Mon-Tue, Jan 25-26th Winter Storm Update #5

(10:00PM - 1/24/20) A winter storm is expected to impact the state and region, Monday and Tuesday. This winter storm is expected to bring accumulating snow, sleet and ice to portions of the state.

Summary...
A winter storm is expected to impact the state and region on Monday and Tuesday, and is expected to bring accumulating snow, ice and sleet to portions of the state. The storm system will eject out into the Plains tonight and Monday, then moving eastward and eventually into the Great Lakes on Tuesday as it slowly shears out and weakens...as it encounters blocking to the northeast. Model guidance continues to attempt to hone in on a general outcome for this event, though some disagreement and changes continue to exist t this time. The track of the storm system and general location of the snowfall/ice corridors finally appears to be in place. However, as was mentioned in our update earlier today, there has been a drying trend in model guidance over the past 24 hours. We first reflected this in our midday update today by trending down expected snowfall totals a bit, and have done so again with this update as the drying trend in model guidance has continued.

Forecast...
Northern Illinois: 
Snow is expected to spread across Northern Illinois Monday afternoon and evening. Snow of varying intensity will then continue through Tuesday afternoon, except in Northeast Illinois where periods of lake effect snow will continue into Wednesday. The most significant period of snow will be from late Monday afternoon or evening through early Tuesday morning. During this time periods of moderate to even heavy snow will be possible, with snowfall rates in excess of 1" an hour possible at times. In addition to the snow, wind gusts of 30-40MPH will be possible, Monday afternoon through Tuesday morning. The combination of the snow and wind will lead to very low visibility and blowing/drifting snow at times, especially out towards the Quad Cities and the IL/IA border area.

As hinted at in the above paragraph, lake effect snow was mentioned for Northeast Illinois. It is likely that that lake enhanced snow will be seen during the storm, from Monday afternoon through Tuesday afternoon...After which time periods of pure lake effect will be possible from Tuesday afternoon into Wednesday morning.

Central Illinois...
Precipitation will spread across Central Illinois Monday morning, then continuing in periods through Tuesday morning. South of I-72 will generally see rain for the duration of the storm, though a mix is possible at times. Along and north of I-72 will see a mix of snow/sleet/freezing rain/rain, though freezing rain is expected to dominate in a corridor across Central Illinois.

Southern Illinois...
Rain will spread into Southern Illinois later tonight, and will then continue in periods through Monday night. Isolated t'storms will be possible at times. Rainfall totals in excess of 1.00" are expected across far Southern Illinois.

What's expected...
A swath of heavy snowfall totals of 5-9" is expected across Northern Illinois, with isolated higher amounts possible. There will be a sharp gradient where snowfall totals rapidly taper across across Western Illinois and along I-80 in Northern Illinois. Ice accumulation upwards of a glaze to 0.15" is expected in an axis across Central Illinois.

​Below are the snow and ice forecasts for this event.

JP