CHICAGO, Oct 5 (Reuters) - U.S. soybean futures fell about 1% on Wednesday on macroeconomic worries while corn and wheat were mixed in choppy trade as the dollar bounced and brokers awaited more information on the size of the U.S. harvest, analysts said.

By 1:02 p.m. CDT (1802 GMT), Chicago Board of Trade November soybeans were down 12-1/2 cents at $13.71 per bushel, but stayed above the contract's two-month low set on Monday at $13.61-1/4.

CBOT December corn was up 3/4 cent at $6.83-3/4 a bushel and December wheat was unchanged at $9.03 a bushel in back-and-forth trade.

The dollar index rebounded as recent risk-on sentiment reversed and U.S. stocks dropped. A firmer dollar tends to make U.S. grains less attractive globally.

"The mood has switched more risk-off today with equities falling and a firm dollar unfavourable for U.S. export prospects," said Matt Ammermann, StoneX commodity risk manager.

"The concern is that the high food prices consumers around the world are seeing will reduce demand. The U.S. soybean export program is already looking poor now," Ammermann said.

The U.S. harvest of corn and soybeans is progressing under clear skies across much of the Midwest this week, adding seasonal pressure to the markets as traders awaited more information on harvested yields.

"We don't have a good handle on fundamentals. We are still trying to figure out what yields are," said Alan Brugler, president of Brugler Marketing.

Commodity brokerage StoneX raised its estimate of the average U.S. corn yield to 173.9 bushels per acre (bpa), from 173.2 previously, but lowered its corn production estimate to 14.056 billion bushels, from 14.168 billion last month.

For soybeans, StoneX lowered its forecast of the U.S. 2022 yield to 51.3 bpa from its Sept. 1 figure of 51.8. The firm forecast U.S. soybean production at 4.442 billion bushels, down from 4.515 billion previously.

The U.S. Department of Agriculture is scheduled to release updated crop estimates on Oct. 12. (Reporting by Michael Hogan in Hamburg, additional reporting by Naveen Thukral in Singapore, editing by Kirsten Donovan)