GRAINS-U.S. wheat, soybean futures firm; corn close to unchanged

(Recasts, updates with U.S. trading, adds new analyst quote, changes byline, dateline; previous SYDNEY)

CHICAGO, July 26 (Reuters) - U.S. wheat futures firmed on Wednesday, with MGEX spring wheat contracts posting the biggest gains as results from a crop tour confirmed that drought in the northern Plains severely crimped harvest potential in that key growing region.

"I think the wheat is a little bit higher here this morning because the spring wheat crop tour is showing results that you would have expected," said Mark Gold, managing partner at Top Third Ag Marketing.

Traders also noted bargain buying in wheat futures as the benchmark Chicago Board of Trade soft red winter wheat contract and K.C. hard red winter wheat had fallen for nine of the previous 10 sessions.

Bargain buying lent support to soybean futures too following a sharp sell-off on Tuesday. Corn was close to unchanged, with the market seen as technically weak after closing near session lows on Tuesday.

Traders were closely monitoring the weather as both corn and soybeans were in key development periods.

"In the coming weeks, the weather forecast in the U.S. will become increasingly more important for the market," ING Bank said in a note, stressing speculators had already switched from a net short to a net long position due to weather risk.

At 10:50 a.m. CDT (1550 GMT), Chicago Board of Trade soft red winter wheat for September delivery was up 2-3/4 cents at $4.76-3/4 a bushel. K.C. September hard red winter wheat was 2-1/4 cents higher at $4.75 a bushel.

MGEX spring wheat was up 6-1/2 cents at $7.24 a bushel.

Spring wheat prospects are lower than last year in southern North Dakota and neighboring sections of South Dakota and Minnesota, scouts on an annual crop tour said on Tuesday.

CBOT December corn futures were up 1/4 cent at $3.82-1/2 a bushel and CBOT November soybeans were 6-1/2 cents higher at $9.99-1/4 a bushel.

Analysts said the real impact of heavy rainfall across the U.S. Midwest growing regions last weekend was still unclear.

"It remains to be seen whether yields will improve noticeably. After all, not all growing regions experienced the rainfall, and some areas are still suffering from an acute shortage of rain," Commerzbank said in a note. (Additonal reporting by Colin Packham in Sydney and Sybille de La Hamaide in Paris; Editing by Elaine Hardcastle and Phil Berlowitz)