A strong cold front passage on November 19th ushered in the coldest air of the season and set the stage not just for the first Midwest snowfall on the 20 - 21st but also one of the most historic November storms on record! The storm left a 300 mile wide swath of snow across Iowa, northern Illinois, Indiana and northwest Ohio in its wake, as shown in the visible satellite image, and smashed records in nearly all categories.
The historic storm arrived during the evening of the 20th with intense bands quickly developing across northern Illinois near the Wisconsin border, dumping as much as 1 – 3" of snow per hour! These areas took top honors for the highest snow amounts as totals reached 15 – 18 inches! Thanks to northeast winds off Lake Michigan moderating temperatures in Chicago metro, a sharp snowfall gradient as high as 10 inches over just 15 miles straddled Cook County. As the storm departed on the 21st, strong winds followed, gusting up to 35 – 40mph with temperatures quickly tumbling into the single digits!
Needless to say, the storm crushed plenty of snowfall records. Besides being the second highest November snow event ever on record for both the Chicago O’Hare and Chicago Rockford airports, the 11.2” at O’Hare tops the chart for the highest first snow event of all-time. Interestingly, it took until January last winter for O’Hare’s seasonal total to reach over 11 inches and it did not record any double digit snow events until February!
In addition, the event also broke daily snowfall records at both airports. Chicago O’Hare’s 4.2” on November 20th surpassed the previous daily record of 2.8” set in 1996 and Rockford’s 4.9” crushed the previous 2.4” daily record set in 1964. November 21st followed suit with even higher amounts. The 7.0” at Chicago O’Hare bested the previous daily record of 3.0” set way back in 1893 and Chicago Rockford’s 3.9” amount ousted the daily record of 1.0” set in 1989.
Due to this incredible snow event, November 2015 ranks among the top ten snowiest Novembers on record for both airports with a November snowfall departure of 10" above normal at O’Hare and 7.1" at Rockford. Will we see similar events in December? Find out more in our December outlook.
