CNN –
A major winter storm and blast of cold will affect nearly every state, bringing what the National Weather Service is calling a “once-in-a-generation event” that will bring travel to a standstill on some of the busiest travel days in the ‘year.
The strengthening storm will bring more than a foot of snow and possible blizzard conditions to the Midwest as the weather service warns of “life-threatening” wind chills for millions.
More than 90 million people are under winter weather warnings and more than 87 million are under wind chill warnings. The alerts extend across 37 states, south to the Texas-Mexico border.
According to the National Weather Service, the number of people under winter warnings and wind chill alerts has grown to 100 million people, or about a third of the US population.
The cold will continue through the Christmas weekend, making this the coldest Christmas in approximately 40 years for parts of the Plains and Midwest.
Wednesday: The storm will strengthen across the northern plains during the day as heavy snow falls across much of the Rockies, northern plains and Midwest. Slippery roads will cause headaches and airport delays for places like Minneapolis, Omaha and Rapid City.
This system will bring 5 to 9 inches of light, fluffy snow across the region, with “the highest amounts just north and west of the Twin Cities,” the Twin Cities weather service office said. While snow will fall steadily in the region, strong winds won’t move in until Thursday.
Denver will go from a high of 47 Wednesday to minus 10 degrees by dawn Thursday. It would be the city’s coldest day in 32 years, according to the weather service. Cheyenne, Wyoming recently dropped 32 degrees in just eight minutes.
Temperatures in the Denver metro area will drop dramatically once the front passes over the next few hours.
At sunrise, the temperature is expected to be around 10 degrees below zero and gusty north winds will create a wind chill around minus 25. Tomorrow’s high temperatures are not likely to exceed zero degrees
There is a wind chill warning and a winter weather warning. Several inches of snow will also hamper travel late afternoon into early Thursday.
Thursday: Thursday will be the most difficult day to travel. The storm will hit the Midwest very hard with heavy snow and strong winds. Western Minnesota will face not only blizzard conditions, but potentially deadly wind chills Thursday and Friday.
“Whiteout conditions are expected during this time and travel becomes very difficult or impossible,” the weather service said. “This event could be life-threatening if you get stuck with wind chills between 30 and 45 below zero.”
Chicago could also face blizzard conditions with wind gusts up to 50 mph, with 2 to 4 inches of snow forecast.
“Overall, concern continues to grow for the rapid development of hazardous conditions Thursday afternoon with potentially significant impacts in the peak afternoon travel window,” the weather service office in Chicago warned.
Also, high winds can down power lines in the Midwest, especially in areas where heavy snow fell last week and is already weighing down tree branches. This will cause millions of people to find a way to stay warm as temperatures drop well below freezing.
Snow could fall as far south as Jackson, Mississippi, Memphis and Nashville in Tennessee and even Birmingham, Alabama on Thursday. Little to no accumulation is expected for most southern cities, however, Nashville could pick up about an inch of snow.
In anticipation of what will be a week of travel nightmares, United, American, Delta, Southwest and Jet Blue have issued travel waivers for dozens of airports across the country, from the South to the Northeast, because in addition of snow covering the roads, poor visibility could make air travel dangerous.
At least 1,000 flights had been canceled in the US, according to flight tracking site Flightaware by Wednesday evening.
Chicago O’Hare International Airport leads the way, followed by Denver International and Chicago Midway International.
Cancellations at these airports could have a wider impact because they are busy hubs where travelers often change planes to reach other destinations. Thursday is expected to be the busiest day for travel before Christmas.
Friday: The storm is expected to become a “bomb cyclone” Thursday evening into Friday. A bomb cyclone is when a storm rapidly intensifies and drops 24 millibars (a term used to measure atmospheric pressure) in 24 hours.
The storm is expected to reach the pressure equivalent of a Category 3 hurricane by the time it reaches the Great Lakes, with the weather service describing the strength of the landfall as a “once in a generation” event.
“This is one case where snow totals may not tell the whole story. Even small amounts of snow, when combined with very strong wind gusts and plummeting temperatures, can cause poor visibility and slippery patches on the roads. The sudden arrival of these conditions can increase the danger,” the weather service explained.
The storm will be over the Great Lakes on Friday and will continue to produce heavy snow across much of the Midwest. Parts of Michigan could pick up more than a foot of snow by Friday, making travel impossible at times.
Storm warnings are in effect for parts of the Dakotas, Montana, Minnesota, Iowa, Indiana and Michigan, where travel conditions will become difficult or impossible as the storm peaks Thursday through Friday. Major cities such as Chicago, Kansas City, St Louis, the Twin Cities and Detroit are under winter storm warnings for heavy snowfall and near blizzard conditions.
Heavy rain will also cover much of the I-95 corridor, adding to travel problems and long delays at the airport.
Even where the snow has ended, strong winds will continue to gust 30 to 40 mph across much of the Midwest and Northeast.
Friday night into Saturday morning, New England will receive a quick burst of snow and windy conditions.
Places that will escape the snow, will not escape the cold. Areas from eastern Montana to the Dakotas will experience the coldest air starting Thursday morning. Current wind chills in Montana and the Dakotas are as cold as 50 to 60 degrees below zero and will drop further after dark Wednesday.
Rapid City will feel like 45 degrees below zero Thursday morning. By Friday morning, Chicago’s wind chill will bottom out at 30 degrees below zero.
“Dangerous wind chills could cause frostbite to exposed skin in as little as 5 minutes,” the Bismarck weather service office warned.
Even the south will be dangerously cold. Wind chills in Nashville and Atlanta will drop to minus 11 Saturday morning and Birmingham will feel like minus 5.
Georgia Gov. Brian Kemp declared a state of emergency Wednesday due to impending “record low temperatures” across the state, with wind chills near zero or negative by midday Friday.
The declaration will help “ensure that essential supplies, especially propane, can be delivered for both commercial and residential needs,” the governor told reporters.
“Communities across the state are about to see temperatures they haven’t experienced in a decade or more,” Kemp said.
The state will pretreat roads and bridges in anticipation of inclement weather, and officials urged residents to avoid travel if possible.
Kentucky Gov. Andy Beshear also declared a state of emergency, with wind gusts expected to reach 40 to 50 mph on Friday and 10 to minus 26 degrees on Saturday. Beshear asked residents to stay off the roads and have a backup heat source.
Jackson and Birmingham will spend more than 80 hours below freezing between Friday and Monday. Houston could be below freezing for 46 hours between Thursday and Saturday.
Cold temperatures will continue through the Christmas weekend, before finally moderating next week.