A major winter storm and cold snap will affect nearly every state, bringing what the National Weather Service calls a “once in a generation event” that will cripple travel on some of the busiest travel days of the year.
The strengthening storm will bring more than a foot of snow and possible blizzards to the Midwest, as the weather service warns of “life-threatening” wind chills for millions.
Over 90 million people are subject to winter weather warnings and over 87 million are subject to wind chill warnings. The warnings cover 37 states and fall as far south as the Texas-Mexico border.
The number of people under winter warnings and wind chills has risen to more than 100 million people, or about a third of the US population, according to the National Weather Service.
The cold will stay through the Christmas holidays, making it the coldest Christmas in about 40 years for parts of the Plains and the Midwest.
Storm timeline:
Wednesday: The storm will strengthen across the northern plains throughout the day as heavy snowfall falls across much of the Rockies, northern plains and across the Midwest. Slippery roads will cause airport headaches and delays in 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 Services office said. While snow will fall steadily across the region, strong winds won’t kick in until Thursday.
Denver will drop from a high of 47 on Wednesday to minus 10 on Thursday at dawn. It would be the coldest day in the city 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 significantly as the front passes over the next few hours.
At sunrise the temperature is expected to be around minus 10 degrees and gusty northerly winds create a wind chill of around minus 25. Tomorrow’s high temperature is unlikely to rise above zero degrees.
A wind chill warning is in effect as well as a winter weather warning. Several centimeters of snow will also make travel difficult this afternoon through early Thursday.
Thursday: Thursday will be the hardest day to travel. The storm will hit the Midwest extremely hard with heavy snowfall and high winds. Western Minnesota will face not only blizzards but also life-threatening wind chills on Thursday and Friday.
“Whiteout conditions are expected during this period, with travel becoming very difficult, if not impossible,” the weather service said. “This event can be life threatening if you get stuck with wind chill between 30 and 45 below zero.”Chicago could also face blizzards with wind gusts of up to 50 mph, with 2 to 4 inches of snow expected.“Overall, concerns continue to grow regarding the rapid development of hazardous conditions Thursday afternoon with potentially significant impacts to the evening peak window,” the Chicago Weather Services office warned.Additionally, high winds could bring down power lines in the Midwest, especially in areas where heavy snowfall fell last week and is already weighing down tree branches. It will leave millions scrambling to find a way to stay warm when temperatures drop well below freezing.Snow could fall as far south as Jackson, Mississippi, Memphis and Nashville, Tennessee, and even Birmingham, Alabama on Thursday. Little to no accumulation is expected for most southern cities, but 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 south to northeast, as, in plus snowy roads, low visibility can make air travel dangerous.At least 1,000 flights had been canceled across the United States, according to flight tracking site Flightaware as of Wednesday evening.Chicago O’Hare International Airport leads, followed by Denver International Airport and Chicago Midway International Airport.Cancellations at these airports can have a greater impact as they are busy hubs where travelers often change planes to reach other destinations. Thursday is expected to be the busiest day before Christmas for travel.Friday: The storm is expected to become a “bomb cyclone” from Thursday evening through Friday. A bomb cyclone occurs when a storm rapidly intensifies – dropping 24 millibars (a term used to measure atmospheric pressure) in 24 hours.The storm is expected to reach the same pressure as a Category 3 hurricane by the time it hits the Great Lakes, with the weather service describing the strength of the low-level event as “once in a generation.”
“This is a case where snow totals may not tell the whole story. Even small amounts of snow, combined with very strong wind gusts and plummeting temperatures, can cause poor visibility and slippery spots on the roads. Sudden onset 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.
Blizzard warnings are in effect for parts of the Dakotas, Montana, Minnesota, Iowa, Indiana and Michigan – where travel conditions will become difficult if not impossible as the storm peaks Thursday through Friday . Major cities like Chicago, Kansas City, St Louis, 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 issues and lengthy airport delays.
Even in places where the snow has stopped, strong winds will continue to blow 30 to 40 mph across much of the Midwest and into the Northeast.
From Friday evening to Saturday morning, New England will have a quick look at snow and wind conditions.
RESOUCES CNN: