Cold Monday morning, but even colder Tuesday morning

It was a cold, cold start Monday morning for some across the Stateline as there was quite a range in low temperatures early this morning.

Rockford officially dropped to -15 degrees making it the 6th time this winter it's been at least -15 degrees, or colder, this season.  This has been the most since the winter season of 1983/1984.  The record was 11 times back in 1978/1979.  I'm sure many of you remember that winter!

Temperatures tonight could easily fall below the lows that were recorded this morning as high pressure moves into Northwest Illinois.  The record low temperature for tonight is -12 degrees which was set back in 1981.  Right now, the forecast low is calling for -13 degrees in the Rockford Metro, but surrounding and outlying areas could get even colder.  Just like Rochelle and Sterling did Monday morning. 

The reason for that is we'll have nearly a perfect set-up for 'radiational cooling' to take place.  This happens as the skies clear, winds go calm and there remains a fairly deep snow pack on the ground.  All the heat that had built up during the day under full sunshine will quickly be lost back into outer space.  Our likely only saving grace tonight will be the fact that the winds will be almost calm which will help out with the wind chills.  The downside is the temperature will quickly fall once the sun sets tonight.  We'll experience another subzero night Tuesday night before temperatures, both highs and lows, moderate through the middle of the week.