(7:15PM Monday - 2/28/22) A brief recap regarding the Wed-Fri, Feb 23-25th winter storm that brought a swath of accumulating snow/sleet/ice across the region and state during this time.

Overview...
A storm system impacted the region Wednesday, Feb 23rd through Friday, Feb 25th, which brought a swath of accumulating snow/sleet/ice across the region and state during this time. Model guidance showed the potential for this winter storm several days out, and in the end this winter storm produced overall very close to forecast expectations. ​An initial lead wave moved through the Ohio Valley Wednesday through Wednesday night, bringing with it an initial round of wintry precipitation across the southern half of the state. Furthermore, a main storm system developed across the Southern Mississippi Valley Thursday morning, which then tracked near the Ohio Valley Thursday afternoon through Thursday night, and eventually into the Mid-Atlantic by Friday morning. This storm system brought a renewed push of wintry precipitation across the region and state, Thursday morning through Friday morning.

Wednesday Afternoon - Thursday Morning, Feb 23-24th ~ Lead Wave Event:
An initial lead wave moved through the Ohio Valley Wednesday through Wednesday night, with an associated area of precipitation traveling along with it. Precipitation in the form of a mix of freezing rain/sleet/snow pushed across Southern Illinois, Wednesday afternoon through Thursday morning. This period of mixed precipitation brought light accumulations of snow/sleet/freezing rain across Southern Illinois during this time.

Thursday Morning - Friday Morning, Feb 24-25th ~ Main Winter Storm Event:
​As the main storm system moved through the region, an associated renewed push of precipitation also pushed across the state and region, Thursday morning through Friday morning. This renewed push of precipitation, in the form of snow/sleet/ice, moved into portions of Western and Southwestern Illinois mid to late Thursday morning. This area of precipitation then further developed and spread across much of the state from midday Thursday through Thursday night, before ending by late Thursday night and early Friday morning. A transition zone 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 other portions of Central Illinois, all of the precipitation fell as snow. Snow varied in intensity, but was generally light to moderate at times, with snowfall rates of 0.5"+ an hour at times.

​In additional to the synoptic aspect to this winter storm period, conditions were favorable for some lake enhanced and lake effect snow across portions of Northeast Illinois, Wednesday night through Friday morning. This enhanced snowfall totals a bit for affected areas.
Below are map representations of the final forecasts and observed snowfall/sleet and ice totals across the state and adjacent areas. ​
​Below are the snowfall and ice forecasts for this winter storm.

​Wrap Up...
-An axis of accumulating snowfall with 1-3" totals occurred across Northern and Central Illinois, with higher snowfall amounts of 2-5" across portions Northeast Illinois.
-An axis of significant freezing rain/ice accumulations of a 0.10" ot 0.50" occurred across far Southern Illinois.
-Scattered tree damage and power outages occurred across far Southern Illinois, due to the freezing rain/ice.

JP

(6:00PM Monday - 2/28/22) A brief recap regarding the Wed-Thur, Feb 16-17th winter storm that brought a swath of accumulating snow/sleet/ice, heavy rainfall with localized to scattered flooding, and an isolated severe t'storm risk across the region and state during this time.

Overview...
A storm system impacted the region Wednesday, Feb 16th through Thursday, Feb 17th, bringing a swath of accumulating snow/sleet/ice, heavy rainfall with localized to scattered flooding, and an isolated severe t'storm risk across the region and state during this time. Model guidance showed the potential for this winter storm several days out, and in the end this winter storm produced overall very close to forecast expectations. A cold front moved through the region Wednesday and Wednesday night, associated with a storm system moving through Southern Canada. This frontal boundary became nearly stationary by Thursday morning, near the Ohio Valley in the region and Southern Illinois. Furthermore, a storm system developed in the Southern Plains Wednesday night, and then tracked through the Ohio Valley on Thursday, and eventually into the Northeast on Friday. This storm system brought a renewed push of precipitation and main impacts of this period across the region and state, Thursday morning through Thursday evening.

Wintry (Snow/Sleet/Ice) Aspect Summary...
Wednesday Night - Thursday Morning, Feb 16-17th ~ Cold Front/Lead Wave Event:
A cold front moved through the region Wednesday and Wednesday night, associated with a storm system moving through Southern Canada. This frontal boundary became nearly stationary by Thursday morning, near the Ohio Valley in the region and Southern Illinois. Precipitation in the form of rain developed ahead of the cold front, across portions of Missouri, Iowa, Northern/Central Illinois and Wisconsin, Wednesday afternoon. This area of rain continued to expand as it further developed and pushed northeastward, spreading into other portions of Northern and Central Illinois, Wednesday afternoon and evening. This activity continued across Northern and Central Illinois Wednesday night, and also started to push into Southern Illinois as well early Wednesday night, with it then continuing overnight Wednesday night. Isolated to scattered t'storms occurred with this activity across much of the state through Wednesday night as well. Colder air filtered in behind the cold front across Northern and Western Illinois, Wednesday night. As this colder air filtered in, rain transitioned to a mix of rain/freezing rain/sleet/snow across portions of Northern and Western Illinois overnight Wednesday night, which then continued into early Thursday morning. Some minor snow/sleet/ice accumulation occurred across portions of affected areas of Northern and Western Illinois, Wednesday night into early Thursday morning. In addition to precipitation, windy conditions featuring wind gusts of 30-45MPH occurred across the state much of the day on Wednesday

Thursday Morning - Thursday Evening, Feb 17th ~ Main Winter Storm Event:
​As the main storm system moved through the region, an associated renewed push of precipitation moved across the state and region with the main impacts, Thursday morning through Thursday evening. This renewed push of precipitation, in the form of snow/sleet/ice, pushed into Western Illinois by mid morning Thursday. This area of precipitation continued to spread across portions of Northern and all of Central Illinois through late Thursday afternoon, before ending Thursday evening. A transition zone set up and was in place much of the day Thursday across portions of Central Illinois, generally near and between I-72 and I-70. Across this zone, precipitation types will from south to north ranged from freezing rain to sleet to snow. This transition zone eventually changed over to snow for a time, before precipitation ended Thursday evening. North of this transition zone across affected areas of Northern and Central Illinois (Near/north of I-72), most precipitation fell as snow. Periods of moderate to heavy snow occurred at times, with snowfall rates of 1-2" an hour having occurred at times. Additionally, windy conditions occurred Thursday morning through Thursday evening across a large portion of the state. During this time wind gusts upwards of 20-40MPH occurred, which caused some blowing and drifting snow for areas experiencing snow, and near blizzard conditions at times. 

​​​Below are map representations of the final forecasts and observed snowfall/sleet and ice totals across the state and adjacent areas. 

​Severe T'Storm Risk/Heavy Rain/Flooding Aspect Summary...
Thursday Morning - Thursday Evening, Feb 17th ~ Severe T'Storm Event:
​The main risk for an isolated severe t'storm risk existed across far Southern Illinois, Thursday morning into Thursday afternoon. Areas of rain and isolated to scattered t'storms were ongoing Thursday morning across Southern Illinois, in the vicinity of a nearly stationary frontal boundary in place. An isolated severe t'storm was possible with that activity, but none reached that level. As the main storm system moved through the region, an arc of rain and t'storms accompanied the low pressure and cold front that swept across Southern Illinois, Thursday morning into Thursday afternoon. Ahead of this activity, an environment was in place supportive of some severe t'storm risk with this activity. However, in the end the severe t'storm activity ended up occurring just to the south of the state.

Wednesday Afternoon - Thursday Evening, Feb 16-17th ~ Heavy Rain/Flooding Event:
Persistent periods of rainfall occurred across the southern half of the state Wednesday afternoon through Thursday afternoon, associated both with a frontal boundary becoming stationary across Southern Illinois and the main storm system moving through. During this period of time, periods of heavier rainfall occurred as well. Widespread rainfall totals of 1-4" occurred across the southern half of the state during this period of time, with locally higher amounts. Due to the combination of frost depth/frozen ground and the heavy rainfall that occurred, localized to scattered flooding occurred. Further north across Northern and Central Illinois, rainfall totals of 0.50-2.00" occurred Wednesday afternoon through early Thursday morning, which lead to some instances of localized flooding, due to frozen ground not being able to absorb lingering snow melt and rainfall.

​​Below is a map representation of the observed rainfall totals across the state and adjacent areas. 

Wrap Up...
-An axis of accumulating snowfall occurred across the heart of the state, with snowfall totals upwards of 4-9" in the main corridor. Snowfall amounts quickly tapered north and south of this main axis, across Northern and Central Illinois.
-An axis of freezing rain/ice accumulations of a glaze to 0.10" occurred across portions of Central and Southern Illinois, with locally higher amounts of 0.10"+.
​-An isolated severe t'storm threat was possible across Southern Illinois Thursday morning through Thursday afternoon, however this activity stayed just south of the state.
-Widespread heavy rainfall occurred across the southern half of the state, with widespread rainfall totals of 1-4". These rainfall totals will cause localized to scattered flooding for affected areas.
-Windy conditions on Wednesday of 30-45MPH and Thursday of 20-40MPH, which caused blowing and drifting snow across the heart of the state on Thursday.
-Significant and widespread travel impacts occurred across much of the state, especially across the heart of the state.​

JP

(10:45AM - 2/24/22) A winter storm will continue to impact the region and state, through early Friday morning. This winter storm will produce a swath of accumulating snow/sleet/ice across the region and state during this time.

Summary...
Real time observations and model guidance continues to support the going forecast. The main changes with this update were to bring the potential for some freezing rain/ice accumulation a bit further north into Central Illinois, as well as increase snowfall accumulation to 2-5" across Northeast Illinois due to increased confidence in lake effect snow contribution

​An initial lead wave moved through the Ohio Valley Wednesday through Wednesday night, bringing with it an initial round of wintry precipitation across the southern half of the state. Furthermore, a main storm system is developing across the Southern Mississippi Valley this morning, and is expected to track near the Ohio Valley this afternoon and tonight, 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, this morning through Friday morning.

Wintry (Snow/Sleet/Ice) Aspect Forecast...
Wednesday Afternoon - Thursday Morning, Feb 23-24th ~ Lead Wave Event:
An initial lead wave moved through the Ohio Valley Wednesday through Wednesday night, with an associated area of precipitation traveling along with it. Precipitation in the form of a mix of freezing rain/sleet/snow pushed across Southern Illinois, Wednesday afternoon through Thursday morning. This period of mixed precipitation brought light accumulations of snow/sleet/freezing rain across Southern Illinois during this time.

This 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, this morning through Friday morning. This renewed push of precipitation, in the form of snow/sleet/ice, is moving into portions of Western and Southwestern Illinois mid to late this morning. This area of precipitation will further develop and spread across much of the state from midday today through tonight, before ending by late tonight or 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 other portions of 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, 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.

​​​​​​​Impacts...
-An axis of of snow/sleet accumulation of 1-3" across Northern and Central Illinois, with 2-5" of snowfall accumulation in Northeast Illinois near Lake Michigan. Sleet accumulation of a dusting to 1" across Southern Illinois.
-Ice accumulations of a glaze (Up to 0.10") to 0.10-0.25" across Southern Illinois.
​-Tree damage and power outages possible across far Southern Illinois, due to ice accumulation.
-Widespread travel impacts likely across much of the state.

JP

(10:00PM - 2/23/22) A winter storm will continue to impact the region and state, tonight 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.

Summary...
A large majority of model guidance continues to show a consensus solution regarding this winter storm. Additionally, as the first wave of this winter storm has been impacting Southern Illinois today and tonight, observational trends support the going forecast as well. Thus, our previous forecast is on track with little to no change needed with this update.

​An initial lead wave has been moving through the Ohio Valley today and will continue to through tonight, 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...
Tonight - Thursday Morning, Feb 23-24th ~ Lead Wave Event:
A lead wave has been moving through the Ohio Valley today and will continue to through tonight, with an associated area of precipitation traveling along with it. Precipitation in the form of a mix of freezing rain/sleet/snow has been pushing across Southern Illinois this afternoon into early tonight. While the initial bust of heavier precipitation has already passed, light and scattered mixed precipitation in the form of freezing rain/sleet/snow will continue at times across Southern Illinois tonight and into 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 to late 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 late Thursday night or 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.

​​​​​​Impacts...
-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.

JP

​(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.

Summary...
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.

​​​​​Impacts...
-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.

JP

​(9:30PM - 2/21/22) A winter storm is expected to impact the region and state, Wednesday 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.

Summary...
Now at the 18-24 hours point out from the beginning of this winter storm and there continues to be a bit of model guidance disagreement regarding a few aspects of this winter storm at this time. However, a large majority of model guidance continues to show a consensus solution, which is what our forecast continues to be based around with good confidence and little to no change needed with this update. Stay tuned to updates over the next several days regarding this winter storm.

​An initial lead wave is expected to move through the Ohio Valley Wednesday 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 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...
Wednesday Afternoon - Thursday Morning, Feb 23-24th ~ Lead Wave Event:
A lead wave is expected to move through the Ohio Valley, Wednesday afternoon through Thursday morning, with an associated area of precipitation traveling along with it. Precipitation in the form of a mix of rain/freezing rain/sleet/snow will move into Southwestern Illinois Wednesday afternoon. A transition zone will set up much of this period across Southern Illinois. Across this zone, precipitation types will from south to north will range from freezing rain to sleet to snow. This area of rain will expand as it further develops and pushes northeastward, continuing to spread across Southern Illinois Wednesday night, before ending Thursday morning. A lull in precipitation may occur between this lead wave and the main storm system to follow.

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 Southwestern Illinois Thursday morning. This area of precipitation will then further develop and spread across much of the state from midday Thursday through late Thursday night, before ending Friday morning. A transition zone will set up much of this period across Southern Illinois. Across this zone, precipitation types will from south to north will range from freezing rain to sleet to snow. 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, 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, Thursday morning 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.

​​​​Impacts...
-An axis of of snow/sleet accumulation of 1-3" across Northern and Central Illinois, with locally higher amounts possible.
-Ice accumulations of a glaze (Up to 0.10") to 0.10"+ across Southern Illinois.
-Widespread travel impacts likely across much of the state.

JP

​(11:15AM - 2/21/22) A winter storm is expected to impact the region and state, Wednesday 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.

Summary...
While there continues to be a bit of model guidance disagreement regarding this storm system at this time, a large majority of model guidance continues to show a consensus solution, which is what our forecast continues to be based around with good confidence and little to no change needed with this update. Stay tuned to updates over the next several days regarding this winter storm.

​An initial lead wave is expected to move through the Ohio Valley Wednesday 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 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...
Wednesday Afternoon - Thursday Morning, Feb 23-24th ~ Lead Wave Event:
A lead wave is expected to move through the Ohio Valley, Wednesday afternoon through Thursday morning, with an associated area of precipitation traveling along with it. Precipitation in the form of a mix of rain/freezing rain/sleet/snow will move into Southwestern Illinois Wednesday afternoon. A transition zone will set up much of this period across Southern Illinois. Across this zone, precipitation types will from south to north will range from freezing rain to sleet to snow. This area of rain will expand as it further develops and pushes northeastward, continuing to spread across Southern Illinois Wednesday night, before ending Thursday morning. A lull in precipitation may occur between this lead wave and the main storm system to follow.

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 Southwestern Illinois Thursday morning. This area of precipitation will then further develop and spread across much of the state from midday Thursday through late Thursday night, before ending Friday morning. A transition zone will set up much of this period across Southern Illinois. Across this zone, precipitation types will from south to north will range from freezing rain to sleet to snow. 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, with snowfall rates of 0.5"+ an hour possible at times. 

​Below are the snowfall and ice forecasts for this winter storm.

​​​Impacts...
-An axis of of snow/sleet accumulation of 1-3" across Northern and Central Illinois.
-Ice accumulations of a glaze (Up to 0.10") to 0.10"+ across Southern Illinois.
-Widespread travel impacts likely across much of the state.

JP

(10:15PM - 2/21/22) A winter storm is expected to impact the region and state, Wednesday 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.

Summary...
Over the past several days model guidance has been honing in on the potential for a winter storm to affect the region and state, Wednesday through Friday. While there continues to be some model guidance disagreement regarding this storm system at this time, a large majority of model guidance is showing a consensus solution, which is what our current forecast is based around with good confidence. As stated, there still does continue to be some disagreement within model guidance at this time, so some changes to the forecast can be expected until full agreement on the situation is reached. Stay tuned to updates over the next several days regarding this winter storm.

​An initial lead wave is expected to move through the Ohio Valley Wednesday 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 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...
Wednesday Afternoon - Thursday Morning, Feb 23-24th ~ Lead Wave Event:
A lead wave is expected to move through the Ohio Valley, Wednesday afternoon through Thursday morning, with an associated area of precipitation traveling along with it. Precipitation in the form of a mix of rain/freezing rain/sleet/snow will move into Southwestern Illinois Wednesday afternoon. A transition zone will set up much of this period across Southern Illinois. Across this zone, precipitation types will from south to north will range from freezing rain to sleet to snow. This area of rain will expand as it further develops and pushes northeastward, continuing to spread across Southern Illinois Wednesday night, before ending Thursday morning. A lull in precipitation may occur between this lead wave and the main storm system to follow.

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 Southwestern Illinois Thursday morning. This area of precipitation will then further develop and spread across much of the state from midday Thursday through late Thursday night, before ending Friday morning. A transition zone will set up much of this period across Southern Illinois. Across this zone, precipitation types will from south to north will range from freezing rain to sleet to snow. 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, with snowfall rates of 0.5"+ an hour possible at times. 

​Below are the snowfall and ice forecasts for this winter storm.

​​Impacts...
-An axis of of snow/sleet accumulation of 1-3" across Northern and Central Illinois.
-Ice accumulations of a glaze (Up to 0.10") to 0.10"+ across Southern Illinois.
-Widespread travel impacts likely across much of the state.

JP

​​(9:45PM - 2/21/22) A winter storm is set to impact the region and state, tonight through Tuesday afternoon. This winter storm is expected to produce a swath of accumulating freezing rain/ice, heavy rainfall with localized to scattered flooding potential, and an isolated to sporadic severe t'storm risk across the region and state during this time.

Summary...
Model guidance continues to be in good agreement regarding this winter storm, thus making for a high confidence forecast. With this update we have upgraded severe t'storm probabilities across Southern Illinois, as well as increased flood probabilities across Southern Illinois...As confidence in the given forecast scenario grows based on real time observations today/tonight.

​A storm system will develop across the Plains tonight, with it then tracking across Illinois and through the Midwest and Great Lakes on Tuesday, and eventually into the Northeast by Wednesday morning. This winter storm is expected to produce a swath of accumulating freezing rain/ice, heavy rainfall with localized to scattered flooding potential, and an isolated to sporadic severe t'storm risk across the region and state during this time.

​Wintry (Snow/Sleet/Ice) Aspect Forecast...
Tonight - Tuesday Afternoon, Feb 21-22nd ~ Freezing Rain/Ice Event:
The area low pressure with this storm system is expected to move across Northern Illinois early Tuesday morning through Tuesday afternoon. This will limit the wintry side of the storm system to far Northern Illinois, near the Illinois/Wisconsin border. Across this area, temperatures will be colder at the surface, with a northerly flow on the north side of the storm system. As several periods of precipitation develop and move across this area tonight through Tuesday afternoon, freezing rain is possible for areas closer to the Illinois/Wisconsin border. An isolated t'storm can't be ruled out either, in which case it would be an instance of thunder-freezing rain. It is also possible that if an isolated t'storm occurs, that some sleet would be possible for a time due to convective processes. 

​Below is the ice forecast for this winter storm.

​Severe T'Storm Risk/Heavy Rain/Flooding Aspect Forecast...
Tonight - Tuesday afternoon, Feb 21-22nd ~ Severe T'Storm Event:
​The main risk for an isolated to sporadic severe t'storm risk will exist across Southern Illinois, tonight through Tuesday afternoon. A complex of rain and t'storms has developed this evening and early tonight across portions of Oklahoma and Texas. This complex is expected to grow upscale as it pushes northeastward, eventually moving across Southern Illinois later tonight through Tuesday afternoon. Ahead of this activity, an environment will be in place supportive of some severe t'storm risk with this activity. This environment will feature low instability of up to 1,500J/KG, dew points in the mid 50's to low 60's, good shear, good forcing, and good lapse rates of 5.5-8.0C. This environment will be supportive of upwards of an isolated to sporadic severe t'storm risk (levels 1-2) across Southern Illinois. Damaging winds, hail and an isolated tornado will be the severe weather threats.

Tonight - Tuesday Afternoon, Feb 21-22nd ~ Heavy Rain/Flooding Event:
The same complex of rain and t'storms that is expected to move across Southern Illinois tonight through Tuesday afternoon producing a severe t'storm threat, will also bring a heavy rain/flooding threat to the same areas. This complex is expected to produce heavy rainfall, with widespread rainfall totals of 1-3" in a corridor across Southern Illinois during this period of time, with locally higher amounts possible. Due to the combination of recent heavy rainfall/flooding and the expected rainfall, localized flooding is expected.

Below are the severe t'storm and heavy rain/flooding forecast for this winter storm.

​Impacts...
-Ice accumulations of a glaze (Up to 0.10") across far Northern Illinois near the IL/WI border, with an axis of 0.10"+ ice accumulation across far Northwest Illinois.
​-An isolated to sporadic severe t'storm threat across Southern Illinois, later tonight through Tuesday afternoon.
-Widespread heavy rainfall across Southern Illinois, with a corridor of widespread rainfall totals of 1-3"+ expected. These rainfall totals could cause localized to scattered flooding potential for affected areas.
-Travel impacts likely both for far Northern Illinois due to the freezing rain and across Southern Illinois due to the heavy rain/flood potential.

JP

​​(11:00AM - 2/21/22) A winter storm is set to impact the region and state, this evening through Tuesday afternoon. This winter storm is expected to produce a swath of accumulating freezing rain/ice, heavy rainfall with localized flooding potential, and an isolated severe t'storm risk across the region and state during this time.

Summary...
Over the past several days model guidance has been honing in on the potential for a winter storm to affect the region and state, today through Tuesday. Model guidance has actually been in fairly good agreement regarding this storm system for several days now, thus making for a high confidence forecast.

​A storm system will develop across the Plains today and tonight, with it then tracking across Illinois and through the Midwest and Great Lakes on Tuesday, and eventually into the Northeast by Wednesday morning. This winter storm is expected to produce a swath of accumulating freezing rain/ice, heavy rainfall with localized flooding potential, and an isolated severe t'storm risk across the region and state during this time.

​Wintry (Snow/Sleet/Ice) Aspect Forecast...
Tonight - Tuesday Afternoon, Feb 21-22nd ~ Freezing Rain/Ice Event:
The area low pressure with this storm system is expected to move across Northern Illinois early Tuesday morning through Tuesday afternoon. This will limit the wintry side of the storm system to far Northern Illinois, near the Illinois/Wisconsin border. Across this area, temperatures will be colder at the surface, with a northerly flow on the north side of the storm system. As several periods of precipitation develop and move across this area tonight through Tuesday afternoon, freezing rain is expected for areas closer to the Illinois/Wisconsin border. An isolated t'storm can't be ruled out either, in which case it would be an instance of thunder-freezing rain. It is also possible that is an isolated t'storm occurs, that some sleet would be possible for a time due to convective processes. 

​Below is the  ice forecast for this winter storm.

​Severe T'Storm Risk/Heavy Rain/Flooding Aspect Forecast...
Tonight - Tuesday afternoon, Feb 21-22nd ~ Severe T'Storm Event:
​The main risk for an isolated severe t'storm risk will exist across Southern Illinois, tonight into Tuesday afternoon. Isolated to scattered showers and t'storms are expected to develop this evening and into tonight across portions of Arkansas, Missouri, Tennessee, Kentucky, Indiana and Southern Illinois, associated with a warm front lifting northward and strong warm air advection. An isolated t'storm with this activity may be strong to severe across Southern Illinois. The main focus will come later, as complex of rain and t'storms is expected to develop this evening across portions of Oklahoma and Texas. This complex will then grow upscale as it pushes northeast ward, eventually moving across Southern Illinois later tonight through Tuesday afternoon. Ahead of this activity, an environment will be in place supportive of some severe t'storm risk with this activity. This environment will feature low instability of up to 1,500J/KG, dew points in the mid 50's to low 60's, good shear, good forcing, and good lapse rates of 5.5-8.0C. This environment will be supportive of upwards of an isolated severe t'storm risk (levels 1) across Southern Illinois. Damaging winds, hail and an isolated tornado will be the severe weather threats.

Tonight - Tuesday Afternoon, Feb 21-22nd ~ Heavy Rain/Flooding Event:
A large complex of rain and t'storms is expected to move across Southern Illinois, tonight through Tuesday afternoon. This complex is expected to produce heavy rainfall, with widespread rainfall totals of 1-3" in a corridor across Southern Illinois during this period of time, with locally higher amounts possible. Due to the combination of recent heavy rainfall/flooding and the expected rainfall, localized flooding is expected.

Below are the severe t'storm and heavy rain/flooding forecast for this winter storm.

​Impacts...
-Ice accumulations of a glaze (Up to 0.10") across far Northern Illinois near the IL/WI border, with an axis of 0.10"+ ice accumulation across far Northwest Illinois.
​-An isolated severe t'storm threat across Southern Illinois, later tonight through Tuesday afternoon.
-Widespread heavy rainfall across Southern Illinois, with a corridor of widespread rainfall totals of 1-3"+ expected. These rainfall totals could cause localized flooding potential for affected areas.
-Travel impacts likely both for far Northern Illinois due to the freezing rain and across Southern Illinois due to the heavy rain/flood potential.

JP