Two Tornadoes and other Severe Weather in Illinois over the Weekend

Severe weather, including tornadoes, heavy rains, high winds, hail, and flooding occurred across parts of Illinois yesterday and last night.

Here is the radar estimated precipitation with areas in green indicating 1 to 2.5 inches an areas in yellow and orange indicating 2.5 to 4 inches.


Below are reports of storm damage across the US for the 24 hours ending on the morning of June 8, 2015. The two tornadoes in Illinois occurred near Petersburg and Seymour. Neither one cause much damage and no injuries. There were a few reports of 1-inch hail and many reports of wind damage in Illinois from these storms. Data obtained from the NOAA Storm Prediction Center storm damage page. Continue reading

Hail in Champaign-Urbana

Here is a shot of the hail dents on our hailpad at the Illinois State Water Survey in Champaign from this morning’s storm. Most of the dents where in the 1/4 to 1/2 inch range.

To construct a hailpad, we use sections of flourist or floral foam covered with aluminum foil. It is low tech but an excellent way to record hail sizes and density, especially when no one is around.


May in Illinois: Warmer Than Average, Dry in the West


Based on preliminary data, the statewide average temperature for May in Illinois was 63.9 degrees. That is 1.2 degrees above average and the first month to be above average in Illinois since October 2013.


The statewide average precipitation for May in Illinois was 4.26 inches, just 0.34 inches below average. Below is a map of precipitation throughout the state. This is a radar-based product that is adjusted with rain gauges, resulting in higher resolution than a rain gauge network and more accuracy than a radar-only precipitation measurement. Sometimes hail can mislead the radar into calculating higher rainfall rates. That may have been the case in southern Champaign County, for example.

Some of the heaviest rainfall totals from the CoCoRaHS network for May occurred in Cook County, including Burnham-Hegewisch (IL-CK-82) with 7.64 inches and Homewood (IL-CK-64) with 7.58 inches.

The area of concern for May was the large section of blue across western and central Illinois, representing rainfall totals of only 1 to 3 inches. There are some smaller patches of blue in southern Illinois and far northwestern Illinois as well. One of the drier locations in west-central Illinois was Roseville (IL-WR-2) with only 1.32 inches with all 31 days reported. The US Drought Monitor list parts of western Illinois as “abnormally dry”.



Plots of Temperature and Precipitation

Here are the time series plots for temperature and precipitation departures for each month of 2013 and 2014. In the first plot, one can clearly see the string of very cold months from November 2013 to April 2014. On the second plot, the dryness of late last summer shows up. While March of this year was dry, it was counterbalanced by a wetter than average April.



Storm Damage and Goss’s Wilt in Corn Crop

The University of Illinois blog “the Bulletin” has an article on the development of Goss’s Wilt in corn after storm damage¬†(high winds and/or hail).

Sometimes you may not notice the initial damage and want to figure out when it occurred. There are a few sources out there for doing this.

One way is to look at the storm damage reports from the Storm Prediction Center. Each day they report damaging winds, hail, and tornado damage across the US. Just click on the map for “today” and across the top there are links to go back and forth.

Another source for wind data is the nearby airport. Almost every airport with commercial traffic has an automated weather station on site. You can find the nearest airport data by going to and ask for the forecast for your site. If you ask for more details, you will eventually see data from the nearby airport including the history of the last 3 days.

Finally, the Illinois State Water Survey operates 19 sites around the state that collect wind data along with soil temperatures, solar radiation, etc. You can view that information here.

There is some information on the hail climatology of Illinois and the US. I posted a few resources on my web page on hail. One of the world’s leading experts on hail, Stan Changnon, worked at the Water Survey and wrote a considerable amount on the subject.

Severe Weather in Illinois for 2011

According to statistics compiled by NOAA’s Storm Prediction Center, so far in 2011 Illinois has had 58 reports of tornadoes, 298 reports of significant hail (1 inch or more), and 674 reports of wind damage. That’s about average for us. Fortunately, we escaped the worst of the 2011 season that centered on the southeastern U.S. and Joplin, MO.

See the first figure below for the distribution of events. In some cases, we may have multiple tornado reports from the same tornado as it travels along.

The second figure shows the distribution of severe weather reports by month for Illinois. After a quiet start to 2011, severe weather activity picked up in April and continued through July before tapering off in August and September. You can see the monthly raw data and chart in Google Docs.

Severe weather reports for 2011. Red dots are tornadoes, green dots are hail, and blue dots are wind damage. Click to enlarge.