drought – Page 2 – Illinois State Climatologist

May 1, 2013

April 4th Wettest On Record

Precipitation

This April was the 4th wettest on record for Illinois with 6.90 inches, based on the preliminary numbers. That was 3.13 inches above the long-term average of 3.77 inches.
To show you how wet it was, this April easily beat out the combined statewide rainfall totals for Illinois in May, June, and July of 2012 during the worst of the drought. The total rainfall for those months in 2012 were 2.50 inches, 1.80 inches, 1.48 inches, respectively, which led to a total of only 5.78 inches. That was 1.12 inches less than this April!
The first map below shows the spectacular rainfall totals across much of the state. The areas in yellow and orange were 6 to 9 inches. A few areas in pink and red were 9 to 11 inches. This product has a 4 kilometer resolution and is based on radar estimates calibrated with rain gauges.
The second map shows the same rainfall amounts expressed as a percentage of the long-term average. There was a small patch of below-average rainfall in far southern Illinois. Otherwise the rainfall across the rest of the state was much above average. Many areas in the dark blue were 2 to 3 times their long-average rainfall.
Speaking of rain gauges, the two largest monthly totals for April so far were Augusta with 12.28 inches and Naperville with 11.03 inches. Several more stations reported totals in the 10-inch range.
There were two major impacts of the wet April. One was widespread flooding on the Illinois, Wabash, and Mississippi Rivers and their tributaries. Several sites along the Illinois reported record high river crests in April. Because the flooding included the Chicago area, the dollar damages and number of people affected will be quite large.
The second impact of the wet April was the delay in fieldwork. In the April 29 USDA NASS report, only 1 percent of the corn crop was planted, compared to 76 percent last April, and a five-year average of 36 percent.

Temperature

The statewide average temperature was 50.1 degrees and 2.3 degrees below average. That was not record-setting but reflects the fact that we had a lot of cool, cloudy days in April.

Figures

The April 2013 precipitation, ending with reports on the morning of May 1. Click to enlarge. — April 2013 precipitation, ending with reports on the morning of May 1. Click to enlarge.

April precipitation, expressed as a percent of the long-term average. Click to enlarge. — April precipitation, expressed as a percent of the long-term average, for reports ending on the morning of May 1. Click to enlarge.

April 8, 2013

Trouble Continues on the Missouri River

The US Corps of Engineers put out a press release today on the continued problems on the Missouri River due to the drought. From the release,

Based on the current soil moisture and snowpack conditions, 2013 runoff in the Missouri River basin above Sioux City, Iowa is forecast to be 20.5 million acre feet, 81 percent of normal. Runoff for the month of March was 55 percent of normal.

Full press release
At this time, 75 percent of the Missouri River Basin is in some stage of drought according to the US Drought Monitor. In addition 52 percent of the Upper Mississippi River Basin (above St. Louis) is in drought. See map below. Closer to home, recent rains and melted snow have kept the Mississippi River on the western boundary of Illinois in good shape this spring.

February 25, 2013

The Tale of Two Winters – One Dry, One Wet

We have had a remarkable contrast in the last two winters in terms of precipitation. While both winters have been relatively quiet in terms of snow (at least up until the last week), this winter has made up for it in rainfall.
Here are the January 1 to February 25 precipitation departure maps for 2012 (first figure) and 2013 (second figure) for the Midwest. Precipitation is the combination of rainfall and the water content of any snow/sleet/freezing rain events.
Areas in shades of yellow show below-average precipitation while areas in shades of green show above-average precipitation. As you can see, the widespread yellow in 2012 was replaced with widespread green in 2013. This is good news for Illinois and for the Midwest.

February 21, 2013

New Climate Prediction Center Outlooks

On February 20, the NWS Climate Prediction Center released their new outlooks for March and beyond. Below are the maps for March, spring (March to May), and summer (June to August).
The overall theme for Illinois is an increased chance of above-average temperatures through August. We have an increased chance of above-average precipitation in the March-May period, followed by equal chances in the June-August period. If it pans out, above-average precipitation for this spring should help with low water levels on both the Great Lakes and Mississippi River as well as alleviate drought concerns in northern Illinois.
If you are wondering when was the last time we had a spring that was both warmer and wetter than average, you do not have to look very far. The springs of 2004, 2006, 2009, 2010, and 2011 all qualified as having both above average on precipitation and temperature. In fact, our spring temperatures in Illinois have been at or above average in all but 2 years since 1998 (last figure).

The Climate Prediction Center outlook for March and March-May. NOAA.

Climate Prediction Center outlook for summer (June-August). — Climate Prediction Center temperature outlook for summer (June-August).

Climate Prediction Center precipitation outlook for summer (June-August).

Spring Temperatures in Illinois since 1895. Source: http://www.southernclimate.org/products/trends.php — Spring Temperatures in Illinois since 1895. The green dots are the spring temperatures each year. The shaded curve represents a 5-year running average with extended periods of cool temperatures shaded in blue and extended periods of warm temperatures shaded in red. Source: http://www.southernclimate.org/products/trends.php