Frigid week in the middle of a mild winter

COLUMBUS (WCMH) -- On Dec. 23, 2023, less than 13 percent of the lower 48 states was covered with snow, setting a record for the past two decades of data collected by NOAA's National Operational Hydrologic Remote Sensing Center.

During the past week, a series of winter storms trekked across the country, dumping multiple inches of snow, accompanied by blasts of frigid winds and subzero temperatures, and leaving more than 55 percent of the country with a snow cover.

The extreme cold and dangerous travel turned deadly, with more than 60 deaths attributed to the severe winter weather in the U.S.

The pattern change coincided with a piece of the polar vortex descending on the northwestern part of the country around Jan. 10, with successive storms following extending the leading edge of arctic air to produce wide swaths of moderate to heavy snow from the interior Pacific Northwest to the Mid-Atlantic Coast.

Central Ohio saw its first significant snowfall of the winter on Friday. Major Eastern cities from Washington to Philadelphia and New York ended a more than 700-day stretch without an inch of snow falling on any day, when 2 to 4 inches accumulated on Jan. 15, and again on Jan. 19.

Relief from the harsh chill is on the way this week, as the jet stream flattens and tilts like a giant atmospheric teeter-totter, causing the bitterly cold air that brought wind chills of -30 to -60 and lower in the northern Rockies and Upper Midwest to loosen it grip.

The last week of January will reflect a dramatic shift in the upper-level winds, so much so that virtually the entire Lower 48 states will enjoy above-normal temperatures. Rain will fall over areas that had snow cover for the first time all winter.

A period of freezing rain will precede the arrival of the mild flow from the Gulf of Mexico from the southern Plains to the upper Ohio Valley and Northeast, as stubborn cold air hangs in near the surface.

Temperatures will rebound from highs in the teens to the 50s in Ohio later this week, resuming the unseasonably mild pattern that prevailed before Jan. 13, when winter temperatures (since Dec. 1) had averaged more than 7 degrees above normal.