(11:45PM – Saturday, December 27th, 2025) Impacts in the form of severe t’storms, high winds, and snow expected across the state on Sunday and Monday…
❗Update…
•With this update, little in the way of changes were needed to going forecasts.
⏰Timing…
•Severe T’Storm Threat: Sunday Morning – Sunday Evening, December 28th.
•High Winds: Sunday Midday – Monday Afternoon, December 28-29th.
•Snow: Sunday Evening – Monday Morning, December 28-29th.
📍Location…
•Severe T’Storm Threat: Much of Illinois.
•High Winds: All of Illinois.
•Snow: Northern Illinois.
⚡️💨❄️Hazards…
•A level 1 severe t’storm threat is in place across much of Illinois between Sunday morning and Sunday evening for the threat of isolated severe t’storms. Damaging winds, hail and a tornado or two will be the main threats with activity.
•Peak high wind gusts of 35-50MPH will be likely across the state between Sunday midday and Monday afternoon. Winds will be westerly to northwesterly. The high winds will have the potential to blow around light-weight/loose items and may cause isolated tree damage.
•Snowfall accumulation of a dusting to 1″ will be possible across portions of Northern Illinois between Sunday evening and Monday morning.
✔️Summary…
•As a potent storm system moves through the region, impactful weather is likely across the state on Sunday and Monday.
•Widespread rain and t’storm activity will traverse the state on Sunday, as a warm front lifts northward across the state and then a cold front quickly sweeps eastward across the state. Two rounds of potential t’storm activity that will be of focus to feature severe t’storm potential. There first will be across portions of Northern and Central Illinois on Sunday morning. The second round will be across much of the state from Sunday midday into Sunday evening.
•Strong cold air advection will occur across the state in the wake of the cold frontal passage, on the backside of the storm system. With a strong low-level jet and adequate atmospheric mixing, a period of high synoptic winds will be likely across the state from Sunday midday through Monday afternoon.
•As much colder air quickly moves in on the backside of the storm system and precipitation wraps around, snow/snow showers will traverse portions of Northern Illinois from Sunday evening through Monday morning.