CNN
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A major change in the United States’ weather pattern is coming, with an outbreak of Arctic air bringing a taste of winter to millions of people.
It all begins this weekend, when a cold front will allow air with December temperatures, coming from the North Pole, to begin to spread towards the north of the country. This front will move south and east over the weekend, and temperatures could drop 10 to 15 degrees Fahrenheit below normal across most of the area east of the Rocky Mountains by Sunday night.
These wintry conditions, with the lowest temperatures of the season, could reach the Gulf Coast early next week.
This brief change in the weather pattern could also activate, for the first time this season, the lake effect and cause significant snowfall in the Great Lakes area.
Here’s how this frigid weather change will play out.
Parts of the Northern Great Plains and Upper Midwest will be the first to experience a marked drop in temperatures starting Saturday. This decrease could be accompanied by winter precipitation in some areas.
In Minneapolis, a near-normal high temperature is expected on Friday, between 7 and 10 degrees Celsius, but it will barely reach 1.5 to 4 degrees Celsius on Saturday. Mixed rain and snow showers are possible throughout Saturday. Typically, the city sees its first significant snowfall — defined as at least 0.25 centimeters — before Nov. 3, but this has not yet occurred and is unlikely to happen on Saturday.
The intense cold, typical of December, will extend to much of the country on Sunday.
The day will begin with lows of -7°C or lower across much of the central United States and will remain frigid. Temperatures could be several degrees below average across much of the Great Plains, the Midwest and parts of the Ohio and Tennessee valleys.
The high temperature in Chicago will probably barely reach 4°C on Sunday. A lower temperature than usual will also be recorded in San Luis, with a maximum of around 7 °C.
Monday morning will see the lowest temperature since spring for tens of millions of people east of the Rocky Mountains. Minimum temperatures at or below 0 degrees Celsius are expected even in Texas to the south and the Appalachians to the east.
In Buffalo, New York, temperatures are expected to drop to -7°C on Monday morning and only reach 4°C in the afternoon. The normal maximum temperature for early November in the city is around 10°C.
Monday will likely be the coldest day of the winter cold snap across much of the eastern two-thirds of the United States, but the Southeast will be the epicenter of some of the coldest-than-normal temperatures.
Nashville, Tennessee, is likely to see a high of around 7°C on Monday after temperatures drop below freezing during the early morning hours.
Monday will also see a drastic drop in temperatures in Atlanta. Sunday’s high in the city is expected to be around 21°C, but on Monday temperatures will barely reach 10°C. Temperatures could drop to near freezing by Tuesday morning, which could make it the coldest morning in Atlanta since February.
Much of the east of the country will continue to experience fairly cold temperatures on Tuesday. It is likely to be the coldest day of the season for Washington and New York City. High temperatures in Washington could be around 7°C and in New York City around 4°C.
This cold snap won’t last long, however: Temperatures across much of the central United States will quickly rebound to near or even above normal levels on Tuesday, with most of the East following suit on Wednesday.
The emergence of arctic air could cause the first significant snowfall of the year in some areas, but exactly where and how much snow will fall is still being defined.
Areas that typically receive snow in the lee of the Great Lakes are, so far, the most likely to experience this phenomenon late this weekend and into next week, with the potential for lake effect after the cold front crosses the lakes on Sunday. Some snow could accumulate in Indiana, Michigan, Ohio, Pennsylvania and New York through Monday night.
There’s also a chance that the same storm that likely brought severe weather to Minneapolis at the start of the weekend could organize and become a storm that could leave a swath of snow across the Midwest early next week. While the possibility of lake effect snow seems less likely, it is worth staying vigilant in the coming days.
