precipitation

January 27, 2011

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.

AMJ10PNormMRCC — April-June, 2010, precipitation departures from normal.

JAS10PNormMRCC — July-September, 2010, precipitation departure from normal.

January 3, 2011

2010 Temperature and Precipitation in Illinois

Updated January 16 to include graph of monthly precipitation departures.

Temperature

Based on preliminary data, the statewide annual temperature for Illinois in 2010 was 52.8 degrees, 1 degree above normal. Even so, the winter months of January, February, and December were much below normal. See bar graph below.

The statewide annual precipitation for Illinois in 2010 was 40.32 inches, 1.09 inches above normal. This was far less than the 50.46 inches in 2008 and the 51.02 inches in 2009. Of course the precipitation in 2010 was not evenly distributed throughout the state. Western Illinois experienced much above normal rainfall with amounts in excess of 48 inches in some areas. Meanwhile southern Illinois struggled with drought through much of the summer and fall. Below are the maps of total precipitation and departures from normal.

The 2010 precipitation total for Illinois.

2010 precipitation departure for 2010 — The 2010 precipitation departure from normal for 2010.

December 1, 2010

Warm November in Illinois

November

The statewide average temperature for November 2010 was 43.4 degrees, which was 1.6 degrees above normal. That makes it the 26th warmest November since statewide records began in 1895.
By the way, the 2000’s are well represented in the list of warm Novembers. Their rank and year include: #1 (2001), #5 (2009), #10 (2004), #14 (2003), #16 (2005), and #17 (2006).
The statewide average precipitation for November was 3.2 inches, only 0.1 inches below normal. November was exceptionally dry until the long Thanksgiving weekend arrived. Rains from that period signaled the recovery of soil moisture around the state. See the earlier posts on this subject.
The highest monthly total precipitation in Illinois for November was 7.15 inches recorded at Mt Carmel. The highest daily temperature for November was 82 degrees recorded at Cairo on November 13. The lowest daily temperature for November was 12 degrees recorded at Mt Carroll on November 26.

Fall

The statewide average temperature for fall (September-November) was 55.4 degrees, 1.2 degrees above normal.
The statewide average precipitation for fall was 8.6 inches, 0.8 inches below normal. Widespread rains in early September and late November masked the long period in between with dry conditions.
Note: these numbers are preliminary and subject to change as more data arrives.

November 18, 2010

Updated Forecast for December and Winter

NOAA’s Climate Prediction Center has come out with a new forecast for December and for December-February (winter). This is part of their routine update cycle.

December

The outlook for December in Illinois calls for an increased chance of above normal temperatures. An increased chance of above normal temperatures translates into just a few degrees above normal. Temperatures in Illinois have run an average of 2.9 degrees above normal for every month since March of this year. Therefore, continuing with a forecast for above-normal temperatures is not surprising.
The outlook calls for equal chances of above, below, or near-normal precipitation (or equal chances as they call it) in December in Illinois.

December-February (winter)

The outlook for December-February remains the same as last month. There is an increased chance of above-normal precipitation for all of Illinois. And, there is an increased chance of above-normal temperatures for the southern two-thirds of the state. See the figure below for more details.

CPC forecast — NOAA's Climate Prediction Center forecast for December and December-February (click to enlarge).