National Weather Service United States Department of Commerce

HEADLINE

After a brief return to chilly weather over the next two days, temperatures will once again climb above normal by the end of the week.

 

DISCUSSION

A  deep upper low currently over southern Minnesota will meander slowly northeastward into the Great Lakes over the next couple of days.  As it does, a colder airmass will be pulled into central Illinois on brisk westerly winds...resulting in high temperatures dropping into the 30s for Monday, December 30th and Tuesday, December 31st.  As a piece of energy rotates around the parent low, light snow will develop along and north of the I-74 corridor Monday night into Tuesday morning.  A minor accumulation of less than 1 inch will be possible.

Once the low lifts into eastern Canada, a flat west-to-east upper flow pattern will resume across the U.S.  This will allow temperatures to quickly climb back into the lower 50s by Thursday, January 2nd.  After that, mild weather will continue into the weekend before a cooling trend develops by early next week.  While medium range models suggest the zonal flow pattern will become more northwesterly next week, the coldest Arctic air will remain locked well to the north across northern Canada.  As a result, temperatures are expected to return to seasonal readings in the upper 30s to around 40 after Sunday, January 5th...but no bitterly cold Arctic outbreaks are anticipated. 

 

The latest 6-10 day outlooks (January 4-8) from the Climate Prediction Center (CPC) suggest near normal temperatures and below normal precipitation across central Illinois.

 

Issued: 12/29/19