(11:45AM - 1/24/20) A major winter storm is expected to impact the state and region, Monday and Tuesday. This winter storm is expected to bring significant snowfall accumulation, as well as some ice and sleet accumulation, to portions of the state.

Summary...
A major winter storm is expected to impact the state and region on Monday and Tuesday, and is expected to bring significant snowfall accumulation, as well as some ice and sleet accumulation, 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 has been showing the potential for this winter storm for days. There was at first significant disagreement, which has waned over time...However, there is still some disagreement that continues at this time. Additionally, there has been a slight drying trend on model guidance over the past 12 hours, which would suggest slightly lower snow/ice totals than previously expected. Because of this, we have slightly cut back on totals in some areas given this continued trend.

Forecast...
Northern Illinois: 
Snow is expected to spread across Northern Illinois Monday afternoon. Snow of varying intensity will then continue through Tuesday evening, except in Northeast Illinois where periods of lake effect snow will continue into Tuesday night. The most significant period of snow will be from late Monday afternoon through early Tuesday morning. During this time periods of heavy snow will be possible, with high 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 near blizzard conditions 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 evening...After which time periods of pure lake effect will be possible from Tuesday afternoon into Tuesday night or Wednesday morning.

Central Illinois...
Precipitation will spread across Central Illinois Monday morning, then continuing into Tuesday. 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 Tuesday morning. Isolated t'storms will be possible at times. Rainfall totals in excess of 1.00" are expected across Southern Illinois.

​What's expected...
A swath of heavy snowfall totals of 6-12" is expected across Northern Illinois, with higher amounts possible near the IL/IA and further west. 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 0.10-0.25" is expected in an axis across Central Illinois.

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

JP

(10:00PM - 1/23/20) A major winter storm is expected to impact the state and region, Monday and Tuesday. This winter storm is expected to bring significant snowfall accumulation, as well as some ice and sleet accumulation, to portions of the state.

Summary...
A major winter storm is expected to impact the state and region on Monday and Tuesday, and is expected to bring significant snowfall accumulation, as well as some ice and sleet accumulation, to portions of the state. The storm system will eject out into the Plains Sunday night and Monday, moving northeastward, and eventually into the Great Lakes on Tuesday as it slowly shears out and weakens as it encounters blocking to the northeast. Model guidance has been showing the potential for this winter storm for days, though there was a high amount of disagreement regarding the overall potential. As time has gone on over the past day or so, model guidance has come into much better agreement, with a decent consensus forming.

Forecast...
Northern Illinois: 
Snow is expected to spread across Northern Illinois Monday morning. Snow of varying intensity will then continue through early Tuesday night. The most significant period of snow will be from late Monday afternoon through mid Tuesday morning. During this time periods of heavy snow will be possible, with high snowfall rates in excess of 1" an hour likely at times. In addition to the snow, wind gusts of 35-45MPH will be possible, Monday evening through Tuesday morning. The combination of the snow and wind will lead to near blizzard conditions at times, especially out towards the Quad Cities and IL/IA border area. In addition to the snow associated with the storm system, lake enhanced and lake effect snow will be possible across Northeast Illinois, from Monday evening through Tuesday night.

Central Illinois...
Precipitation will spread across Central Illinois later Sunday night and Monday 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 generally see freezing rain and sleet for the duration of the storm.

Southern Illinois...
Rain will spread into Southern Illinois Sunday night, and will then continue in periods through Tuesday morning. Isolated t'storms will be possible at times. Rainfall totals in excess of 1.00" is expected across Southern Illinois.

​What's expected...
A swath of heavy snowfall totals of 6-12" is expected across Northern Illinois, with higher amounts possible near the IL/IA and further west. 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 0.10-0.25" is expected in an axis across Central Illinois.

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

JP

(9:00PM - 1/23/21) A disturbance moving through the region today into Sunday will bring a minor/nuisance accumulating snowfall to portions of the state.

​Summary...
A disturbance will be moving through the region, today into Sunday. This disturbance and associated warm air advection will lead to periods of snow across Northern Illinois, early tonight through early Sunday afternoon. Model guidance has been and continues to be in good agreement regarding this event, and observational trends have been supportive, thus little to no change is needed with this update.

Forecast...
​Areas of snow and snow showers across the Midwest have been pushing eastward through the day today. This activity will first enter Northwest Illinois early tonight, steadily spreading across the rest of Northern Illinois overnight tonight. This activity will then continue in periods across Northern Illinois, through mid to late Sunday morning.

​What's Expected...
Final snowfall totals upwards of a dusting to 1" or so are expected across Northern Illinois and portions of Central Illinois, with upwards of 1-3" possible across far Northern and Northwest Illinois.

​Below is the snowfall forecast for this event.

JP

(11:45AM - 1/23/20) A major winter storm is expected to impact the state and region, Monday and Tuesday. This winter storm is expected to bring significant snowfall accumulation, as well as some ice and sleet accumulation, to portions of the state.

Summary...
A major winter storm is expected to impact the state and region on Monday and Tuesday, and is expected to bring significant snowfall accumulation, as well as some ice and sleet accumulation, to portions of the state. The storm system will eject out into the Plains Sunday night and Monday, moving northeastward, and eventually into the Great Lakes on Tuesday as it slowly shears out and weakens. Model guidance has been showing the potential for this winter storm for days, though there was a high amount of disagreement regarding the overall potential. As time has gone on over the past day or so, model guidance has come into much better agreement, with a loose consensus forming.

Forecast...
Northern Illinois: 
Snow is expected to spread across Northern Illinois Monday morning. Snow of varying intensity will then continue through early Tuesday night. The most significant period of snow will be from late Monday afternoon through mid Tuesday morning. During this time periods of heavy snow will be possible, with high snowfall rates in excess of 1" an hour likely at times. In addition to the snow, wind gusts of 35-45MPH will be possible, Monday evening through Tuesday morning. The combination of the snow and wind will lead to near blizzard conditions at times, especially out towards the Quad Cities  and IL/IA border area.

Central Illinois...
Precipitation will spread across Central Illinois later Sunday night and Monday 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 generally see freezing rain and sleet for the duration of the storm.

Southern Illinois...
Rain will spread into Southern Illinois Sunday night, and will then continue in periods through Tuesday morning. Isolated t'storms will be possible at times. Rainfall totals in excess of 1.00" is expected across Southern Illinois.

What's expected...
A swath of heavy snowfall totals of 6-12" is expected across Northern Illinois, with higher amounts possible near the IL/IA and further west. 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 0.10-0.25" is expected in an axis across Central Illinois.

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

JP

(11:00AM - 1/23/21) A disturbance will move through the region today through Sunday, bringing a minor/nuisance accumulating snowfall to portions of the state. ***Note: This is not to be mixed up with a separate winter storm that will affect the state, Monday morning through Tuesday morning. That is being discussed in separate updates (Click).***

​Summary...
A disturbance will move through the region today through Sunday. This disturbance and associated warm air advection will lead to periods of snow across Northern Illinois, early tonight through early Sunday afternoon. Model guidance has been and continues to be in good agreement regarding this event, thus little to no change is needed with this update.

Forecast...
​Areas of snow and snow showers developing across the Northern Plains and Midwest today will spread eastward. This activity will first enter Northwest Illinois early tonight, steadily spreading across the rest of Northern Illinois overnight tonight. This activity will then continue in periods across Northern Illinois, through midday or early afternoon on Sunday, before coming to an end.

​What's Expected...
Final snowfall totals upwards of a dusting to 1" or so are expected across Northern Illinois and portions of Central Illinois, with upwards of 1-3" possible across far Northern and Northwest Illinois.

​Below is the snowfall forecast for this event.

JP

(10:30PM - 1/22/21) A disturbance will move through the region on Saturday and Sunday, bringing a minor/nuisance accumulating snowfall to portions of the state. ***Note: This is not to be mixed up with a separate winter storm that will affect the state, Monday morning through Tuesday morning. That is being discussed in separate updates (Click).***

​Summary...
A disturbance will move through the region Saturday and Sunday. This disturbance and associated warm air advection will lead to periods of snow across Northern Illinois, Saturday evening through early Sunday afternoon. Model guidance has been and continues to be in good agreement regarding this event, thus little to no change is needed with this update.

Forecast...
​Areas of snow and snow showers will develop across the Northern Plains and Midwest on Saturday. This activity will then spread eastward, making it into Northwest Illinois Saturday evening or Saturday night, and eventually spreading across the rest of Northern Illinois overnight Saturday night. This activity will then continue in periods across Northern Illinois, through midday or early afternoon on Sunday. 

​What's Expected...
Final snowfall totals upwards of a dusting to 1" or so are expected across much of Northern Illinois, with upwards of 1-3" possible across far Northern and Northwest Illinois.

​Below is the snowfall forecast for this event.

JP

(9:00PM - 1/22/21) A storm system is expected to move through the region, Monday through Tuesday. This winter storm is expected to bring accumulating snow to portions of the state. In addition to the snow, a corridor of accumulating sleet and ice is possible. ***Note: This is not to be mixed up with a separate disturbance which will bring a minor accumulating snow event to Northern Illinois, Saturday night into Sunday. That will be discussed in separate updates.***

Summary...
​Over the past several days model guidance has been honing in on the potential for a winter storm to affect the region, Monday through Tuesday morning. It is now looking likely that this winter storm will impact the state with accumulating snow, sleet and ice. However, there is still disagreement within model guidance regarding the track and strength of this system, which will affect the location of the snowfall axis and snowfall amounts...as well as sleet and ice location and amounts. It should be noted that through the day today, the amount of disagreement and uncertainty has within model guidance has narrowed. With that said, we will hold off on specific snow/sleet/ice totals and other specifics for now given the continued uncertainty and the fact we're still about 2 1/2 days away from the start of the event.

What we know....
-A storm system will move through the region Monday through Tuesday.
-Precipitation will spread across the state, Monday morning through Tuesday morning.
-An axis of snow/sleet/ice will slice across the state, with Northern and Central Illinois being favored at this time.
-Several inches of accumulating snow is likely where the main snowfall axis sets up.
-A corridor of accumulating sleet and ice is also expected, and the south end of the snowfall axis.

What we don't know...
-The exact track and strength of the storm system.
-The location of the snowfall axis, and expected snowfall amounts.

JP

(11:45AM - 1/16/21) A disturbance will move through the region on Saturday and Sunday, bringing a minor/nuisance accumulating snowfall to portions of the state. ***Note: This is not to be mixed up with a separate winter storm that will affect the state, Sunday night-Tuesday morning. That is being discussed in separate updates (Click).***

​Summary...
A disturbance will move through the region Saturday and Sunday. This disturbance and associated warm air advection will lead to periods of snow across Northern Illinois, Saturday evening through early Sunday afternoon. Model guidance has and continues to be in good agreement regarding this event.

​Forecast...
​Areas of snow and snow showers will develop across the Northern Plains and Midwest on Saturday. This activity will then spread eastward, making it into Northwest Illinois Saturday evening, and eventually spreading across the rest of Northern Illinois Saturday night. This activity will then continue in periods across Northern Illinois, through midday or early afternoon on Sunday. 

​What's Expected...
Final snowfall totals upwards of a dusting to 1" or so are expected across much of Northern Illinois, with upwards of 1-3" possible across far Northern and Northwest Illinois.

​Below is the snowfall forecast for this event.

JP

(7:30PM - 1/21/21) A storm system is expected to move through the region, Sunday through Tuesday. This storm system has the potential to bring accumulating snow to portions of the state, in addition to some sleet and ice potential. ***Note: This is not to be mixed up with a separate disturbance which will bring a minor accumulating snow event to Northern Illinois, Saturday night into Sunday. That will be discussed in separate updates.***

Summary...
​Over the past several days model guidance has been honing in on the potential for a winter storm to affect the region, Sunday night through Tuesday morning. While the potential for a winter storm to affect the state has been steadily increasing, there is still uncertainty regarding track and strength of this system, which will affect the location of the snowfall axis and snowfall amounts.

What we know...
-A storm system will move through the region Sunday through Tuesday.
-Precipitation will spread across the state, Sunday night through Tuesday morning.
-An axis of snow/sleet/ice will slice across the state, with Northern and Central Illinois being favored at this time.
-Several inches of accumulating snow possible where the main axis sets up.

What we don't know...
-The exact track and strength of the storm system.
-The location of the snowfall axis, and expected snowfall amounts.

JP

​(10:15PM - 1/16/21) A fast moving disturbance will move through the region tonight through Sunday night, bringing a minor/nuisance accumulating snowfall to a large portion of the state.

​Summary...
A fast moving and potent disturbance will move through the region tonight through Sunday night. An associated area of snow and snow showers will spread across the state from tonight/very early Sunday morning through Sunday night. Model guidance has been and continues to be in good agreement regarding this event. As has been the case with the past few updates, little to no change was needed with this update.

​Forecast...
​Areas of snow and snow showers will develop across Minnesota, Iowa, Wisconsin and Northwest Illinois tonight. This activity will then spread eastward across a large portion of the state, from tonight/very early Sunday morning through Sunday night. Activity will generally remain on the light or showery side for the duration of the event.​ This disturbance will be working with a limited amount of moisture, thus snowfall totals will remain on the minor/light side.

​What's Expected...
Final snowfall totals upwards of a dusting to 1.5" or so are expected across a large portion of the state. A corridor of locally higher amounts will be possible across portions of Northern/Central Illinois.

​Below is the snowfall forecast for this event.