Good afternoon, Illinois residents. Our first significant winter storm of the upcoming winter season is about to get underway. Watches have been upgraded to Advisories and Warnings (see graphic below) in advance of the wintry precipitation.
'Overall, not much has changed from yesterdays forecast. Trends have shown a slight shift west with the storm center track, and much of the model guidance has shifted the snow potential a little further north and west than compared to yesterday.
Forecast amounts haven't changed much, with 4-6" expected across areas that are in a winter storm WARNING. Locally higher amounts are possible in these areas depending on the strength of any convective snow bands.
The below model plot, taken from the hi-res NAM shows the precip potentially reaching further north and west than we saw yesterday, and trends seem to support this. This will not occur until Thursday morning however, when the storm is in a weakening phase. We are not expecting any serious accumulations across northern Illinois but some areas could see an ill-timed inch of snow during the morning commute, just enough to create some road hazards, so be prepared for that.
Our latest TAM has been adjusted to reflect these new developments. We should see a healthy 3-6" swath of snow across much of central and southern Illinois. The areas that should see the most snow will Southwest Illinois, near the St Louis area. These are the areas that are currently under winter storm warnings.
While far from the worst snowstorm we've dealt with across this region. The early timing and location makes it somewhat unusual given the strength and amounts forecast. Safe travels everyone!