Tornado Drought in Illinois

One of the notable climate/weather stories in Illinois this year is the tornado drought. As of September 9, the NWS has received only 20 reports for Illinois (first map). The map of  Illinois includes all severe weather including tornadoes (20), hail (93), and wind damage (395). The last tornado reported in Illinois was on September 1, 2013, in LaSalle County. The report of that event is here.

The second map shows where the tornado reports were located across the US. It’s not just Illinois. Tornado reports in neighboring states were sparse as well.

The third figures shows the running annual count of tornadoes for this year and earlier years since 2005 in the United States, according to the Storm Prediction Center. At this point in time, this year has the lowest total of any year since 2005 with 725 tornado reports. 

Why are the tornado numbers so low this year in Illinois? Here the spring was dominated by large, slow-moving systems that produced lots of rain but not much severe weather. Then, starting in July, we transitioned into drought conditions with little opportunity for any severe weather.

The last graph shows the historical distribution of Illinois tornadoes by month. April, May, and June are the prime months – followed by March, July, and August. Therefore, the busiest months of the tornado season have past. We generally see a few tornadoes in the fall months but not like we do in spring or summer.

The NWS Storm Prediction Center has a wonderful web site full of severe weather statistics with maps and plots at http://www.spc.noaa.gov/climo/online/

IL_statemap

Red dotes are tornado reports (20), green dots are hail reports (93) and blue dots are wind damage reports (395). Source NWS Storm Prediction Center. Click to enlarge.

2013_annual_map_torn

Tornado reports for the US so far in 2013 (725). Source NWS Climate Prediction Center. Click to enlarge.

torngraph-big

Running annual count of tornadoes for this year (black line) compared to other years since 2005. Click to enlarge.

tornado-month

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About Jim Angel

I have been the state climatologist for Illinois since 1997 and have worked at the Illinois State Water Survey since 1984.
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One Response to Tornado Drought in Illinois

  1. Tornadoes are phenomena of care may seem initially but cause major disasters can.

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