A storm system moved eastward from Minnesota into Michigan during the day bringing snow to eastern Iowa and northwest Illinois. The heaviest snow fall across northwest Illinois where snowfall amounts ranged from 2 to 5 inches in Carroll, Jo Daviess, Stephenson, and Whiteside Counties.
Every event with a place to put it; 4 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 DVN wrote it up.
A storm system moved eastward from Minnesota into Michigan during the day bringing snow to eastern Iowa and northwest Illinois. The heaviest snow fall across northwest Illinois where snowfall amounts ranged from 2 to 5 inches in Carroll, Jo Daviess, Stephenson, and Whiteside Counties.
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 Quad Cities, IA wrote its last area forecast discussion before the first event at Dec 11, 11:27 AM CST, 1 hour 18 minutes earlier.
Area Forecast Discussion National Weather Service Quad Cities IA IL 1127 AM CST Mon Dec 11 2017 ...18Z AVIATION UPDATE... .SYNOPSIS... Issued at 321 AM CST Mon Dec 11 2017 06Z surface data has an inferred boundary running from southwest Indiana, to near KEOK, and then west of KMCW. Another inferred boundary ran from KFSD into northern Kansas. Dew points were in the teens and 20s from the Great Lakes and Ohio Valley into the central and northern Plains. && .SHORT TERM...(Today and Tonight) ISSUED AT 321 AM CST Mon Dec 11 2017 Minor snow accumulations with the incoming system. A bigger concern will be the windy conditions later today and tonight. The main concern for the next 24 hours will be the windy conditions developing this afternoon and evening. Winds will increase to 20 to 30 mph with gusts up to 40 mph. The strongest winds look to occur late this afternoon and evening, or, roughly from 5 PM to midnight. Based on trends in observational data and the RAP, the initial shot of precipitation from the approaching system will give a glancing blow to the area through sunrise. Mainly flurries will be seen but some light snow is possible across northeast Stephenson county. Any accumulation there would be a dusting at best. After sunrise, the forcing associated with the initial round of precipitation will move east of the area creating a lull in activity. By mid to late morning and through the afternoon, forcing will increase again as the low moves through the area. Precipitation will break out across the area from mid to late morning and continue through the afternoon. Generally areas north of highway 30 have the best chance of seeing any precipitation. Precipitation will take on different forms depending upon how warm it becomes. A rain/snow mix that may at times be all snow is expected in the highway 20 corridor from Dubuque on east. South of the highway 20 corridor, light rain or sprinkles are expected that may mix with some light snow or flurries during the late afternoon hours. Accumulations by sunset will be mainly a dusting. This evening lingering flurries/sprinkles will end east of the the Mississippi. After midnight, dry conditions are expected. .LONG TERM...(Tuesday through Sunday) ISSUED AT 321 AM CST Mon Dec 11 2017 Continued overall dry to mostly dry pattern in northwest flow with minor to moderate day to day temperature changes. Long Term Forecast Confidence Assessment...fair or average with main issues diurnal trends with most days highs tending too low by 2 to 3 plus degrees and some lows too mild with clear skies and light winds by 2 to 3 plus degrees. Tuesday through Thursday...warming trend each day with mostly fair to fair skies. Low POPS Wednesday night are overdone and suggestive of flurries in northeast. Highs 25 to 35, rising to 30s to lower 40s Wednesday and Thursday. Mins teens rising into mostly the 20s. Friday through Monday...continued northwest flow with low chances for light precipitation. Highs in the 30s and 40s, mins mostly in the 20s. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon) ISSUED AT 1126 AM CST Mon Dec 11 2017 A fast moving low pressure system will spread fast moving rain and snow showers through the area this afternoon, along with developing strong surface winds. Precipitation is most likely to affect CID, DBQ and MLI this afternoon, followed by a period of low clouds with MVFR ceilings lingering into the evening. Northwest winds following this system will be sustained at 25 kts for a few hours with gusts possibly over 35 kts. While not included in the forecasts, flurries will be possible this evening. Winds will gradually decrease overnight and forecasts have winds dropping below 15 kts by Tuesday morning. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && SYNOPSIS...08 SHORT TERM...08 LONG TERM...Nichols AVIATION...Sheets
Hazardous Weather Outlook National Weather Service Quad Cities IA IL 337 AM CST Mon Dec 11 2017 IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007- 009-015>018-024>026-034-035-MOZ009-010-120945- Buchanan-Delaware-Dubuque-Benton-Linn-Jones-Jackson-Iowa-Johnson- Cedar-Clinton-Muscatine-Scott-Keokuk-Washington-Louisa-Jefferson- Henry IA-Des Moines-Van Buren-Lee-Jo Daviess-Stephenson-Carroll- Whiteside-Rock Island-Henry IL-Bureau-Putnam-Mercer-Henderson- Warren-Hancock-McDonough-Scotland-Clark- 337 AM CST Mon Dec 11 2017 This Hazardous Weather Outlook is for portions of north central Illinois...northwest Illinois...west central Illinois...east central Iowa...northeast Iowa...southeast Iowa and northeast Missouri. .DAY ONE...TODAY AND TONIGHT Winds of 20 to 30 mph with gusts approaching 40 mph will develop this afternoon and evening. The strongest winds should occur between 5 PM and midnight. A rain snow mix will be seen north of highway 30 today that will turn to all snow at times. Snow accumulations of less than an inch are possible north of a Manchester, Iowa, to Mount Carroll, Illinois line. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today or tonight. Any snowfall amounts of one half inch or more will be appreciated.
Special Weather Statement National Weather Service Quad Cities IA IL 1133 AM CST Mon Dec 11 2017 IAZ087>089-098-099-ILZ025-026-034-035-MOZ009-010-120000- Jefferson-Henry IA-Des Moines-Van Buren-Lee-Henderson-Warren- Hancock-McDonough-Scotland-Clark- Including the cities of Fairfield, Mount Pleasant, Burlington, Keosauqua, Fort Madison, Oquawka, Monmouth, Carthage, Macomb, Memphis, and Kahoka 1133 AM CST Mon Dec 11 2017 ...Gusty Winds Through the Afternoon... The winds will become northwest and gusty behind a passing cold front into this afternoon. The winds will be sustained at 20 to 30 mph with gusts up to 40 mph at times through this evening. Area travelers should be aware of the brisk winds and brief stronger gusts which may result in difficult driving conditions for short periods of time, especially for high profile vehicles. Lightweight and unsecured objects, such as holiday decorations, may also be blown around this afternoon. 12
The national radar mosaic for the moment the first event began.
4 winter weather. Local standard time, as filed.
Snowfall reports ranged from 1 inch at Galena to 4 inches 7 miles south at Stockton.
Trained spotter snowfall reports ranged from 3 inches at Lanark to 5 inches at Mount Carroll.
Snowfall reports ranged from 1.8 inches near Rock falls to 2.4 inches near Sterling.
Snowfall reports ranged from 1.0 to 2.3 inches across the county.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2017Every state in 2017This day in weather historyWarnings in Illinois, December 2017
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: 730650, 730649, 730652, 730651.