Chicago has yet to experience typical December weather. The month has started with sunshine and seasonable cool.
Expect another seasonably cold day tomorrow with sunshine giving way to increasing clouds. Those clouds will act as a harbinger of the approaching Arctic cold front and its upper level wave coming in from the west.
The cold front may not bring with it precipitation, but models are in general agreement about our first shot at a truly December-style “COLD” air mass.
The cold front passes Thursday night into early Friday morning, when we're likely to see temps in the low-to mid-20s or below. Wind chill values could make it feel like like single digits. Friday night into Saturday morning lows will drop into the teens, a few single digits not out of the question.
Here’s where a lack of snow cover makes a big difference.
Models are still unsure about when the first “measureable” snow will hit Chicago. Some say, little to no snow, others a dusting to an inch this week. Placement focus still an issue too, general consensus is along and south of I-80 by dawn Friday. Even if small amounts verify, first snow and timing may play a role in the rush hour.
Warm air advection returns for the weekend with temps gradually recovering Saturday. Still breezy, but “not as cold.” Sunday and Monday will see best return of milder air relative to the season.
If light snow fails to materialize, we will be setting the stage to break the record for the latest “measureable” snowfall for Chicago.