GRAINS-Corn, soy firm after benign USDA data as market looks ahead to U.S.-China trade deal

* USDA raises U.S. corn, soy production outlook

* USDA demand outlook in question ahead of U.S.-China trade deal

* Wheat turns down as U.S. winter crop acres near expectations (Rewrites throughout with updated U.S. Department of Agriculture supply/demand estimates, adds quote, updates prices, changes byline, changes dateline from LONDON)

CHICAGO, Jan 10 (Reuters) - U.S. corn and soybean futures were steady to higher on Friday as investors looked past revised U.S. Department of Agriculture (USDA) supply-and-demand projections and focused on improved prospects for exports to China, which is due to sign an interim trade deal with the United States next week.

The USDA data, released during Friday’s trading session, showed modest changes to crop production and stocks but did not include the agency’s outlook for post-trade deal demand from China.

The USDA’s eagerly awaited estimates for 2019 U.S. corn and soybean production also remained uncertain after the agency said it would resurvey farmers in five northern states where poor weather left many acres unharvested.

“This report is not a game changer,” said Don Roose, president of U.S. Commodities in West Des Moines, Iowa.

“We were handcuffed going into the report with larger supplies around the world with improved weather in South America and hopes of some better demand from China. We come out of the report looking at the same thing,” he said.

Chicago Board of Trade March corn was 2 cents higher at $3.85-1/4 a bushel by 11:55 a.m. CST (1755 GMT), reversing a pre-report drop to $3.76-1/2 a bushel, the lowest since Dec. 13.

March soybeans gained a penny to $9.44-1/2 after dropping shortly after the USDA data release to a three-week low of $9.35-1/2.

CBOT March wheat fell 2-3/4 cents to $5.59-1/2 a bushel. The contract peaked at $5.68-1/2 a bushel ahead of the report, which was the highest for a most-active contract since August 2018. (Reporting by Karl Plume in Chicago; Additional reporting by Nigel Hunt in London and Naveen Thukral in Singapore, Editing by Maju Samuel and Grant McCool)