textproduct: Central Illinois

KEY MESSAGES

- A fast-moving storm system will bring another round of snow to central Illinois from Monday afternoon through Monday night. The highest accumulations of 2 to 4 inches will occur along and north of a Beardstown to Bloomington line.

- Much below normal temperatures will prevail through next weekend...with the coldest readings arriving Thursday night when 12z NBM guidance suggests a 40-60% chance of lows dipping below zero along and north of a Macomb to Tuscola line.

UPDATE

Issued at 835 PM CST Sun Nov 30 2025

Added mention of freezing fog to the grids after midnight along the I-72 corridor, primarily east of Springfield. Satellite imagery shows clearing working southwest through Champaign and Decatur. As winds go calm tonight and dewpoint depressions drop near zero in areas that clear out, short range guidance shows fog, some potentially dense, developing. Will monitor trends over the next several hours, but cannot rule out the eventual need for a focused Dense Fog Advisory. If dense fog does form, slick spots will likely develop as we head into the morning commute.

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LONG TERM

(Tuesday through Next Sunday) Issued at 142 PM CST Sun Nov 30 2025

Cold and dry weather with highs in the middle to upper 20s is anticipated for Tuesday before winds become S/SW ahead of the next approaching cold front and a brief warming trend into the middle 30s occurs on Wednesday. A few models are suggesting the cold front may be accompanied by a few snow-showers late Wednesday afternoon into Wednesday night: however, the dry boundary layer will prevent any appreciable precip. Once the front passes, strong CAA will spill into the region for Thursday...resulting in high temperatures struggling to reach 20 degrees everywhere north of I-70. As skies clear and winds diminish, bitterly cold conditions are expected Thursday night. 12z NBM guidance suggests a 40-60% chance of sub-zero lows along/north of a Macomb to Tuscola line. After that, yet another southern-stream storm system will spread moisture back into Illinois on Friday. The atmosphere will initially be cold enough to support all snow: however, as an elevated warm layer advects northward, there could potentially be some light freezing rain along/south of I-70 Friday night. It is still too early to pinpoint any specific snow/ice accumulations at this time. While the system will not be as strong as the one that impacted central Illinois yesterday, it has the potential to bring another light snow accumulation by the end of the week. Once this wave passes, cold and generally dry weather is expected next weekend.

Barnes

AVIATION

(For the 06z TAFs through 06z Monday Night) Issued at 940 PM CST Sun Nov 30 2025

A large hole has opened in the MVFR ceilings from KDEC-KCMI. Unsure how far west this clearing will extend overnight. Areas that due clear out stand a good chance to see IFR cig/vis develop, and have added this either as predominant or tempo conditions at all terminals except KPIA through 13-14z. Main forecast issue for Monday is an approaching storm system that will spread accumulating snow over the terminals during the afternoon. IFR conditions are likely for several hours with snow starting to taper off toward the end of this TAF period.

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ILX WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory from noon Monday to 6 AM CST Tuesday for ILZ027>031-036>038-040>043-047-048.