An upper-level disturbance brought a period of light snow to central and southeast Illinois during the afternoon and evening of December 1st. with a few pockets approaching 4 inches from Macomb eastward to Lincoln and near Effingham.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS ILX wrote it up.
An upper-level disturbance brought a period of light snow to central and southeast Illinois during the afternoon and evening of December 1st. Snowfall amounts generally ranged from 1 to 3 inches...with a few pockets approaching 4 inches from Macomb eastward to Lincoln and near Effingham. Snow-covered roadways led to a fatal car crash in northern Knox County between Oneida and Wataga. No other traffic accidents were reported.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Lincoln, IL wrote its last area forecast discussion before the first event at Dec 1, 11:58 AM CST, 1 hour 2 minutes earlier. Its key messages:
Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 1158 AM CST Mon Dec 1 2025 .KEY MESSAGES... - A fast-moving storm system will bring another round of snow to central Illinois today and tonight. Snow accumulations will generally range between 2 and 5 inches. Plan on travel impacts this evening into the overnight where the more intense snow bands develop. - Much below normal temperatures will prevail through next weekend...with the coldest readings arriving Thursday night when 12z NBM guidance suggests a 50-70% chance of lows dipping below zero along and north of a Macomb to Tuscola line. && .DISCUSSION... Issued at 329 AM CST Mon Dec 1 2025 A broad mid-level trough sweeping across the Upper Midwest continues to tighten the height gradient over the region, with the latest QG diagnostics indicating a corridor of pronounced 700-mb Q-vector convergence centered directly over central and southeast Illinois between 18z and 06z. This supports a period of enhanced large-scale ascent, maximized late this afternoon into early evening. While moisture remains modest, the combination of synoptic lift and increasing mid-level FGEN (700-600 mb) should be sufficient to generate moderate to occasionally heavy snowfall, mainly north of I-70. The latest 00z HREF/LPMM QPF guidance exhibited a slight shift southward with the axis of heaviest QPF, and this trend was reaffirmed by the 06z HRRR/NAMnest guidance, which now focuses the axis along the I-72/Danville corridor. For this reason, we have expanded the Winter Weather Advisory further south. In general, the QPF amounts did not change much, with most of the region lying somewhere in between 0.1-0.3 inches. Cobb/NAM mesoscale output continues to suggest a SLR closer to 15:1 throughout the duration of this event, and even that might be considered modest given the deep/saturated DGZ. This suggests snowfall totals in the 2 to 5 inch range. And, where the HREF/RRFS LPMM QPF hints toward 0.4 to 0.5 inches within mesoscale banding, totals could exceed 6 inches locally. Confidence is high for an advisory-level snow because the Q-vector convergence and strengthening FGEN provide a robust dynamical forcing mechanism. However, actual totals will be sensitive to the mesoscale placement of banding. A shift of the band by 30-60 miles changes which counties get the higher totals. Forecast uncertainty remains an issue for areas near and south of I-70. Coarser guidance, such as the RAP13 model, suggests a second band of moderate snowfall could develop across far southeastern Illinois late tonight. This is associated with an area of sharpening mid-level FGEN (700-600 mb) and a compact shortwave pivoting across the Missouri Bootheel, which will augment forcing. However, the broad synoptic ascent appears weaker than the initial snow band that moves through central Illinois earlier in the day. This uncertainty, which is well-represented in recent CAMs (Convective-Allowing Models), is why we have paused on expanding the Winter Weather Advisory south of I-70. Since the potential second push of moderate snow across our southeast counties is not expected until after 00Z, we have time to monitor the trends and make adjustments as needed. Temperatures in central Illinois will oscillate between very cold and just plain cold this week due to shifting high pressure. A brief warming trend is forecast for Wednesday afternoon, offering the best chance for much of the area to finally climb above the freezing mark. This temporary warm-up is driven by a southwest wind shift ahead of a weak cold front approaching from the north. The passage of this front may bring a few snow showers Wednesday evening, but any accumulation is expected to be limited to a dusting. Following the front, a period of sharply colder air will settle in. There is high confidence that overnight lows will dip into the single digits on both Wednesday and Thursday nights. While a Cold Weather Advisory is currently unlikely, wind chill values are still anticipated to fall below zero. One notable trend in the extended forecast is a southward shift of the late week winter storm system. It is hard to tell if this is indeed the trend, or just a one-off with the latest round of model guidance. Nevertheless, the chance for a 1 inch snowfall across our area is now limited to a 1 in 7 chance, which is considerably lower than what we were seeing yesterday. Consequently, the freezing rain potential also diminished. MJA && .AVIATION... (For the 18z TAFs through 18z Tuesday Afternoon) Issued at 1157 AM CST Mon Dec 1 2025 1730z/1130am radar mosaic and regional observations indicate snow has spread as far east as the Mississippi River. Further east across central Illinois, ceilings have temporarily improved to VFR. Based on radar trends and HRRR/RAP timing, have introduced light snow and lowered ceilings to MVFR at KPIA/KSPI by 19z...then further east to KCMI by 21z. About an hour after the snow commences, think ceilings/visby will lower to IFR at all sites through mid-evening. CAMs have been consistently showing the snow ending from west to east across the area toward midnight, so have removed snow and raised visbys back up to 6 miles or more at KPIA by 03z...then to KCMI by 07z. Despite an end to the precip, forecast soundings suggest IFR ceilings will persist into Tuesday morning before slowly improving to MVFR toward midday. Winds will initially be E/SE at less than 10kt, then will veer to W/NW at 10kt or less late tonight into Tuesday. Barnes && .ILX WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 6 AM CST Tuesday for ILZ027>031- 036>038-040>057-061>063-066>068-071>073. &&
Hazardous Weather Outlook National Weather Service Lincoln IL 406 AM CST Mon Dec 1 2025 ILZ027>031-036>038-040>057-061-021015- Knox-Stark-Peoria-Marshall-Woodford-Fulton-Tazewell-McLean-Schuyler- Mason-Logan-De Witt-Piatt-Champaign-Vermilion-Cass-Menard-Scott- Morgan-Sangamon-Christian-Macon-Moultrie-Douglas-Coles-Edgar-Shelby- 406 AM CST Mon Dec 1 2025 This Hazardous Weather Outlook is for central Illinois, east central Illinois and west central Illinois. .DAY ONE...Today and tonight. Accumulating snow is likely this afternoon into tonight. The heaviest snow may occur near or just north of the Interstate 72 to Danville corridor where between 2 and 5 inches are forecast. Snow- covered roads and slippery travel is likely during this time. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. The overnight temperature on Wednesday and Thursday nights will edge near or below zero, with wind chill values between 5 and 10 below zero. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated through tonight. ILZ062-063-066>068-071>073-021015- Cumberland-Clark-Effingham-Jasper-Crawford-Clay-Richland-Lawrence- 406 AM CST Mon Dec 1 2025 This Hazardous Weather Outlook is for east central Illinois and southeast Illinois. .DAY ONE...Today and tonight. Accumulating snow is likely this evening. Between 1 and 3 inches are currently forecast. Snow- covered roads and slippery travel is likely during this time. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. The overnight temperature on Wednesday and Thursday nights will edge into the lower teens, with wind chill values nearing single digits. Additional light wintry weather is possible by Friday with snow and ice currently in the forecast. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated through tonight. MJA
The national radar mosaic for the moment the first event began.
1 winter weather. Local standard time, as filed.
A fresh snowfall of 1 to 3 inches led to snow-covered and hazardous roadways across Knox County during the afternoon and evening of December 2nd. A man was killed when his vehicle collided with a semi truck on US Route 34 between Oneida and Wataga.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Winter Weather, Knox | 2025-12-01 | 26 | Male | Vehicle/Towed Trailer | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2025Every state in 2025This day in weather historyWarnings in Illinois, December 2025
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1301290.