DES MOINES, Iowa (AP) - The drought gripping much of the nation is expanding in both size and severity, the National Drought Mitigation Center at the University of Nebraska-Lincoln said last week.

The areas most affected by the drought stretch from Georgia to Arizona. But areas of severe drought are growing in the Upper Midwest. The hardest-hit spot covers central South Dakota and reaches into southern North Dakota, according to a drought map updated weekly by the center.

Two weeks ago, the drought map showed most of Iowa and Minnesota was abnormally dry and that moderate drought had developed in each state.

Last week, severe drought emerged in both.

"I don't like to see such a large area," said Harry Hillaker, state climatologist at the Iowa Department of Agriculture and Land Stewardship in Des Moines. "The bigger it is, the harder it is to get rid of. The weather tends to feed on itself in the summer."

Hillaker said that Iowa is about 3.42 inches short of its normal precipitation for Jan. 1 to July 21. South-central Iowa has been hit the worst by the lack of precipitation, as the area is 6.43 inches short of normal.

Central Iowa is 4.77 inches below normal, while west-central Iowa is 4.88 inches short. Monroe County in south-central Iowa has a 10.75-inch precipitation deficit, the worst in the state.

"They're going to need some rain real quick because they have no reserve left," Hillaker said.