Heavy Rain/Isolated T-Storms Possible Friday Evening, Transition to Snow Likely By Saturday Morning

Rainy Afternoon:

As we've been hinting at all week long, this active stretch of weather will conclude with the strongest system of the bunch, bringing the Stateline a mixed bag of everything. A glace at the early morning surface analysis shows this upcoming storm system is still in it's developing stages as it prepares to slide off the Rocky Mountains.

It's expected to move across the Midwest, landing in the western Great Lakes by the later half of our Friday. Ahead of this storm system, the associated warm front will help bring a surge of moisture into the region by this afternoon, resulting in our first rain chances by 2-3PM. With a little instability present in our atmosphere, a few isolated thunderstorms cannot be ruled out. Severe weather is unlikely for us, but a few rumbles of thunder and lightning will be possible.

Snow Showers Saturday:

Guidance shows this potent area of low-pressure sliding into the region overnight. Strong winds on the backside of the cold front will help usher in a much cooler air-mass, cooling temperatures down into the low 30s by Saturday morning. This will help transition our overnight rain chances to wind-driven snow showers by sunrise. 

Turning our attention to the winds, the National Weather Service has placed two of our counties, Dekalb and McHenry counties, under a Wind Advisory earlier this morning. This advisory runs from 3AM to 3PM Saturday as winds (especially during the morning hours) could range anywhere from 40-50 mph. As far as snowfall accumulations are concerned, most of what we see will be confined to grassy surfaces and should be quick to melt.

Weekend Outlook:

Once this storm system makes it's way into the Great Lakes, skies will gradually clear during the afternoon with highs only peaking out in the mid to upper 30s. Similar to past cool-downs, this one will be very short-lived as a southwest breeze pushing temperatures into the mid to upper 40s by Sunday afternoon. The warmer times will continue after that as highs will peak in the low 50s both Monday and Tuesday with 60s looking more than likely for Wednesday. The bigger question at hand, will it be record warmth. As of right now, the answer is yes considering that our record high for December 15th is 58° (1971).