textproduct: Central Illinois

KEY MESSAGES

- The long-duration winter storm is gradually coming to an end. Additional snow amounts of up to 2" are possible east of I-55, with the best chance of additional snow accumulation being south of I-70. Snow should exit the area by 6 or 7 PM. Due to the light, fluffy nature of the snow, blowing and drifting will remain a concern through the day on Monday.

- Well below normal temperatures persist through the week. Wind chill values of 20 to 25 below zero are forecast overnight into Monday morning. Wind chill values of 10 to 20 below zero are possible each night Monday night through Friday night.

DISCUSSION

Issued at 204 PM CST Sun Jan 25 2026

*** WINTER STORM DEPARTS THIS EVENING ***

Our long duration winter storm is gradually coming to an end this afternoon. A 1008-mb sfc low was positioned over E KY/TN, resulting in northerly winds turning to northwesterly across IL this afternoon, with gusts still around 20-25 mph.

Around midday, a narrow snow band developed near/just west of the I-55 corridor, as weak fgen in the 700-500mb layer combined with lake- enhanced low-level moisture (925mb winds oriented from Lake Michigan to cntrl IL) and a deep DGZ, resulting in visbys falling to 1 mile or less within the band. This band weakened briefly, but has since regained strength as it extends from Champaign to Taylorville as of 1945z/145pm. Expect periods of moderate snow and lowered vis as this band pivots east through the afternoon. Due to the expected progressive nature and varying intensity of the band, it appears unlikely that additional snow amounts associated with it will exceed 1 inch, but I suppose localized 1-2 inch amounts can't be ruled out. Further SE, the next wave of snow is lifting northeast as anticipated. The heaviest precip is once again focused near/south of I-70, with vis down to 3/4 mile in spots. An additional 1-2" is possible through this evening, mainly near/south of I-70. Earlier reports indicated 8-12" fell near/south of I-70, which combined with this additional snowfall will continue to make travel very difficult in that region.

Precip is still on track to depart into IN by 00-01z/6-7 PM. No additional precip is expected through at least Tuesday. Wind gusts weaken slightly overnight into Mon, but will still gust around 20 mph. Due to the light, fluffy nature of the snow, blowing and drifting could continue to be an issue. The wind direction changes to westerly (rather than northwesterly) during the day on Monday, so north-south oriented roads may see more issues with blowing/drifting.

*** DANGEROUS COLD CONTINUES ***

As winter precip winds down, the return of dangerous cold becomes the main weather headline for central IL. With clear skies and fresh snow pack tonight, aired on the cool side of forecast guidance, with low temps around 5 degrees below zero. Combined with the persistent northwest flow, that will result in bitter, dangerous wind chills overnight into Monday morning. No changes were made to the cold weather headlines with this forecast package, with an Extreme Cold Warning covering portions of central and eastern Illinois, and a Cold Weather Advisory covering portions of central and west-central Illinois. Regardless of the specific headline in effect, expect wind chills of 15 to 25 below zero, which could cause frostbite on exposed skin in as little as 30 minutes.

The synoptic pattern remains slow to evolve this week, keeping troughing over the eastern US and continued anomalously cold conditions. With a moderate to deep snow pack across much of the CWA, remain concerned that any calm, clear night will result in temps being much cooler than forecast. Right now, the best candidate for this efficient radiational cooling is Tues night into Wed. Push low temps to near the overnight dewpoint values, which resulted in values of 0 to 10 below zero. At any rate, low temperatures are likely to be in the single digits above/below zero each day through this week, and minimum wind chill values of 15 to 20 below are possible each night east of the IL River. Additional Cold Weather Advisories may be needed as forecast confidence in reaching advisory criteria increases.

Deeper into the extended forecast, ensemble guidance does offer some indications of a gradual 'warming' trend, bringing highs temps close to freezing during the first days of Feb (20-50% chance of warmer than 32 degF).

*** NEXT PRECIP CHANCE? ***

With the main upper low anchored near the Hudson Bay, a weak clipper- style shortwave could offer a chance for light snow on Wed. This appears unlikely to produce accumulations. I thought perhaps that difference in the track of this subtle wave could be impacting the snow amounts, but both a cluster analysis and the 90th percentile snowfall suggest minimal amounts from this wave. We have just a 15- 20% chance of precip along the I-74 corridor in our forecast. Another weak precip chance exists Fri, but an encroaching sfc high will be pushing dry low-level air in from the north, reducing confidence that this weak wave will be able to amount to much.

All told, it looks like a bitterly cold but mostly dry January week across the ILX CWA.

Erwin

AVIATION

(For the 00z TAFs through 00z Monday Evening) Issued at 514 PM CST Sun Jan 25 2026

While a few flurries may persist this evening, the bulk of the accumulating snow has ended across central Illinois. Breezy NW winds are expected this evening and overnight, gradually backing to the west then southwest through the period. A broad area of ceilings ranging from 025-035 is currently in place across northern Illinois and spans SW into the lower Illinois River Valley. This is not being handled well by guidance, but extrapolating the motion on satellite suggests it will clear from the northwest overnight between 04Z at PIA to around 10-13Z at CMI. Outside of these ceilings, VFR conditions are expected the remainder of the period.

Deubelbeiss

ILX WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory from midnight tonight to noon CST Monday for ILZ027>031-036>038-040>042-047>051.

Extreme Cold Warning from midnight tonight to noon CST Monday for ILZ043>046-052>057-061>063-066>068-071>073.

Winter Storm Warning until 6 PM CST this evening for ILZ045-046- 055>057-062-063-066>068-071>073.