“Brief squalls of heavy snow, strong gusty winds, and rapidly dropping temperatures will likely cause sudden whiteouts, sudden frost, and icy roads,” the National Weather Service wrote. “Even in areas not affected by snow, dangerous cold is expected.”
Nearly 70 million people are under a winter storm watch or warning in the Midwest, Great Lakes and Appalachia, and blizzard warnings were recently lifted in Minnesota.
Snow and high winds could affect major airport hubs, including Chicago O’Hare International Airport and Detroit Metropolitan Wayne County airports. The combination of snow and winds in excess of 40 mph will bring blowing snow and blowing snow that will reduce visibility to near zero at times, especially in an area from western Kansas and Nebraska north to ‘in Minnesota stretching east through western New York.
“Whiteout conditions are expected … travel becoming very difficult, if not impossible,” wrote the National Weather Service in Minneapolis. “This event could be life-threatening if you get stuck.”
Cities that could face blizzard conditions between Thursday and Friday — at least for a short time — include Kansas City, Mo., St. Louis, Des Moines, Minneapolis, Milwaukee, Chicago, Indianapolis, Detroit and Buffalo.
In some places near the Great Lakes, including Buffalo, wind gusts could reach 50 to 65 mph, causing extensive tree damage and power outages in dangerously low temperatures.
Eastward Rocky Mountain locations that avoid snowfall will not escape record cold temperatures of around 40 degrees or more below normal. Wind chill watches, advisories and warnings affect an estimated 90 million people, stretching from the Canadian border to Texas and as far east as Tennessee, with below-freezing temperatures likely to dip as low as to the Gulf of Mexico. In some places, temperatures will be the lowest in decades during the month of December.
Over the north-central United States, actual air temperatures of minus 20 to minus 40 are expected, and wind chills could flirt with minus 60. The National Weather Service in Bismarck, ND, calls the cold of “deadly”.
“Dangerously cold wind chills could cause frostbite on exposed skin in as little as 5 minutes,” he wrote.
That cold will hit the East Coast on Friday, arriving abruptly in the form of a flash freeze that could drop temperatures by 25 degrees or more in just hours. After a morning of heavy rain and perhaps a short flurry of snow, the flash freeze can turn some roads into treacherous patches of ice, potentially leading to extremely dangerous travel on major arteries such as highways 95, 84 and 81.
In the northeast, the same storm system – which will intensify so quickly that it will be called a weather “bombshell” – will push water against the coastline, causing coastal flooding.
An upper disturbance, characterized by a pocket of high altitude cold air, low pressure and rotation, will dip out of British Columbia and Alberta over the Central Plains on Wednesday and Thursday. It will explosively strengthen an area of surface low pressure pushing across the plains, turning it into a powerful storm system that will sweep across the Ohio Valley. By Friday evening, it will cross Quebec and Ontario en route to Hudson Bay.
The storm will quickly intensify into a bomb cyclone, a designation given to the most intense mid-latitude weather systems. Its pressure will drop from 1003 millibars Thursday night near the Indiana-Ohio border to 968 millibars Friday night — the approximate pressure of a Category 2 or 3 hurricane — over southern Quebec. Mid-latitude storms that drop in pressure by 24 millibars in 24 hours are considered weather bombs – that storm’s pressure is expected to drop 35 millibars in that time. The lower the pressure, the stronger the storm.
Since low-pressure systems spin counter-clockwise, the system will draw in a mild tongue of air on its east side. This will keep most of the Mid Atlantic and Northeast mostly in rain. The exception will be in Appalachia, especially the Alleghenies of western Maryland, western Virginia, and eastern West Virginia, where the entrenched cold air in the mountains will be difficult to clear. .
The National Weather Service warns of 4 to 7 inches of snow east of the Allegheny Front, in addition to a quarter inch of ice from freezing rain. This will happen in the first half on Thursday. It’s just the storm’s first round before flash freezes arrive on Friday — not just for the mountains, but also for areas toward the coastal plain — including Washington and Baltimore.
A major blizzard on the plains and the great lakes
Farther west, however, the Plains, the Upper Midwest and even parts of the Mid-South, perhaps as far south as Nashville, will see snow — and for some, lots of it. The jackpot, which could be a foot or more, appears to fall in Michigan’s Upper Peninsula, with a secondary maximum downwind of Lakes Erie and Ontario.
Even in areas that only see a few inches of snow, travel is expected to be extremely hazardous due to high winds that will limit visibility.
St. Louis, Kansas City, Omaha and the Twin Cities are under winter storm warnings, with a general 2 to 6 inches of snow likely to fall — less south, more north. West of Minneapolis, a blizzard warning is in effect; The combination of 40 to 50 mph winds and moderate to heavy snow could create whiteout conditions at the height of the storm Thursday evening through Friday, while wind and cold weather could bring wind chills below to minus- 30.
In Chicago, Detroit and Indianapolis, a winter storm watch is in effect. This is where there is less confidence in how much snow will fall. In the Windy City, the totals will likely range between 3 and 6 inches, but tread a steep incline; The accumulation will climb rapidly as one drifts towards Michigan, with a foot or more likely falling in parts of the mitt.
In the storm’s wake, cold air blowing from the west-northwest across lakes Erie and Ontario could produce lake-effect snow, although this is not a typical wind direction for the extreme accumulations, as it does not blow lengthwise over the lakes. Instead, around a foot is likely over the weekend, though meteorologists are still fine-tuning details.
“Holiday weekend travel, including Fridays, can at times be very difficult, if not impossible” through Monday, the Buffalo Weather Department wrote.
Behind the storm, a plume of Siberian air will be deflected south toward the United States, lasting approximately 72 hours and affecting nearly everyone east of the Rocky Mountains. It will first cross the Canadian border early Wednesday, blowing south as a cold front that will drop temperatures by 40 degrees or more in just under six hours.
Biting cold will sweep through Denver on Wednesday evening, sending temperatures plummeting from 40 degrees to zero in just a few hours. By Thursday morning it will be near minus-10 with wind chills around minus-30.
“Life-threatening cold arrives late Wednesday” tweeted the weather service office serving Denver. We promise this is not an exaggeration. It will likely be the coldest day in Denver’s 32 years, so many people haven’t experienced a cold snap like this.
Over the Dakotas, temperatures could drop to near minus 30 Friday evening. In Bismarck, they have been below zero since Sunday, and will remain so until Christmas. Wind chills of minus 40 are likely. Breaking down in a vehicle without an emergency kit on hand can very quickly become fatal.
This cold will dip south, arriving in St. Louis on Thursday. Highs will peak in the mid 30s with snow falling rapidly to around 3 minus overnight. Friday will not climb above the single digits.
In Oklahoma City on Thursday it won’t be more than 11 or 12 degrees. In the Texas Panhandle, temperatures could drop nearly 50 degrees into the teens on Wednesday at midnight. Locally, these fronts are known as “blue norths”.
The cold will blow all the way to the Gulf Coast by Thursday afternoon, turning the ocean into a seemingly steaming lagoon. This will be due to “Arctic Sea Smoke,” or a unique type of fog that forms when freezing air blows over warmer waters.
Flash freeze in the eastern United States
The cold will reach the East Coast on Friday, but will do so abruptly. This will pose a hazard to those driving on highways in the region, especially between Washington, DC, and Hartford, Connecticut.
Friday morning temperatures will be between 40 and near 50, with rain likely to fall as moisture swirls around in the parent low pressure system to the northwest. As the cold front passes around midday, readings will drop into the 20s, with temperature drops of 25 degrees or more likely within a three-hour window. At the same time, a very brief period of snowfall is possible.
Crews won’t be able to pre-treat the roads because of the rain, and any lingering wetness and puddles could quickly turn to ice. This could leave the roads very dangerous. Chances are that strong winds will help dry out the roads before they freeze over, but pockets of dangerous travel are a risk.
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