GRAINS-Soybeans rise as wet Midwest weather seen halting harvest

* Rains seen disrupting U.S. Midwest corn, soybean harvests

* Wheat boosted by Australia drought, Russia export concerns (Rewrites throughout with U.S. market open, adds quote, updates prices, changes byline, changes dateline from LONDON)

CHICAGO, Oct 5 (Reuters) - U.S. soybean futures rose for the first time in three sessions on Friday as a rainy Midwest forecast fueled worries about harvest delays and potential damage to some crops.

Corn futures eased in a profit-taking setback after strong export demand and worries about U.S. harvest delays lifted prices to one-month highs.

Wheat edged higher as rising global prices fueled optimism of a pickup in demand for U.S. wheat.

Forecasts for several days of rain in the western Midwest has raised concerns that the corn and soybean harvest, which has been ahead of the normal pace, could fall behind. Soybeans, in particular, are vulnerable as they tend to be more susceptible to damage when ripe crops are hit with prolonged rains.

"The weather is definitely keeping beans afloat," said Terry Reilly, senior commodities analyst with Futures International.

"Harvesting efforts are expected to considerably slow across the western Corn Belt over the next 10 days," he said.

Soybeans drew additional support from strong soymeal exports, Reilly said. Government export data, released on Friday, suggest that the U.S. Department of Agriculture is understating its soymeal export forecast by 600,000 to 650,000 short tons, he said.

Additionally, the USDA on Friday reported private sales of 134,000 metric tons of soymeal to the Philippines.

Chicago Board of Trade November soybeans were up 3 cents at $8.62-1/4 a bushel at 11:21 a.m. CDT (1621 GMT), on pace for a 2-percent weekly gain.

December corn was down 1-1/2 cents at $3.66 a bushel after earlier touching a one-month peak of $3.69-1/2. Selling accelerated as the contract fell below its 50-day moving average, but the contract remained on pace for a weekly gain of around 3 percent.

CBOT December wheat futures rose 2-1/2 cents to $5.20-1/2 a bushel, poised for a 2-percent weekly gain.

Wheat prices remain supported by concerns about potential disruptions to shipments from Russia and drought in Australia.

"Despite denials from the authority in question, the market clearly still expects that wheat shipments from Russia may soon be restricted. What is more, crop estimates for Australia are being revised further downwards," Commerzbank said in a market note.

Wheat prices have been lifted this week by reports that Russian authorities may suspend operations in 30 grain loading points in two of the country's top exporting regions.

The country's safety watchdog subsequently said it had no immediate plans to do so.

(Additional reporting by Colin Packham in Sydney and Nigel Hunt in London; Editing by Dale Hudson and Susan Thomas)