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.

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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.

hail-april8-2015

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

Temperature

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.

Precipitation

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”.

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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.

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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 weather.gov 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.

Severe Weather in Illinois in 2011

According to preliminary data from the NOAA Storm Prediction Center (SPC), in 2011 Illinois has received:

  • 55 reports of tornadoes
  • 247 reports of hail greater than 1 inch in diameter
  • 474 reports of wind damage

So it has been a fairly active year for severe weather in Illinois. Fortunately, we have not experienced the level of devastation as was seen in the Southeast or in Joplin, MO.

Personally, the outstanding feature of this year is hail. I’ve had pea-sized hail at my house four times this year (including last night at around 1 am). That’s unusual for me because I’ve gone for years at a time without seeing any hail at home. Out of curiosity, I pulled up the hail statistics since 2000 for Illinois from the SPC site. Beginning in 2011, they changed the significant hail criteria from three-quarter inch to one inch so any hail report less than one inch will no longer be counted.

  • 247 in 2011, as of June 27, 2011
  • 120 in 2010
  • 245 in 2009
  • 502 in 2008
  • 252 in 2007
  • 906 in 2006 (also a big year for tornadoes)
  • 339 in 2005
  • 383 in 2004
  • 588 in 2003
  • 256 in 2002
  • 193 in 2001
  • 342 in 2000

Severe Weather On April 19, 2011

Thunderstorms moved across Illinois on Tuesday, April 19, 2011, causing widespread damage from tornadoes, hail, and high winds. See map below. In Illinois alone, there were 15 reports of tornadoes – six in Macoupin County, six in Montgomery County, two in Christian County, and one in Vermilion County.

Hail amounts up to 2.75 inches in diameter were reported as well. The 2.75 inch hail fell in Roodhouse in Green County, followed closely in size by 2.5 inch hail in Golden Eagle in Calhoun County. A complete list of storm reports for April 19 is found at the Storm Prediction Center page for April 19.

The NWS is now conducting damage surveys:

[April 21: I added a map of SPC storm reports for the Midwest.]

Map of severe weather reports for the Midwest for April 19, 2011. The data are from the Storm Prediction Center and the map was created by Zoe Zaloudek.
NOAAs Storm Prediction Center reports on April 19, 2011.