On Thursday morning, 11 million people woke up under winter weather alerts stretching from the Sierra Mountains, across the Rockies and stretching into the Central Plains and the Upper Midwest.
The storm was expected to strengthen on Thursday, with the heaviest snow expected to fall over portions of the Central Rockies, where 1 to 2 feet of snow likely.
Denver is not expected to get big snow totals out of this, with a forecast for an inch or less. If they can get measurable snow, however, it will snap their 232-day streak of no snow.
While Denver may not be able to break their snowless streak, Salt Lake City has a good chance to do it. They are expected to see 3 to 6 inches of snow, locally higher amounts, which will break their 258-day snow drought.
In addition to the snow, wind gusts as high as 70 mph in the mountains could cause low visibility and dangerous travel conditions.
On Friday, the heavy snow will track across the southern Plains and into the Upper Midwest. For these regions, 6 to 8 inches of snow will be possible through Friday night.
By Saturday, the heaviest snow will move up into Canada, but heavy rain and isolated thunderstorms will be possible for the Mid-Atlantic, Northeast and New England. Rainfall amounts are expected to be a half an inch to 2 inches through Saturday.
While the snow and wind will create treacherous travel conditions, the most dangerous aspect of this storm system will be the southern side producing severe thunderstorms on both Friday and Saturday.
On Friday, 16 million people are at risk for tornadoes, damaging winds of 75 mph or stronger and large hail. Cities to watch include Shreveport, Louisiana, Little Rock, Arkansas, Memphis and Nashville, Tennessee, and Louisville, Kentucky.
On Saturday, the risk for strong storms shifts east to include much of the Southeast. Cities to watch will be Atlanta, Birmingham, Alabama, and Charlotte, North Carolina.
One ingredient that will fuel the severe thunderstorms and tornado risk will be the record warm temperatures in place.
After the first week of December, much of the continental U.S. is running as much as 15 degrees above average. With more record-setting warmth possible Thursday through Saturday and then another warmup middle of next week, this December could end up being one of the warmest on record.
On Thursday the core of the warmth was expected across the central and southern Plains, where temperatures could reach the 80s across Texas. Friday, the record highs will possible from the Midwest to the Gulf Coast including for cities like Springfield, Missouri, Little Rock and New Orleans.
Saturday the record warmth reaches the East Coast where cities like Washington, Philadelphia and New York could set record highs with temperatures in the mid-60s to 70 degrees.
Sunday and Monday will feature cooler temperatures nationwide before the next round of record-setting warmth arrives for the central Plains and Midwest in the middle of next week.
And all of this warmth comes on the heals of the seventh warmest November for the continental United States, and third-warmest fall.
