WEST LAFAYETTE, Ind. - While a major weather pattern change that brought much-needed rain and cooler temperatures to the parched eastern Corn Belt is welcome relief, Purdue University climatologists warn against thinking the drought is almost over.
The U.S. Department of Agriculture’s Drought Monitor (http://www.droughtmonitor.unl.edu) update on Thursday (Aug. 16) shows a shrinking area of exceptional drought - the worst drought rating available - that has gripped southwest and west-central Indiana. The southern half of the state is still largely encompassed by extreme to exceptional drought, but the northern half of the state mostly ranges from the lesser categories of moderate to severe.
The hot dome of high pressure that had been parked over Indiana and the Midwest much of the summer has shifted to the southwestern states, taking the excessive heat west with it, said Ken Scheeringa, associate state climatologist for the Indiana State Climate Office at Purdue (http://www.iclimate.org).
"This shift has allowed the jet stream, which was stuck far north of Indiana earlier this summer, to sink farther south, putting much of the state right into the storm track," Scheeringa said. "This change has given us better opportunities for more frequent and heavier rainfall with greater area coverage."
A few weeks ago, climatologists were expecting more of the same - a warmer-than-normal August with little rain. But recent shifts in the storm track driven by the jet stream and large-scale movement of the high-pressure system have changed that thinking.
"We will continue to evaluate our outlook for August," Scheeringa said. "In particular, if this pattern continues, it would be possible for August to end up with normal to cooler temperatures and about normal rainfall. As of today, August is near normal in temperature and above normal in rainfall. We will see what happens in the next two weeks."
While all of this certainly helps reduce drought conditions, Indiana State Climatologist Dev Niyogi cautions against thinking that Indiana’s drought is over.
"When folks see that the grass has greened up, the tendency is to think the drought is nearly over," he said. "But drought is more than lack of rainfall. It is a delicate balance between supply and demand. We need to consider the water status of deep wells, reservoirs and streams, many of which are depleted and will take a while to recover.
"The fact is there is still a large unmet demand and many regions with rainfall deficit. The Drought Monitor likely will continue to show drought for a while, but should continue to show slow improvement."
Purdue Extension has compiled a series of drought resources at http://www.purdue.edu/drought.