* Grain markets consolidate before Sept. 12 USDA forecasts
* Big Russian crop weighs on wheat
* Focus of USDA report to be corn, soybean yield revisions
(New throughout; updates prices, adds quotes, changes dateline; previous PARIS/SINGAPORE) CHICAGO, Sept 11 (Reuters) - U.S. wheat futures dipped to a one-week low on Monday as swelling harvest supplies in the Black Sea export region hung over a subdued market a day ahead of closely watched U.S. government crop forecasts. Soybean futures also declined, while corn was fractionally higher in choppy trade. As of 12:46 p.m. CDT (1746 GMT), Chicago Board of Trade December wheat was down 3-1/4 cents at $4.34-1/2 per bushel after dipping to $4.31-1/2, its lowest since Aug. 31. CBOT November soybeans were down 3-1/2 cents at $9.58-1/2 a bushel while December corn was unchanged at $3.56-3/4 a bushel. Wheat slipped as traders braced for the U.S. Department of Agriculture's monthly supply/demand reports on Tuesday. Despite a drop in U.S. wheat production this year, a record Russian harvest and a large crop in Ukraine are expected to keep international markets well supplied. "Wheat has been under modest pressure today on ideas that USDA will likely increase Black Sea production in tomorrows report, although its capacity to export what it produces is limited, so the global market shouldn't be immediately impacted," Arlan Suderman, INTL FCStone chief commodities economist, wrote in a note to clients. "Furthermore," Suderman said, "we could see USDA lower Australian production by 1 to 2 million tonnes due to dryness." Ahead of the USDA's reports, analysts surveyed by Reuters on average expected the government to trim its forecast of 2017/18 global wheat ending stocks. They also expected the USDA to lower its U.S. 2017 yield estimates for corn and soybeans. CBOT soybeans declined on positioning ahead of the monthly reports, despite support from fresh U.S. soy export sales and forecasts for mostly dry weather this week as the Midwest crop matures. The USDA through its daily reporting system said private exporters sold 352,000 tonnes of U.S. soybeans to unknown destinations. The government reported export inspections of U.S. soybeans in the latest week at 1,106,268 tonnes, topping a range of trade expectations. CBOT corn was choppy, firming at times on short-covering ahead of the report. But pressure from the start of the U.S. harvest limited rallies. Ahead of the USDA's weekly crop progress report due later on Monday, analysts expected the government to show the 2017 U.S. corn harvest as 4 percent complete.
CBOT prices as of 12:46 p.m. CDT (1746 GMT):
Net Pct Volume
Last change change
CBOT wheat WZ7 434.25 -3.50 -0.8 34908 CBOT corn CZ7 356.75 0.00 0.0 88538 CBOT soybeans SX7 958.50 -3.50 -0.4 71076 CBOT soymeal SMZ7 303.40 -1.80 -0.6 36683 CBOT soyoil BOZ7 35.00 0.06 0.2 43140
NOTE: CBOT September wheat, December corn and November soybeans shown in cents per bushel, December soymeal in dollars per short ton and December soyoil in cents per lb.
(Additional reporting by Naveen Thukral in Singapore and Gus Trompiz in Paris; Editing by Louise Heavens and Dan Grebler)