By Carey Gillam
KANSAS CITY, Missouri (Reuters) - Rainfall and cooler temperatures have combined to ease slightly the grip that the worst U.S. drought in over five decades is holding on some key farming states, but the suffering expanded in many others.
"There has been some improvement, at least in the eastern corn belt. And for the region as a whole we've seen a respite from the high temperatures," said Mark Svoboda, a climatologist with the University of Nebraska's National Drought Mitigation Center.
But he said the forecast for the next few weeks showed a return to harsh conditions.
"It's unfortunately looking like a return to above-normal temperatures and below-normal precipitation," he said. "It's not enough to start thinking this drought is going to be over anytime soon."
The portion of the contiguous United States suffering from at least "severe" drought fell to 44.03 percent from 45.54 percent over the last week, according to the Drought Monitor, a weekly synthesis representing a consensus of federal and academic scientists.
The area experiencing "extreme" levels of drought dropped to 23.01 percent from 23.68 percent, while the worst level of drought, exceptional, ticked up to 6.31 percent from 6.26 percent.
Indiana had a notable improvement in conditions, with extreme drought levels dropping to 37.09 percent of the state from 46.30 percent. The worst level - exceptional drought - fell to 10.77 percent of the state from 16.63 percent.
Illinois also saw relief, as the areas in a combination of extreme and exceptional drought dropped to 76.72 percent from 79.54 percent.
Arkansas had significant improvement, as exceptional drought eased to 45.30 percent of the state from 53.60 percent the prior week and extreme drought dropped to 74.38 percent from 80.93 percent.
Conditions worsened in Texas, Missouri and Iowa. The area of Missouri in extreme and exceptional drought conditions expanded to 99.29 percent from 94.68 percent. In Iowa, extreme drought grew to 67.54 percent of the state from 62.05 percent.
Oklahoma worsened significantly as well, with 48.10 percent of the farm state now in exceptional drought, from 38.86 percent a week earlier.
In the High Plains, a six-state region that includes Kansas, Nebraska and Colorado, the combined level of extreme and exceptional drought expanded to 51.72 percent from 49.64 percent, according to the Drought Monitor.
Persistent high heat and lack of soil moisture have decimated the U.S. corn crop, and threaten the same to the soybean crop.
The Drought Monitor report said that last week, drought gripped slightly less of the agricultural land in the country, affecting 85 percent of the U.S. corn crop, 83 percent of soybeans, 63 percent of hay, and 71 percent of cattle areas.
Some 49 percent of the corn area and 46 percent of the soybean areas were experiencing extreme to exceptional drought.
Ranchers have been forced to liquidate herds as they struggle to keep their animals fed and watered; wildfires have burned through thousands of acres, and waterways have become unusable in some areas.
Water levels on the Mississippi River dropped so low in the last week that barges have run aground, slowing the movement of grain and other goods.
California Governor Jerry Brown declared a state of emergency in three northern California counties on Wednesday due to wildfires.
(Editing by Dale Hudson)