textproduct: Central Illinois

KEY MESSAGES

- The primary concern is dangerously cold temperatures, particularly late tonight and Monday morning when there is reasonably high confidence that wind chill values will fall between 10 and 20 degrees below zero. HREF has an 80-100% chance of wind chills lowering to 10 below or colder over central IL and 50-70% chance to 10 below or colder in southeast IL by dawn Monday.

- An active storm track will bring a series of quick-moving systems to the region over much of this week. While significant snow accumulations are not forecasted over central and southeast IL, these disturbances will produce periodic organized snow showers, which may lead to periods of reduced visibility.

DISCUSSION

Issued at 245 PM CST Sun Jan 18 2026

Extended the Cold Weather Advisory further south to include Effingham, Jasper, Crawford, Clay, Richland and Lawrence counties from 3 am to noon on Monday, for wind chills getting down to 10 below by dawn Monday morning. Forecast models have increased wind speeds a bit more behind the arctic cold front passing through during tonight and lowering wind chills more.

At 20Z/2 pm, a 1025-1027 mb high pressure over southeast Texas was ridging northeast into the Ohio river valley. A 1009 mb low pressure over western Lake Superior had an arctic cold front into nw WI, central Iowa and nw MO. Broken to overcast mid level clouds with bases from 8-10k ft quickly spread east over CWA past few hours while some broken stratocumulus clouds with bases of 2-3k ft lingered over parts of Champaign and Vermilion counties, mainly east of Champaign/Savoy airport. Radar mosaic shows light echo returns nw of BMI and Lincoln but may just be flurries at best since not seeing may ground truth reports of light snow over nw CWA. Aloft a short wave trof was over the upper MS river valley and helping produce light snow over parts of MN, WI and central and northern Iowa and into far nw IL by the Galena/Chestnut Mountain area. Cold temperatures were mostly in the lower 20s, ranging from 19F at Peoria and Lacon to mid 20s from highway 50 south. South to SW breezes of 10-20 mph and gusts 18-25 mph was giving wind chills in the single digits and lower teens.

We should see a band of light snow affect areas mainly from I-74 north during late afternoon into mid evening with mainly flurries possible elsewhere into this evening. We have a dusting to around a half inch of snow from I-74 north with 1 inch or more possible just north/NE of CWA where better forcing will be. The latest HRRR models has the Arctic cold front tracking quickly se to Galesburg by 8 pm, to the IL river by 9 pm, I-55 by 930-10 pm, near I-57 by 11 pm and pass the Wabash river between midnight-1 am tonight. SW winds to switch WNW to NW and increase to 15-25 mph and gusts 25-35 mph. The HREF has a 50-70% chance of wind gusts over 35 mph north of I-70 behind the arctic front, by mid evening over the IL river valley and east to the Indiana border by early overnight. Lows overnight mostly in the single digits, ranging from near zero by Galesburg to around 10F se of I-70. Wind chills lower to 15-22 below by dawn Monday morning from Jacksonville to Mattoon to Danville north and reaching 7-13 below in southeast IL.

Strong Canadian high pressure over the southern Canadian Prairie Provinces to settle into the Ozarks by sunset Monday and ridging into IL by Monday afternoon. This should keep us dry with return of some sunshine with mostly sunny skies Monday afternoon. But the sunshine will be deceiving with brisk WNW winds keeping very cold temperatures around. Highs Monday only in the low to mid teens in central IL and upper teens in southeast IL. Wind chills to gradually modify to 5 above to 5 below during Monday afternoon as winds gradually subside during Monday afternoon. The surface high pressure ridge settles into the lower MS and TN river valley by Tue morning and another cold night Mon night of 4-10F but lighter winds with lowest wind chills in the single digits below zero Mon night. Partly to mostly sunny skies Tuesday with highs in the mid to upper 20s central and ne CWA and lower 30s sw CWA and se IL.

A northern stream short wave system over nw Canada to dive into the upper Midwest Tue night and move into the central Great Lakes region by midday Wed. This could bring light snow as far south as central IL overnight Tue night into early Wed morning especially from I-74 north with just a dusting possible. West to SW breezes ahead of this system brings temps closer to normal for a day on Wed with highs in the mid to upper 30s central IL (lower 30s from Galesburg to Lacon north) and 40-45 in southeast IL. Another northern stream short wave skirting by north of IL during Wed night with slight chance of light snow or flurries far northern CWA. A very strong ~490 decameter 500 mb low digging southward over western Ontario Thu and passing northeast of the Great Lakes Friday keeps IL in cyclonic flow. Also have a strong ~1050 mb arctic high pressure settling se into the upper Midwest on Friday. Models have trended further southward this this strong high and also keeping southern stream storm systems further south of central IL late this week. Thu and Fri look drier over CWA and colder too as highs Thu drop back into the mid 20s to lower 30s (similar to Tue readings) with southeast IL reaching mid 30s Fri. Followed NBM pops which are slight chance light snow nw half of CWA Fri afternoon and 20-30% chance light snow Fri night, highest pops in southeast IL. ECMWF, GFS and GEM and their ensembles have trended further south with southern stream storm system this weekend into early next week and also have northern stream system ne of our area over the Great Lakes. We may be trending drier during this period but also more bitter cold air likely arriving during this weekend into early next week with lows back into the single digits. Plus wind chills could reach zero to 15 below overnight Fri night into Sat morning north of I-70 and 10-20 below over much of CWA overnight Sat night into next Sunday morning.

The Climate Prediction Center (CPC) 8-14 Day Outlook for Jan 26-Feb 1st has 65-75% chance of below normal temperatures over central and southeast IL, with 40-50% chance of below normal precipitation. CPC 3-4 Week Outlook for Jan 31-Feb 13th has a 33-40% chance of below normal temperatures over central and NE IL with equal chances of above or below normal precipitation.

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AVIATION

(For the 06z TAFs through 06z Monday Night) Issued at 930 PM CST Sun Jan 18 2026

An Arctic cold front will cross the terminals by 06z, veering winds WNW and increasing gusts to 25-30 kt. These gusts will be common through Monday afternoon then diminish around sunset. Isolated snow showers are possible especially near the I-74 terminals over the next few hours, so included VCSH, and there is a low probability that a SHSN will impact a terminal and reduce category briefly. Otherwise, ceilings will be near the MVFR/VFR threshold for KPIA- KBMI-KCMI overnight with most guidance supporting keeping predominant VFR conditions.

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ILX WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory from 3 AM to noon CST Monday for ILZ027>031-036>038-040>057-061>063-066>068-071>073.