(6:30PM - 12/17/19) Post storm wrap up regarding the recent Sun-Mon, December 15-16th Winter Storm that affected the state.
This winter storm produced widespread snow accumulation across the state, with several inches of snow for many areas. Additionally, freezing rain occurred across portions of Southern Illinois, with some ice accumulation.
This winter storm came in two waves...The first wave was Sunday morning through Sunday night, and the second wave was Monday morning through Monday night.
A large area of snow entered portions of Western and Southwest Illinois Sunday morning, eventually spreading across the heart of the state during the afternoon and evening. This period of snow continued through Sunday evening and into Sunday night, before eventually coming to an end. Much of the state received upwards of a dusting to 3" of snow, with a swath of 3-6" snow across Central Illinois. Across Southern Illinois, precipitation was a mix of rain/snow/freezing rain. Ice accumulations of a glaze to 0.10" occurred across portions of Southern Illinois.
A large area of snow entered portions of Southern Illinois mid Monday morning, eventually spreading across more of Southern and Central Illinois by late Monday morning. A period of moderate to heavy snow with 12"/hour snowfall rates occurred along the I-70 corridor, including St. Louis, for a several hour period. The snow continued in periods through Monday evening, before eventually coming to an end Monday night and early Tuesday morning. With this second wave, portions of Southern and Central Illinois received upwards of a dusting to 3" of snow, with a swath of 2-5" snow in the vicinity of the I-70 corridor. Across Southern Illinois, precipitation was a mix of rain/snow/freezing rain. Ice accumulations of a glaze to 0.20" occurred across portions of Southern Illinois.
Final storm snowfall totals across the heart of the state ranged from 3-6", with an corridor of heavier amounts of 6-9" within the main snow swath. Outside of this main swath, amounts quickly tapered to a dusting to 3" across Northern and Southern Illinois.
Below is a map representation of final snowfall totals across the state and adjacent areas, as well as our final TAM snowfall forecast from Sunday morning prior to the storm beginning. All in all the forecast was a success overall for most areas.