The coldest air of the season so far is set to arrive later this week for the Northern Plains-Midwest and into parts of the South and East. The threat for heavy lake effect snow across the Great Lakes continues to increase as well. 

Next weather system to only brush far southern portions of the Chicago area late Wednesday before bringing rain and wet snow to the Northeast on Thanksgiving Day

Incoming arctic air over relatively warm lake waters activates the “Lake Effect” snow machine.  

Forecast animation shows the bursts of lake effect snow due later this week into the coming weekend 

Potential snowfall ahead this week 

Water temperatures still running quite mild

Forecast potential snowfall through Friday afternoon—a narrow corridor of 6″+ possible across interior sections of New England. 

Incoming chill to hit especially hard as the current Climatological Autumn period since Sept. 1 is the warmest on record at Midway Airport since records began there 96 years ago.

Tuesday’s temps the coldest morning since March 18

Tuesday morning chill marked the “first killing frost” which is a temperature of 28 degrees or colder; history shows we’re running late:  

                                                                                                                                                                                                                                                    First Killing Frost (28 Degrees or Lower)

Other cold area Tuesday morning lows 

Chicago is not alone in the late Autumn chill, many other Upper Midwest cities logged lows even colder. 

Tuesday AM Midwest lows 

Cold frontal passage ushered in some of the chilliest temperatures so far this Autumn

Tuesday mid-afternoon temperatures 

How much cooler than same period Monday?