The statewide precipitation for June is 6.6 inches, 2.5 inches above the 1971-2000 average (normal). That makes it the ninth wettest June on record (based on preliminary numbers as of June 28, 2011).
The statewide precipitation for the first six months of 2011 is 27.2 inches, 7.7 inches above the 1971-2000 average. That makes it the fourth wettest January-June on record. Statewide records go back to 1895.
The figure below shows the June departure from normal precipitation across the US. Cool coolers (green, blue, purple) show abnormally wet conditions. Warm colors show abnormally dry conditions. Wet conditions have prevailed from Montana, into the Dakotas, Nebraska, Iowa, northeastern Missouri, across Illinois, and much of the lower Ohio River valley. However, dry conditions are not far from Illinois borders, especially to our southwest.
The figure below shows the year-to-date departure from normal precipitation across the US. Like June, the band of above-normal precipitation extends from Montana, down the Missouri River, and up the Ohio River valleys. This area has seen abundant atmospheric moisture and a strong, persistent jet stream for much of winter and spring. Meanwhile, the Southwest and South have struggled with dry conditions. BTW, it is not unusual to have one part of the US experiencing drought while another part experiences heavy rains and flooding. It is amazing that you can go from southern Illinois with its 8 to 16 inches of above normal precipitation to Arkansas and Mississippi and find areas that are 8 to 16 inches below normal on precipitation.
Illinois Agricultural Disaster Declaration Due to Drought
Press release on disaster declaration
On January 26, 2011, the USDA granted the Illinois Department of Agriculture’s request for federal disaster assistance for southern Illinois farmers who suffered crop losses caused by drought in 2010. The 16 counties are for the most part south of Interstate 64. The full press release can be seen here.
What happened
Rainfall amounts in parts of southern Illinois were much below normal from May all the way through October. However, the pattern and sequence of rain events varied from month to month and place to place. Therefore it’s hard to make a general statement about all the counties in the declared region. For example, Cairo IL received 28.6″ of rain from April to September (over 6 inches above normal) while Fairfield received only 17.1 inches (over 6 inches below normal).
Two contributing factors to crop losses are the regions shallow soils that hold less water and temperatures that were about 3 degrees above normal.
Here are two maps that show the percent of normal precipitation for the period of April-June 2010 and July-September 2010. As a rule of thumb, any 3-month rainfall totals less than 70% of normal is cause for concern. Click maps to enlarge.
