Update on Snow Potential

There has been talk about snow possibly falling Saturday evening into Saturday night. That chance is still in the forecast. A low pressure system will move northeastward from Arkansas into Southern Indiana Saturday, and it will strengthen quite rapidly. This will allow plenty of moisture to be drawn north from the Gulf of Mexico during the day. Therefore, plenty of rain on the warm side and snow on the cold side of the system will be present. For Northern Illinois, we will have very cold air filtering into the region from Southern Canada Saturday evening behind a cold front, so we will be on the cold side of the system. Thus, any precipitation that falls in the Stateline will be snowfall.

The million dollar question is: how much snow can we expect? Well, it is still a difficult forecast because the forecast models are disagreeing on where the snow sets up. What we do know is that it will fall in a southwest to northeast fashion from South-Central Missouri into Northern Illinois and Indiana. As of now, the heaviest snow looks like it will set up from St. Louis to Bloomington/Normal to Kankakee, and up into Michigan. However, there will be lighter snowfall extending away from that axis of snow towards the Rockford region. The heavier accumulations will be east of I-39 and south of I-90. That means DeKalb County, Boone County and McHenry County will have the greatest probability of seeing snow greater than 1".

What we don't know is how far north and west the snow accumulation will extend. Some models show Rockford and much of the region receiving nothing. Meanwhile, other models--including the FutureCast model show above--show much of the region east of a Monroe to Freeport to Dixon line receiving snowfall.

So, with the models disagreeing on the exact track of the low and its associated snowfall, forecasting snowfall totals is quite difficult. Using a blend of the different models, and considering the very cold air that will be surging into the region (slightly ups the chances of snow extending further west), the map below is a good bet for now regarding totals by Sunday morning.

Again, there is high confidence that areas along and east of I-39 see snow, and possibly some accumulation. However, the confidence is considerably lower from Rockford, Rochelle, and Beloit, and points west. It would not surprise me if areas from Rockford west saw nothing. It would also not shock me to see Rockford pick up 1" of snow, if not a little more. In terms of the timing of the snow, it will likely move in during the middle of the afternoon and remain in place through the late evening hours before coming to an end.