Over the last day or so, model guidance has been trending weaker and further southeast with this system due to the lack of phasing, and that continues to be the case this afternoon. For that reason, we have continued to shift our swath of snow axis further south, taking it away from northern Illinois and the Chicago metro area and focusing it further south of the I-80 corridor. An update follows below...
Our system of interest this afternoon is crossing the Rockies and moving through Colorado and will be coming out into the plains later tonight into tomorrow morning. The track of this upper level low has shifted further south with less phasing as it moves through the Midwest, which ends up leading to a further south swath of snow across the state.
Below is a latest model animation (running from midnight tonight through Wednesday evening at 6pm) showing the evolution of this storm. As you can see, the darker blues or heaviest snow is now showing up further south across the state and more so south of the I-80 corridor. Areas south of I-80 will see periods of steady moderate snow with occasional moderate snow from tomorrow afternoon into Wednesday morning. The heaviest snowfall rates look to be from Tuesday evening into Wednesday morning, focused along and south of I-80 and into central Illinois.
Below is our latest expected snowfall totals map. Again, with the trends over the last 24 hours, this remains a tricky forecast and this map is subject to change between now and tomorrow afternoon but look for the heaviest totals to be across central Illinois instead of northern Illinois.
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