(2:30PM - 2/17/21) A brief recap regarding the Sun-Mon, Feb 14-16th major snowstorm that affected the state with significant snowfall accumulation for many areas.
A storm system impacted the region Sunday through Tuesday, bringing an extended period featuring waves of accumulating snow for the state. The storm system ejected out from the Gulf of Mexico and into the Southeastern US, Sunday night into Monday. The storm system then moved northeastward through the Appalachians on Tuesday. Model guidance showed the potential for this storm system several days out, includign the threat for widespread and significant accumulating snowfall to portions of the state... However, there was a late shift northwestward, which ended up bringing heavier snowfall totals to more of the state.
A lengthy period featuring two waves of accumulating snow affected the state, Sunday through Tuesday. Two distinct periods of snow impacted the state...One Sunday afternoon through Monday morning, and the second from Monday morning through Tuesday morning. The second period featured the most organized and widespread snow, in addition to the heaviest snow and most snowfall accumulation. During this entire snowstorm period (Sun morning-Tue morning) snow was of of varying intensity, with a few breaks between two periods/waves of snowfall having occurred. Snow was be moderate to heavy at times during the second period of snow, Monday morning through Tuesday morning. During this time snowfall rates of 1-2" an hour occurred at times, especially across Central, Southern and Northeast Illinois. Additionally, breezy conditions with wind gusts of 20-30MPH lead to significant blowing and drifting snow across the state, Monday and Monday night.
Additionally, lake enhancement/lake effect snow occurred across Northeast Illinois during the event from Monday morning through Tuesday morning, which significantly enhanced snowfall totals near the lake. Snowfall totals at the height of the event Monday evening were around 3" an hour.
Final snowfall totals upwards of 6-12" occurred across East-Central and Southern Illinois. Across Western, Northwest and North-Central Illinois...Totals tapered with northwest extent. Across Northeast Illinois where lake effect/enhancement occurred, snowfall totals of 9-18" occurred near Lake Michigan, with locally higher amounts around 20".
Below is a map representation of final forecasts an observed snowfall across the state and adjacent areas.