Emerging from their holiday food comas and shuffling toward the nation's airports and highways, some Americans may discover the biggest holiday indigestion has nothing to do with pie. A potent storm is muscling into the journey home, threatening to upend post-turkey travel.
For anyone who postponed their return holiday travel to Monday or Tuesday, thinking that would make things easier, Mother Nature may have other plans.
A storm that moved through the Rockies on Friday morphed into a full-blown, cross-country storm, placing around 49 million people in the North under winter weather alerts over the weekend.
The storm is opening the door for anew, colder rushof frigid Arctic air that will send temperatures plummeting for millions right before the calendar flips to December.
Some air passengers are facing travel woes, with more than 700 US flights canceled and more than 9,400 flights delayed as of Sunday afternoon,according to FlightAware.
Those cancellations follow the more than 1,900 US flights canceled Saturday, mostly due to winter weather in the Midwest.
Many of the disruptions are in the Windy City, which has seen steady snow. More than 280 flights to and from Chicago's O'Hare International Airport were canceled as of Sunday afternoon and more than 1,300 flights were delayed, according toFlightAware. Amid a recorded 8.4 inches of snow Saturday – a new maximum snowfall record for November – the airport saw more than 1,100 flight cancellations.
As delays persisted in Chicago through midday Sunday, they increased in New York City and Boston due to a combination of low ceilings, high winds and overall holiday traveler volume.
Iowa's Des Moines International Airportresumed operationsSunday afternoon after closing when a Delta Connection flight, operated by Endeavor Air, arriving from Detroit, slid off the runway amid icy conditions on the ground Saturday night.
The flight carrying two pilots, two flight attendants and 54 passengers "left the paved surface while transitioning from the runway to the taxiway," Delta Air Lines said in a statement, confirming there were no injuries and all passengers were offered compensation.
Pre-holiday weather already proved deadly in Minnesota. A 69-year-old man was killed after being crushed by a snow-covered tree Wednesday morning amid strong winds in Alden Township, around 180 miles northeast of Minneapolis,CNN affiliate WCCOreported, citing the St. Louis County Sheriff's Office.
This post-Turkey Day storm could unleash similar dangers.
Tracking the storm
The storm pushed into the Pacific Northwest on Thursday night and moved through the Rockies on Friday.
The center of the storm moved out of the Plains early Saturday morning and strengthened throughout the day as it spread eastward through the Midwest, bringing snow, rain and even some icy mix over much of the nation's midsection.
Rain will fall on the southern side of the storm, but snow is in the forecast on the north side, which took aim at Nebraska and Kansas and northward through the Midwest. Some areas caught near the transition between mostly snow and mostly rain will deal with an icy mix for a time. Winds will also increase as the storm strengthens.
Areas east of the Mississippi River will have to deal with the storm on Sunday — snow for the Great Lakes and rain stretching through the South — while the country's midsection gets blasted by Arctic air on its backside.
The storm will move away from the East Coast late Sunday.
The wintry side
Widespread accumulating snow will stretch from the Rockies to Appalachia to close out November, and will be the first storm so far this season to accomplish the feat.
Early Saturday afternoon, Iowa State Patrol had already seen the number of vehicle crashes starting to grow and rescued close to 200 people from ditches across the state, Sgt. Alex Dinkla told CNN. "Road conditions are absolutely deteriorating very quickly," he said, noting state Department of Transportation snowplows were having a tough time keeping roads cleared.
"So if you don't have to travel, please don't, and stay home or stay with friends if you can. But if you do have to travel, we want you to take it easy," Illinois Department of Transportation Secretary Gia Biagi told CNN's Omar Jimenez on Saturday. "Move slowly and know that it's going to take us a day or two to even clean up from the storm."
In Indiana, a pileup involving 35 cars and 10 semitrucks shut down Interstate 70, an important east–west thoroughfare, for five hours near Terre Haute on Saturday afternoon, according to Indiana State Police Sgt. Matt Ames.
"There were 11 people transported off the interstate by ambulance," Ames said in an email to CNN. "No major injuries only complaint of pain."
The rainy side
Rain could also disrupt holiday travel south of the snowy areas. Rain and a few thunderstorms could produce localized flash flooding in parts of the South.
Portions of the Southeast will see rain showers Sunday from this system before it finally moves offshore late Sunday night.
This rain is less likely to cause flash flooding issues, but could cause slow-going travel for anyone driving in the area.
Early Monday, a new system will begin to take shape and strengthen over the Ark-La-Tex region, bringing more rain and snow to areas hit over the weekend. It will also bring snow to areas in the Ohio River and Tennessee Valley that didn't see any snow this weekend.
As this new system moves east, it will spread snow into the Northeast and New England. There could also be significant icing in the Appalachians – a tricky forecast that will be fine-tuned in the days to come.
Des Moines, St. Louis and Chicago are just a few of the places forecast to pick up additional snow Monday. Heavy rain is also expected for much of the Southeast and Gulf Coast regions.
There is a level 1 out of 4 risk of excessive rainfall Monday, including in Houston, New Orleans and Atlanta.
Winter air is coming
The new round of significant temperature drops started Saturday in the Rockies and Plains as Arctic air plunges into the US behind the storm. High temperatures in the teens and low 20s are likely as far south as Nebraska.
Temperatures will sink to downright frigid levels overnight into early Sunday morning. Low temperatures will be in the single digits in much of the north-central US and dip below freezing all the way into northern Texas.
Sunday's high temperatures will be 15 to 20 degrees colder than typical for much of the central US. Some parts of the Midwest could end up with highs stuck well below freezing, closer to 30 degrees colder than normal.
The cold air will expand east with overnight low temperatures at or below freezing expected in most of the Lower 48. Parts of Montana, the Dakotas and the Upper Midwest could wake up to temperatures several degrees below zero on Monday.
December marks the start of meteorological winter — which runs through February — and it will certainly feel like it well into the first week of the season. Monday and Tuesday will remain quite frigid for millions of people before temperatures start to shift back closer to normal midweek.
The upcoming Arctic blast could be a preview of more cold to come deeper into December from a disruption of thepolar vortex.
CNN Meteorologists Allison Chinchar and Gene Norman and CNN's Jennifer Feldman and Lauren Mascarenhas contributed to this report.
For more CNN news and newsletters create an account atCNN.com
