February 18, 2022: Snow Squall Impacts Far Northern and North Central Illinois

Webcam

Snow squall observed by the NWS Chicago Doppler Radar from 7:50 P.M.-10:50 P.M.

WIFR webcam image of State Street in Rockford during the peak of the snow squall (note there was no snow on the ground just ~10 mins prior to this image).

Fast Facts
Storm Reports
Maximum Winds
Science
Photos & Links

Fast Facts

A snow squall moved across portions of the Upper Midwest, including Wisconsin, northeast Iowa, and parts of northern Illinois, from mid-afternoon into evening of Friday, February 18, with the most intense rates and wind, including with lightning, mainly occurring in Wisconsin.

The definition of a snow squall is an intense but limited duration period of heavy snowfall accompanied by strong, gusty surface winds. This event absolutely lived up to that, with near zero to zero visibility under the most intense area of the squall with rapidly accumulating snow.

The potential for snow squalls was noted already the day before and especially the morning of. Here is a Key Messages graphic from the NWS Weather Prediction Center highlighting this, which was done in collaboration with local NWS offices.

National Key Messages

The snow squall moved over Rockford, producing 1.2" in about 30 minutes at the Chicago Rockford International Airport, and near zero visibility due to winds also gusting over 50 mph (the airport measured 53 mph).

As the squall moved east-southeast through northern Illinois, it began to weaken. The far northern and western Chicago suburbs did experience some of the squall before this occurred.

NWS offices covering this portion of the Midwest had highlighted the snow squall potential early that day, and then issued Snow Squall Warnings as the squall became defined. A reminder that Snow Squall Warnings alert Wireless Emergency Alerts (WEAs) on smartphones, apart from between 10 PM and 6 AM, and are geared to inform motorists or those about to travel of the impending danger.

More on Snow Squall Warnings


Snow Squall Warning issued at 7:46 P.M.	Snow Squall Warning issued at 8:42 P.M.


Snow Squall Warning issued at 9:30 P.M.	Snow Squall Warning issued at 10:05 P.M.

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Storm Reports

PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE CHICAGO IL
431 AM CST SAT FEB 19 2022

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0841 PM     HEAVY SNOW       SOUTH BELOIT            42.49N 89.04W
02/18/2022  U0.0 INCH        WINNEBAGO          IL   TRAINED SPOTTER

            SNOW SQUALL. VISIBILITY LESS THAN A COUPLE
            HUNDRED FEET IN HEAVY SNOW.

0854 PM     HEAVY SNOW       ROCKFORD AIRPORT        42.20N 89.10W
02/18/2022  M1.2 INCH        WINNEBAGO          IL   OFFICIAL NWS OBS

            SNOW SQUALL. PEAK OBSERVED WIND OF 53 MPH.
            TOTAL SNOWFALL, MOST OBSERVED WITHIN A HALF
            HOUR SPAN FROM 8:35 TO 9:05 P.M.

0948 PM     HEAVY SNOW       2 S DEKALB              41.90N 88.75W
02/18/2022  U0.0 INCH        DE KALB            IL   TRAINED SPOTTER

            SNOW SQUALL. REPORTED FROM WITHIN AND NEAR
            DEKALB BY MULTIPLE SPOTTERS. THE DEKALB
            AIRPORT AWOS ALSO CONFIRMED QUARTER MILE
            VISIBILITY AND GUSTS TO 40 MPH.

0950 PM     HEAVY SNOW       CARY                    42.21N 88.24W
02/18/2022  U0.0 INCH        MCHENRY            IL   TRAINED SPOTTER

            SNOW SQUALL. VISIBILITY UNDER 200 FT
            REPORTED.

1017 PM     HEAVY SNOW       DUPAGE AIRPORT          41.91N 88.25W
02/18/2022  U0.0 INCH        DUPAGE             IL   ASOS

            SNOW SQUALL. GUST TO 43 MPH. NEARBY PUBLIC
            REPORT OF VISIBILITY OF ONLY A FEW HUNDRED
            FEET IN HEAVY SNOW.

Maximum Winds


Public Information Statement
National Weather Service Chicago IL
616 AM CST Sat Feb 19 2022 /716 AM EST Sat Feb 19 2022/

...HIGHEST OBSERVED WIND GUSTS FROM FRIDAY FEBRUARY 18...

Observations are collected from a variety of sources with varying
equipment and exposures. We thank all volunteer weather observers
for their dedication. Not all data listed are considered official.

FROM THE SNOW SQUALL PERIOD:

Land Location                Speed     Time/Date       Provider
---------------------------------------------------------------
Rockford Airport             53 MPH    0854 PM 02/18   ASOS
Sterling Airport             49 MPH    0926 PM 02/18   AWOS
Peru Airport                 48 MPH    1035 PM 02/18   AWOS
Sugar Grove - Aurora Arpt.   46 MPH    1108 PM 02/18   ASOS
Freeport Airport             44 MPH    0835 PM 02/18   AWOS
Waukegan Airport             43 MPH    0942 PM 02/18   ASOS
DuPage Airport               43 MPH    1017 PM 02/18   ASOS


FROM THE ENTIRE DAY AND NIGHT:

Land Location                Speed     Time/Date       Provider
---------------------------------------------------------------
Rockford Airport             55 MPH    1041 PM 02/18   ASOS
Herbert 5 ENE (McHenry DOT)  52 MPH    0820 PM 02/18   MESOWEST
1.7 E Remington (INDOT)      50 MPH    1047 PM 02/18   MESOWEST
Harvard 6 NW (UP Rail)       50 MPH    0802 PM 02/18   MESOWEST
Chicago Midway               49 MPH    1145 PM 02/18   ASOS
Waukegan Airport             49 MPH    0821 PM 02/18   ASOS
Harvard 4 NW (McHenry DOT)   48 MPH    0820 PM 02/18   MESOWEST
Peru Airport                 48 MPH    1035 PM 02/18   AWOS
Marengo 5 NW (McHenry DOT)   47 MPH    1030 PM 02/18   MESOWEST
Chicago O`Hare               47 MPH    1113 PM 02/18   ASOS
Sugar Grove - Aurora Arpt.   46 MPH    1108 PM 02/18   ASOS
West Chicago - DuPage Arpt.  46 MPH    1129 PM 02/18   ASOS
Gary Airport                 46 MPH    1235 AM 02/19   AWOS
Valparaiso Airport           46 MPH    0955 PM 02/18   ASOS
Wheeling - Chicago Exec. Arp 45 MPH    1131 PM 02/18   ASOS
Elmhurst (UP Rail)           45 MPH    1110 PM 02/18   MESOWEST
Geneva 3 W (UP Rail)         45 MPH    0955 PM 02/18   MESOWEST
Crown Point                  42 MPH    0959 PM 02/18   MESOWEST
Fowler                       41 MPH    0130 AM 02/19   MESOWEST
Kankakee Airport             41 MPH    1140 PM 02/18   AWOS
DeKalb Airport               40 MPH    0915 PM 02/18   AWOS
Crystal Lake (McHenry DOT)   39 MPH    0840 PM 02/18   MESOWEST
McHenry (McHenry DOT)        39 MPH    1030 PM 02/18   MESOWEST
2.7 W Collegeville (INDOT)   39 MPH    1239 AM 02/19   MESOWEST
1 N South Shore - Chicago    39 MPH    0800 PM 02/18   NDBC
Rensselaer Airport           39 MPH    1155 PM 02/18   AWOS
Schaumburg Airport           38 MPH    0715 PM 02/18   AWOS
Morris Airport               37 MPH    0135 AM 02/19   AWOS
Pontiac Airport              36 MPH    1115 PM 02/18   AWOS
Rochelle Airport             36 MPH    0235 PM 02/18   AWOS

Marine Location              Speed     Time/Date       Provider
---------------------------------------------------------------
Harrison-Dever Crib          54 MPH    0600 PM 02/18   NDBC
2 WNW Michigan City          52 MPH    1230 AM 02/19   NDBC
Cline Avenue Bridge          51 MPH    0830 PM 02/18   WXFLOW
Montrose Beach Light         46 MPH    1142 PM 02/18   WXFLOW
Waukegan Harbor              39 MPH    0900 PM 02/18   NDBC
Calumet Harbor               38 MPH    0618 PM 02/18   NOS-NWLON

Science

Regional Radar Loop

Science

Regional radar loop from the February 18 snow squall event, including cloud-to-ground lightning.

NWS infographics regarding the science behind snow squalls. The keys to remember are 1.) a strong cold front or upper disturbance, 2.) instability, and 3.) thermal profile within the clouds supporting efficient snowfall.

Aircraft Sounding

Aircraft observed sounding from Midway Airport shortly after the quickly decaying snow squall had moved through. This was as close proximity of an observed sounding from the region that we could locate. This shows the steep low-level lapse rates immediately along/behind the cold front, providing a source of instability, and strong unidirectional winds immediately behind the front. Note the favorable thermal profiles at the top of the mixed layer (top of the steep low-level lapse rates), which are in the dendritic growth zone of -12C to -18C.

Photos & Links

Photos


Franklin Grove, IL in northern Lee County during the snow squall. Photo courtesy of Sauk Valley Weather.	Webcam from between Zion and Waukegan in northeast Lake County, IL during the snow squall. Photo courtesy of Lake County Passage.

Links

Media use of NWS Web News Stories is encouraged!
Please acknowledge the NWS as the source of any news information accessed from this site.

Additional recaps can be found on the NWS Chicago Past Events Page.

Severe Weather and Flooding Threat in the Central U.S. and Mid-Atlantic; Dangerous Heat in the West and Southern Plains

February 18, 2022: Snow Squall Impacts Far Northern and North Central Illinois