Stifling heat and bone dry weather will persist in the U.S. Midwest for at least the next 10 days, further stressing already hurting corn and soybean crops, an agricultural meteorologist predicted Thursday.

"Nothing has changed. We're still looking at pronounced dryness for the next 10 days," said John Dee of Global Weather Monitoring.

Temperatures will soar to the upper 90s and triple digits degrees Fahrenheit Thursday. And the mercury will stay in the 90s for the next week or two.

"There will be a few scattered showers in the north, but only 0.20 to 0.60 inch, and it looks like 30 percent of the Midwest will stay completely dry," Dee said. "Bottom line is ... more pressure on crops for the next 10 days."

The lingering dryness and current turn to extreme heat are harming the corn and soybean crops, especially corn which is entering its critical pollination or reproductive stage of development.

The USDA on Monday said 56 percent of the domestic corn crop was in good-to-excellent condition, down 7 percentage points from the previous week.

Soybean conditions declined as well, and crop experts expected further deterioration this week because of extreme dryness in roughly the southern half of the Midwest. And the incoming heat wave will speed crop losses.

Chicago Board of Trade new-crop December corn futures have soared nearly 30 percent or $1.50 per bushel since the middle of June because of the prospect for crop losses due to drought and heat.

Analysts scaled back their estimates for this year's corn production. Commodity Weather Group on Thursday said the heat stress could continue in the southwestern part of the Midwest for the next 10 days. The pod-setting of soybeans in the lush Delta was now being threatened as well. Pod-setting is the critical yield-determining stage of development for the soybean plant.

(Reporting By Sam Nelson; Editing by John Picinich)