Dryness Continues Across the Corn Belt

What a change in fortunes. After the wettest January-July on record in Illinois with 29 inches and 9.5 inches above average, we are now facing exceptionally dry conditions in the last 30-45 days across much of Illinois as well as the Corn Belt.

As the map of precipitation percent of average since July 1 shows, a large part of the Corn Belt is running at less than 50% (shaded dark orange to red).  Until recently we saw few impacts on crops because of cooler-than-average temperatures and the excess of soil moisture at the beginning of July. But all that is beginning to change. Warmer weather has returned this week and is expected to continue for at least the next 14 days, according to the NWS.

The soil moisture reports from the USDA NASS indicate that soil moisture is beginning to run low. Topsoil moisture a month ago was rated at 16 percent short and 0 percent very short. Monday’s report rated it at 50 percent short and 11 percent very short.

Subsoil moisture a month ago was rated at 9 percent short and 0 percent very short. Now it is rated at 35 percent short and 8 percent very short.

The Illinois State Water Survey reported lower soil moisture levels at their sites.

The one bright spot in the forecast is that there is a chance of rain in the next five days (second map). However, the potential amounts are modest. Northeast Illinois could see between 0.5 and 1.0 inches. The rest of the state is more likely to see 0.5 inches or less.  If the forecast holds, parts of Iowa, Minnesota, and Wisconsin could see some relief from the current dry conditions.

30-day precipitation percent of average for period ending August 21, 2013, based on radar and rain gauge data. Click to enlarge.
5-day potential precipitation amounts from the NWS, August 21, 2013. Click to enlarge.