The groundhog might have seen his shadow, but the upcoming blast of cold will have him scurrying to his burrow. Frigid air straight from the Arctic is set to the northern tier of the Lower 48 states, bringing the coldest air of the season. In some areas, the cold could persist for weeks. Temperatures some 30 degrees below average will descend over the northern Plains, Great Lakes and Midwest by this weekend, bringing widespread subzero readings and wind chills down to minus-30 in spots. The core of the cold will shift east with time, but may take until the second half of next week to arrive in the Mid-Atlantic and Northeast, and in a slightly tempered state.

The same pattern could bolster the risk of additional storms for those on the East Coast, although it’s too soon to specify the timing and location of any threats. The leading edge of cold air will surge southeast into Thursday, claiming a stake in much of the country as its icy tongue laps south. Chicago will see subzero lows by this weekend, with Sunday’s high only forecast at 7 degrees.

Monday morning's low temperatures as forecast by the National Weather Service. (MonLows)

In Minneapolis, Sunday’s high temperature could sit at minus-4, with lows as cold as minus-14 and wind chills down to 30-below.

Indications suggest the cold, which has connections to the high Arctic and Siberia, will be most potent in the northern Rockies, the central and northern Plains and parts of the Ohio Valley. The core of the frosty weather should remain west of the Appalachians through at least the middle of the month.

That means the jet stream, or a river of wind that snakes through the upper atmosphere, will be slicing through the Northeast, tracing the sharp gradient between the contrasting air masses and providing the needed dynamics to generate repeated wet or wintry storms.

There are signs that the pattern could dominate most of February, with mixed signals about what lies beyond in March. “Although below normal temperatures are favored to persist across the north-central U.S. during the last 10 days of February, the magnitude of the anomalous cold is favored to be less severe than earlier in the month at the current time,” wrote Jon Gottschalck, a meteorologist at NOAA’s Climate Prediction Center, in an email.

He noted that through the majority of the month, “subzero minimum temperatures [are] probable as far south as northern Kansas and northern Missouri.”

The Climate Prediction Center's outlook for mid-February. (NOAA/CPC)

The pattern is tied to a chain-reaction sequence that started at the North Pole in early January. A disruption of the polar vortex, a whirlpool of cold air and low pressure whirring above the Arctic, caused the icy eddy to split into two.