GRAINS-Corn, soy firm on bargain-buying after one-month lows

* Corn supported by bullish INTL FCStone yield forecast

* Soy consolidates above near one-month low

* Gains checked by non-threatening U.S. weather outlook

* Wheat retreats on technical selling; Russian crop eyed

(Recasts; updates prices, adds quotes, changes byline, changes dateline from previous PARIS/SYDNEY) CHICAGO, Aug 2 (Reuters) - U.S. corn and soybean futures firmed on Wednesday, rebounding from one-month lows set in both commodities a day earlier, but outlooks for improved weather for U.S. crops continued to keep prices in check. Chicago Board of Trade wheat futures fell, retreating from early advances on technical selling and easing global supply concerns. As of 12:55 p.m. CDT (1755 GMT), CBOT December corn was up 2-1/2 cents at $3.79 per bushel and November soybeans were up 6-1/4 cents at $9.78 a bushel. Corn drew support from a bullish U.S. corn yield estimate from commodity brokerage INTL FCStone. The firm late Tuesday projected the U.S. corn crop at 13.590 billion bushels, with an average yield of 162.8 bushels per acre (bpa). That was well below the USDA's most recent forecast for a corn crop of 14.255 billion bushels, with a trend-based yield of 170.4 bpa. "The market is getting a little support out of the FCStone numbers, especially the corn. But the market is unenthused about trying to take off and rally," said Brian Hoops of Midwest Market Solutions. Weather forecasts, he added, showed few serious threats in the next two weeks for the heart of the U.S. Midwest crop belt, where the corn crop is filling kernels and soybeans are in the key pod-setting phase. "Soybean crops now seem less at peril from hot summer weather," said Tobin Gorey, director of agricultural strategy, Commonwealth Bank of Australia. Wheat futures were headed for a third straight lower close. CBOT September wheat was down 2-1/2 cents at $4.58-3/4 a bushel after dipping to $4.55-3/4, the contract's lowest since mid-June. Extremely poor conditions for U.S. spring wheat were seen as largely priced in, with harvesting of the drought-hit crop now under way, while rising expectations for production in rival exporter Russia were tempering supply concerns. Russian agriculture consultancy IKAR on Tuesday increased its estimate for this year's wheat production in Russia to a record 74-77 million tonne range. "If Russia were indeed to harvest a crop at the upper edge of IKAR's estimate, this would offset the weather-related crop shortfalls in the U.S.," Commerzbank analysts said in a note.

CBOT prices as of 12:54 p.m. CDT (1754 GMT):

Net Pct Volume

Last change change

CBOT wheat WU7 458.50 -2.75 -0.6 71814 CBOT corn CZ7 378.50 2.00 0.5 105340 CBOT soybeans SX7 977.50 5.75 0.6 96432 CBOT soymeal SMZ7 315.60 1.10 0.4 34744 CBOT soyoil BOZ7 34.51 0.23 0.7 40564

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 Colin Packham in Sydney and Gus Trompiz in Paris; Editing by Pritha Sarkar and Grant McCool)