Drought Eases In Illinois

The U.S. Drought Monitor has reduced the area in drought for Illinois (first map below). Generous rainfall in recent weeks (second map) along the northern and southern borders of the drought led to the reductions. It also helps that cooler temperatures and maturing field crops have reduced the demand on soil moisture.
Soil moisture measurements from a network of sites operated by the Illinois State Water Survey confirmed that soil moisture was recovering by September 28. The table below list the soil moisture at 2, 4, and 8 inches and are a percentage of the water by volume. For example, “24” at 2 inches in Belleville means that the water content of the soil at that point is 24 percent. For most soils in Illinois, values of 30 percent or more mean plenty of soil moisture, values in the 20 percent range are a little dry, and values in the 10 percent range are very dry. The very low values at Kilbourne are typical of the very sandy soil there. They tend to drain very quickly and are only high right after a significant rainfall events.

Location	2 in	4 in	8 in
Belleville      24      28	27
Big Bend	24	29	23
Bondville	17	17	33
Brownstown	24	22	23
Champaign	21	31	32
Carbondale	28	34	32
DeKalb	        38	37	38
Dixon Springs	33	36	38
Fairfield	37	34	35
Freeport	36	37	42
Kilbourne	3	4	3
Monmouth	24	30	24
Olney	        26	30	32
Peoria	        32	35	35
Perry	        17	15	18
Springfield	25	23	14
Stelle	        32	34	29
St. Charles	33	38	39
Rend Lake	26	39	40

drought monitor
U.S. Drought Monitor results for Illinois, September 27, 2011.

september rainfall
September 1-28, 2011, rainfall for Illinois.

2011: A Year of Extremes

I think we will remember 2011 as a year of extreme events. In Illinois we have already faced a February blizzard, flooding, record rainfalls, drought, and a heat wave.  The latest newsletter of the NOAA’s Regional Climate Centers Program has highlighted several major events from around the country, including:

  • wildfires
  • tornadoes
  • spring flooding in the Midwest
  • record flooding in the Missouri River Basin
  • drought
  • snow

Check it out. I don’t know about anyone else but I’m ready for a quiet fall.
BTW, the Midwestern Regional Climate Center is housed at the Illinois State Water Survey.

August – Drought in Central Illinois

The statewide average precipitation was 2.06 inches, 1.6 inches below average and 56 percent of average. This was the 13th driest August on record since 1895, based on preliminary data.
The driest area was south of and parallel to Interstate 74 (Figure 1). Rainfall amounts in that region were generally an inch or less. One of the driest spots in Illinois was Lovington (Moultrie County in east-central Illinois) with only 0.03 inches for the entire month. Other familiar sites with extremely low readings included: Decatur with 0.15 inches, Springfield with 0.25 inches, and Quincy with 0.25 inches.
Only northern Illinois received average to above-average rainfall in August (Figure 2). One of the wettest spots in Illinois was Morris (Grundy County) with 7.02 inches, followed closely by Earlville (LaSalle County) with 7.01 inches.
Moderate to severe agricultural drought arrived in Illinois in August (Figure 3), according to the US Drought Monitor. This was the result of much less than average rainfall in July and August, as well as warmer than average temperatures. Damage to corn and soybean crops appears to be significant in places. However, the full extent of the damage will not be known until harvest.
Temperatures were above average for much of Illinois (Figure 4). Highs in the 90s and even low 100s were common across the state. The hottest spots in the state were Cairo with 103 degrees on August 4 and Bentley with 103 degrees on August 25. Both Quincy and Grand Chain Dam were close with 102 degrees on August 2 and August 4 respectively.
The statewide mean temperature (an average of both the high and low temperatures) was 74.9 degrees, 1.2 degrees above average.

August 2011 precipitation
Figure 1. August 2011 precipitation for Illinois. Click to enlarge.

August 2011 precipitation departure
Figure 2. August 2011 precipitation departure for Illinois. Click to enlarge.

drought monitor
Figure 3. US Drought Monitor for August 30 2011 for Illinois. Click to enlarge.

Figure 4. Temperature departures for August 2011 in Illinois. Click to enlarge.