Lower 48 braces for bitter arctic blast in coming days; Chicago temps to dive 47-deg between late Wednesday and Saturday morning; 70+-deg pullbacks target the Plains

It’s impact won’t be felt in Chicago until Wednesday night. But, the season’s strongest push of cold air is on the move to the city’s west.

A frigid blast of arctic air continues its southward plunge through the Rockies and Plains Tuesday and Tuesday night. The system is to send temperatures crashing in coming days across the nation’s mid-section and West with readings in sections of Montana, the Dakotas, Colorado and Nebraska likely to see four-day temp drops locally exceeding 70-degrees between Tuesday and midday Friday.

Chicago, which has a surge of comparative “warmth” on the way Wednesday before the frigid air hits, could see readings drop more than 45-degrees between Wednesday afternoon and Saturday morning. In just that period period, it wouldn’t be surprising to see temps stage a dramatic pullback from Wednesday afternoon’s predicted 58-degree high—a reading nearly 20-degrees above normal— to a 7-degree morning low in parts of the area by Saturday morning.

Incoming cold spawns 1-2+ ft. mountain snows from Montana into Wyoming; Upper Midwesteners shoveling snow too!

The cold surge had dropped temps in sections of Montana into single digits late Monday and lows may be headed as low as 20 to 30-degrees below zero in the nights to come there.

The arctic blast has produced snowfalls of as much as 12 to 25” in the mountains from Montana south into Idaho and Wyoming.  And the potential for accumulating snow in the Upper Midwest, particularly northern Minnesota, has prompted winter storm warnings.

Mild, moist surge of Gulf air ahead of the coming temp crash sets stage for fog, drizzle and light rain

As temps dive to the west, a northward surge of unseasonably mild air is to send Chicago readings surging well into the 50s Wednesday ahead of the arctic blast’s arrival here.

A slight easterly component to Tuesday’s south winds means readings are likely to hold to the 40s on the Lake Michigan shoreline before more southerly winds spread into those areas Tuesday night.

The incoming mild air is to grow moist leading to widespread Tuesday and Tuesday night fog, punctuated with drizzle and spells of light rain before strengthening southerly winds thin the fog to haze by Wednesday.

Southwest upper winds over cold air mass to deliver light snow Thursday and a potentially snowier system later this weekend

Chilly as temperatures will be later this week and into the weekend, the  strongest push of cold air may await development of a snowpack here—something which may occur toward Sunday and/or Sunday night as a disturbance lifts from Colorado and the Texas Panhandle into the Midwest. It’s the type of system which could have the potential for producing enough snow to cover the ground.

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