The storm that dumped snow across parts of the Rockies and northern Plains on Tuesday was expected to bring more severe weather on Wednesday.

The central and southern Plains areas were at risk for severe weather, according to the National Weather Service's Storm Prediction Center.

Swaths of land from New Mexico to Wisconsin were under winter storm warnings,while parts of Utah were under blizzard warnings.

According to the National Weather Service, Oklahoma City and Wichita Falls, Texas, were at risk for tornadoes and possible hailstorms Tuesday night and into Wednesday.

Earlier Tuesday, blizzard warnings were in effect in Colorado, where the temperature plunged more than 50 degrees in less than 24 hours and the wind chill approached zero. Wyoming got more than a foot of snow.

The culprit is a deep dip in the jet stream that swung west and pulled arctic air far into the country. As it collides with warm, moist air from the Gulf of Mexico, strong storms and tornadoes are possible in the Great Plains and Texas.

“It’s just brutal to be outside,” said Eric Fisher, a meteorologist for The Weather Channel.

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In Denver, the temperature plummeted from 71 degrees at 2 p.m. Monday to 16 degrees at 7 a.m. Tuesday, with a wind chill of 1. More than 250 flights were canceled into and out of Denver on Tuesday alone.

In Wyoming, authorities closed two stretches of interstate more than 100 miles long — I-25 between Cheyenne and Douglas and I-80 between Laramie and Rawlins. More than a foot of snow fell by midmorning in the city of Lander, and one town near the Nebraska state line reported 2-foot snow drifts.

Snow was also falling at midday Tuesday in Colorado, Utah, the Dakotas and Minnesota.

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A man crosses the street during a winter storm that brought snow and a fast plunge in temperature overnight to downtown Denver on Tuesday.

The calendar may say spring, but April is the second-snowiest month of the year in Denver. The city has averaged 9 inches in April since 1882, second only to the 11.5 inches it gets in an average March, according to the National Weather Service.

The weather pattern threatened to bring damaging wind, large hail and perhaps tornadoes to parts of Texas, Oklahoma, Nebraska and Iowa, and weaker storms later in the day in the Ohio Valley.

“We’re looking at the gamut today for severe weather,” Weather Channel meteorologist Kevin Roth said.

As the system moves east, severe storms are possible Wednesday across a boomerang-shaped swath of the country from the Texas Gulf Coast north through Indiana and into western Pennsylvania.

Severe storms could move into Georgia, West Virginia and the Carolinas on Thursday.

NBC News' Becky Bratu and The Associated Press contributed to this report.

This story was originally published on Tue Apr 9, 2013 4:59 AM EDT

Updated at 9 p.m. ET: Severe thunderstorms continued to threaten Wednesday night along a multi-state line stretching from the Southeast to as far north as the nation's capital, according to The Weather Channel.

The National Weather Service issued tornado watches across large swaths of Georgia, as well as parts of Maryland, Virginia, the District of Columbia, the Carolinas and northwest Florida, through Wednesday night. The Weather Channel warned of thunderstorms with spotty, damaging gusts and low chance of tornado in northeastern Florida and on the east side of the Florida panhandle.   

Thirteen tornadoes were confirmed to have blown through the South on Tuesday and Wednesday, according to The Weather Channel -- they touched down in Missouri, Oklahoma, Arkansas, Mississippi and Illinois on Tuesday and Indiana, Tennessee and Georgia on Wednesday.

Earlier Wednesday, a violent tornado that ripped through Adairsville, Ga., killed at least one person, overturned cars, littered Interstate 75 with debris and forced officials to shut down a 10-mile stretch of the road, officials said.

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Numerous buildings in nearby Bartow, Ga., some with people inside, were also damaged in the powerful storm, and police have received multiple calls of injuries and trauma, the Atlanta Journal-Constitution reported.

A man was killed in the state when the tornado hit his mobile home, Bartow County officials said.

Eight people went to the hospital with injuries following the storm, officials at Gordon Hospital in Calhoun, Ga., said. The storm also left at least 12,400 without power statewide, utilities providers said.

That twister was only one of a handful that touched down in the South and the Midwest Wednesday, as storms throughout the region caused widespread power outages, structural damages and were blamed for another death in the region.

The National Weather Service also confirmed another twister touched down in Sardis, Miss., heavily damaging homes in Solsberry, Ind.

Earlier, a 47-year-old man in Nashville, Tenn., was killed when a tree fell on a shed he was in, according to local fire department officials.

Meanwhile, in Monticello, Ark., a woman was struck by lightning late Tuesday but only had minor injuries, according to police, and a 32-year-old woman and a 7-year-old boy were treated for minor injuries in Marion County, Ky., the emergency management division reported.

Packing quarter-size hail and powerful winds, the storms also knocked out power to thousands of people throughout the region early Wednesday.

In Memphis, Tenn., more than 13,000 customers lost power as high winds tore down power lines and at least two tornado warnings were issued in the area, but later expired, according to the National Weather Service.

And more than 7,300 Nashville customers were without power, according to Nashville Electric. Utilities reported another 8,000 outages in Arkansas, 7,000 in Mississippi, and nearly 12,000 in Indiana.

In Arlington, Tenn., downed power lines sparked a fast-spreading grass fire that caused the evacuation of a small mental-health facility, Arlington Fire Department Lt. Chad Wiseman said.

"The wind was pushing everything really fast," Wiseman said, adding that gusts reached 50 mph as the fire was burning. "The wind feeds everything. The wind will turn a little grass fire into something that was shooting 15- or 20-foot flames in the air. It looked pretty scary."

The fire was brought under control within an hour, officials said.

A number of factors have helped build the storm system, according to meteorologists. Unseasonably warm, wet air has been pushed up from the Gulf of Mexico by southerly winds, and that is being met by cold air coming in from the Plains via Canada, The Weather Channel’s Chad Burke said, adding that the cold air is being driven eastward by unusually high winds.

"It's not a normal pattern for this time of year," said Burke. "The warm air has changed the dynamic. On the back end of the storm, you have high temperatures in the 50s and 60s in places like Chicago. By tomorrow night, they'll be at 11 (degrees)."

NBC staff writers Vignesh Ramachandran and Isolde Raftery contributed reporting.