* Corn and soy slip on non-threatening U.S. weather

* Wheat falls on soft demand

CHICAGO, Aug 1 (Reuters) -

U.S. corn and soybean futures fell to their lowest levels in nearly four years on Thursday as forecasts for cool, rainy weather in the Corn Belt boosted yield expectations and depressed prices, analysts said.

Meanwhile, wheat futures rose on global weather concerns during a choppy trade.

The most-active corn contract on the Chicago Board of Trade was down 1-3/4 cents at $3.98 a bushel by 11:13 a.m. CDT (1613 GMT) after dipping to $3.95, its lowest level on a continuous chart since November 2020.

"It's mostly weather and the idea that we're looking at major yields coming up this year," Jack Scoville, vice president at Price Futures Group, said as he described corn's downward spiral.

Dealers said U.S. farmers have begun selling corn stored from the 2023 harvest as the chance of higher prices recedes and they seek to make room for the coming crop.

CBOT soybeans fell 6-1/2 cents to $10.16 a bushel after touching $10.13, the lowest for a most-active soy contract since October 2020.

"With soy products not moving, it's going to be hard for the market to get any traction," Matthew Wiegand, consultant at Futures One, said.

Traders shrugged off the U.S. Department of Agriculture's confirmation of

private sales

of 132,000 metric tons of new-crop U.S. soybeans to China, the first sales announcement to the world's top soy buyer in three weeks.

The wheat market continued to keep a close watch on weather concerns in western Europe while monitoring the wheat harvest in the previously drought-stricken Black Sea region.

CBOT wheat gained 2-1/4 cents to $5.29-1/2 a bushel.

Storms and forecasts of more showers could halt the French wheat harvest again after farmers made progress during a hot spell early this week.

However, weak demand for U.S. wheat is likely to cap any gains, traders said.

"We have worries about French, Ukrainian and Russian wheat, but until demand comes to U.S. wheat it's going to be slow," Scoville said. (Reporting by Heather Schlitz in Chicago. Additional reporting by Nigel Hunt in London and Mei Mei Chu in Beijing Editing by David Goodman and Marguerita Choy)