area broadening into Nebraska and Kansas on Saturday, according to meteorologists.
In many areas the twisters would be accompanied by "very large hail," according to the National Weather Service.
While forecasts showed there likely would not be many tornadoes as Wednesday's outbreak, the new round was more likely to include "long-track" tornadoes — twisters that stay on the ground for prolonged periods of time and have the potential to cause major damage and injury.
"Long-track tornadoes are more severe, absolutely," Weather Channel lead meteorologist Michael Palmer said. "These are the ones that threaten the most significant damage and loss of life."
The threat came as many communities from Nebraska to Texas were still picking through their damaged homes following Wednesday's outbreak. Nine more twisters were reported on Thursday but there were no reports of significant damage, the NWS said.
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On Thursday, Weather Channel senior meteorologist Nick Wiltgen told NBC News that "the bull's eye" of the new outbreak would hit many of the same areas that had just seen damage.
On Wednesday, a 42-year-old woman drowned in an underground storm shelter as a tornado smacked Oklahoma City, one of at least 50 recorded across four states. Twelve people in an Oklahoma City trailer park were injured.
"It's worse than I expected," Mayor Mick Cornett said Thursday. "It's a relatively small and confined area, but the damage is total."
Gov. Mary Fallin declared an emergency and toured the devastation later in the day. She urged families and business to make sure they had a storm plan.
Wednesday's storms came with strong winds and large hail and also caused damage in Kansas, Nebraska and Texas. In Kansas, at least one person was hurt, and as many as 150 of cattle were killed when an apparent twister struck a feedlot.