Extreme heat and dryness will continue to deteriorate corn and soybean crops in much of the U.S. Midwest over at least the next week, with only minor amounts of rain seen for drought-plagued Indiana and Ohio, an agricultural meteorologist predicted Friday.

"It's a little wetter forecast for the eastern Midwest over the next 10 days, but only 0.10 to 0.25 inch daily, which won't help much," said Don Keeney, meteorologist for MDA EarthSat Weather.

The mercury will again hit the triple digits.

"High temperatures in St. Louis, Missouri will reach 104 to 106 degrees Fahrenheit today through the weekend, with 99 degrees early next week but back above 100 F by next Wednesday," he predicted.

No significant rainfall was expected elsewhere in the Midwest for at least the next 10 days, Keeney said.

Commodity Weather Group on Friday said heat would stress the western two-thirds of the Midwest and hamper corn pollination next week. Heat and dryness in the Delta was threatening early pod setting of soybeans. A break in the heat was expected in the next 11 to 15 days, but rains were still likely to be limited, according to CWG.

The lingering dryness and this week's turn to extreme heat was harming the corn and soybean crops, especially corn which was entering its critical pollination or reproductive stage of development.

The U.S. Department of Agriculture 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 under a baking sun 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 the drought and heat.

Analysts were scaling back their estimates for this year's domestic corn production as drought lingered.

(Reporting By Sam Nelson; Editing by John Picinich)