Imagine the arrival of a squall line; the darkening skies, sudden blast of wind, and deluge of rain.
This is how the onset of the pre-Christmas winter storm will be experienced. But instead, it will be a sudden drop in temperature and bursts of heavy snow accompanying the sudden blast of wind.
This is a dangerous winter storm. And here's why.
Commodity weather apps and traditional snowfall maps won't do it justice. Roads will go from dry and mild to snow-covered and treacherous in a matter of just a few miles or minutes. All while millions of Americans are trying to reach their holiday destination before the weekend. This is especially true for motorists heading west or north into the storm.
I will summarize the most dangerous routes to avoid, followed by a "deadline to arrival" day and time for your destination.
There won't be a lot of rain or a big warm-up ahead of this storm in most areas. Snow events in the Ozarks and lower Ohio Valley are usually a changeover event, with a gradual drop in temperature as the precipitation winds down. Instead, temperatures with this front will drop more than 20 degrees in an hour, and winds will gust over 40 mph as snow picks up rapidly. Visibilities could be less than 1/8th of a mile for several hours after the passage of the front.
Here is an example of what this will look like on a graph for Cape Girardeau, Missouri on Thursday.
The following interstate routes will most likely experience something similar when the front arrives. Suggested time of arrivals for select cities are available in the following section.
Motorists who are traveling west, northwest, or southwest along the interstates mentioned above are at much greater risk of getting stranded. That is, if you don't leave in time to BEAT the Siberia-like onslaught.
That's why I've created a map with deadlines to your destination.
Please note: If you are traveling east, which is the same motion as the storm, you will likely need to plan on arriving 4 to 6 hours sooner than displayed on the map above.
This will be the most memorable week of extreme winter weather centered around Christmas in a generation.
And it WON'T all be pretty. I'm making this claim based on the cumulative impact of cold, wind, and snow during the busy holiday travel days leading up to Christmas (Thu-Sat).
A powerful winter storm - and likely a blizzard in some areas - will mark the arrival of an arctic blast that will make holiday travel nearly impossible in some areas, and any last-minute shopping miserable for most.
This is my early call on accumulations for the primary storm system moving through the Plains and Midwest Thursday and Friday. The map does not factor in any blowing or drifting of the snow that may occur through the weekend.
If you're wondering about a white Christmas, I will post an update to the probabilities posted in this story on Tuesday. Spoiler alert: Chances are much higher across Missouri and Illinois (>80%), but a bit lower from Oklahoma to Tennessee (<30%).
The bigger story during the upcoming holiday travel period is likely to be the extremely cold air mass that follows. Subfreezing temperatures will dive as far south as the Texas Gulf Coast and the I-4 corridor across Florida.
Following the initial surge of arctic air, the combination of snow cover and a weaker front or two will keep temperatures below normal for several days following the Christmas holiday for the majority of the eastern two-thirds of the nation.
An arctic front will be plunging south through western Canada Wednesday, then across the northern and central Plains Thursday. An upper-level disturbance will ride this polar jet stream south and spawn a low-pressure system over the Mid-South.
A tightening pressure gradient, plummeting temperatures, and sufficient moisture will lead to expansive wintry precipitation, primarily in the form of snow and blowing snow from the Southern Plains to the Ohio Valley as the low moves northeast. A swath of heavy snow and near-blizzard conditions will be possible northwest of the storm track, which at this time is most likely to occur from the eastern Ozarks to the western Great Lakes Friday and Saturday.
Frigid temperatures and wind chills will catch up to the snow quickly. This will be an abnormal snow event for many cities at a more southern latitude where only marginally cold enough temperatures usually accompany the flakes. For example, the majority of snowfall in St. Louis will occur at temperatures lower than 20º. Subzero temperatures and wind chills will follow the precipitation for many days, leading to one of the coldest Christmas holidays in many years.
On the 12th day before Christmas, when all throughout the Midwest
Forecasts were teasing snow, but some say it's still a guess.
Poetic cuteness aside, significant changes are coming to the weather pattern in the next two weeks that will have many snow lovers rejoicing. Others will just be bothered by the bitter cold. Nonetheless, chances of a white Christmas are more than twice as high (compared to normal) this year from the Upper Midwest to the Southern Plains.
Confidence is high in a colder-than-normal holiday period for much of the continental United States. Credible forecast models all project below-normal temperatures for the seven days surrounding December 25 in all locations east of the Rockies. However, they do differ in the extent and magnitude of extreme cold (compared to normal) during this period, which is also likely a factor of timing.
The three images below show 7-day average temperature anomalies from multiple runs of the GFS (American), ECMWF (European), and CFS (NOAA).
Temperatures are likely to be at least 10 to 15 degrees below normal from the Northern Plains to the Mid-South on or around Christmas Day. The numbers could be a lot colder than that in some areas, depending on snow cover and the track of multiple storm systems leading up to the holiday.
Here's an example long-range forecast for St. Louis from the GFS. The red box is drawn around a projected stretch of more than a week with subfreezing temperatures (day and night). According to this model, temperatures might even not top 20º for 72 hours straight!
Details on exactly how cold, and for how long, will become more apparent in the days to come. And those specifics will be significantly related to who gets snow or not.
Chances of at least one inch of snow on the ground (or falling) on Christmas Day are more than two times as high as the 30-year average across a large area of the nation's midsection. The interactive graphic below compares the historical probability (1981-2020) to my 2022 forecast.
Cities such as Oklahoma City, Little Rock, and Nashville that historically have less than a 1 in 10 chance of a white Christmas have elevated probabilities of 20 to 30 percent this year. Chances are also more than two times as high (compared to normal) across the Ozarks and lower Ohio River Valley.
The Arctic air that has been bottled up in western Canada since Thanksgiving is about to be unleashed by the powerful storm system moving across the nation this week. It will then be driven farther south by another storm system next week (Dec 19-23), with potentially a third cold front delivering the "knock out" blow of arctic air deep into Dixie.
At this time, significant differences and inconsistencies in model solutions preclude me from posting details on when, where, and how much snow or ice may fall during the week of Christmas. I will be posting numerous times on those details as they become available, including credible modeling and road condition data from my employer Baron Weather.
But for now, just know that this year's Christmas will likely be much colder than normal (and possibly white) from Montana to Mississippi. Temperature anomalies along the west and east coasts are less certain, but an active jet stream pattern is sure to deliver bouts of cold and snow in those areas as well in the coming weeks.
Snow will be sparse this Christmas east of the Rockies and south of I-90, and confidence is high that it will be unusually warm across the Southeast.
An onslaught of winter storms is likely to blanket much of the West with feet of snow over the next 12 days, especially in higher elevations. A white Christmas is also likely across the Northern Plains, Great Lakes, and inland areas of New England from one or two winter storms prior to the 25th.
Cities where snow on Christmas Day is not that uncommon, such as Denver, Des Moines, Chicago, Pittsburgh, New York and Boston, are unlikely to see the magical morning this year. And farther south, a pre-Christmas storm may bring the potential for heavy rain or thunderstorms from the Southern Plains to the Ohio Valley.
White Christmases have become less frequent across more than half of the nation, according to the new 1991-2020 climate normals.
There is some evidence climate change may be leading to warmer Decembers across the Southeast, making snow even more rare around the holiday. But the grinch to blame for this year's brown Christmas across the Midwest is an oscillating climate pattern known as La Niña. This cooling of the equatorial Pacific waters correlates with a wavier jet stream across North America that allows warmer air to surge north more frequently from the Gulf of Mexico.
Long range teleconnection data suggests a change in the pattern may allow colder air to penetrate deeper into the center and eastern parts of the nation by early January, but above normal temperatures (overall) are likely to continue in the Southeast for much of the winter.
Bad weather will not affect most travelers on the way to their Thanksgiving destination this year.
Relatively quiet weather is expected across most of the nation, with only a few potential road bumps. If you experience a delay, it will likely be brief or possibly caused by other factors such as heavy volume.
In the Midwest and Central Plains, strong winds in the middle and lower levels of the atmosphere may result in some bumpy ascents and descents at airports such as Kansas City, St. Louis or Chicago. Showers will also be developing later in the evening and overnight hours along the Interstate 35, 44, and 55 corridors from Texas to Illinois. For most of my readers, this the only potential nuisance prior to Thanksgiving Day.
The interactive map below shows forecast wind gusts from one particular model, and is only a representation of what may happen.
The coolest air yet of the fall season has taken over the Southeast, but aside from needing a jacket for those pit stops, all roadtrips will be a "go". There will be little in the way of weather-related airline delays as well at all major hubs up and down the East Coast.
The only potential significant trouble spot this year just before Thanksgiving is in the Pacific Northwest, where an approaching storm could bring significant rain and snow to Seattle and Portland. However, much of this activity is expected to arrive overnight or during the day Thursday, after most travelers reach their destination.
I'll have an update posted on weather for your trip home or Black Friday shopping posted real soon. So please check back!