(11:45AM - 2/23/22) A winter storm is set to impact the region and state, this afternoon through Friday morning. This winter storm is expected to produce a swath of accumulating snow/sleet/ice across the region and state during this time.
A large majority of model guidance continues to show a consensus solution regarding this winter storm. Thus, our previous forecast is on track with little to no change needed with this update.
An initial lead wave is expected to move through the Ohio Valley this afternoon through Thursday morning, bringing with it an initial round of wintry precipitation across the southern half of the state. Furthermore, a main storm system will develop across the Southern Mississippi Valley Thursday morning, and will then track near the Ohio Valley Thursday afternoon and night, and eventually into the Mid-Atlantic by Friday morning. This storm system will bring a renewed push of wintry precipitation across the region and state, Thursday morning through Friday morning.
Wintry (Snow/Sleet/Ice) Aspect Forecast...
This Afternoon - Thursday Morning, Feb 23-24th ~ Lead Wave Event:
A lead wave is expected to move through the Ohio Valley, this afternoon through Thursday morning, with an associated area of precipitation traveling along with it. Precipitation in the form of a mix of freezing rain/sleet/snow will move into Southwestern Illinois by the middle of this afternoon. Across Southern Illinois, precipitation types from south to north will range from freezing rain to sleet to snow. This area of precipitation will continue into tonight across Southern Illinois, eventually becoming scattered with dry periods expected overnight tonight through mid Thursday morning.
Thursday Morning - Friday Morning, Feb 24-25th ~ Main Winter Storm Event:
As the main storm system moves through the region, an associated renewed push of precipitation will move across the state and region, Thursday morning through Friday morning. This renewed push of precipitation, in the form of snow/sleet/ice, will move into Western and Southwestern Illinois by mid Thursday morning. This area of precipitation will then further develop and spread across much of the state from midday Thursday through Thursday night, before ending by early Friday morning. A transition zone will set up much of this period across Central and Southern Illinois. Across this zone, precipitation types from south to north will range from rain across far Southern Illinois to freezing rain to sleet and then to snow across Central Illinois. North of this transition zone across affected areas of Northern and Central Illinois, all of the precipitation will fall as snow. Snow will vary in intensity, but will generally be light to moderate at times, with snowfall rates of 0.5"+ an hour possible at times.
In additional to the synoptic aspect to this winter storm period, conditions will be favorable for lake enhanced and lake effect snow across portions of Northeast Illinois, tonight through Friday morning. This will likely enhance snowfall totals for portions of the Chicago area near Lake Michigan.
Below are the snowfall and ice forecasts for this winter storm.
-An axis of of snow/sleet accumulation of 1-3" across Northern and Central Illinois, with locally higher amounts possible. Sleet accumulation of a dusting to 1" across Southern Illinois.
-Tree damage and power outages possible across far Southern Illinois, due to ice accumulation.
-Ice accumulations of a glaze (Up to 0.10") to 0.10-0.25" across Southern Illinois.
-Widespread travel impacts likely across much of the state.