* Crop tour forecasts U.S. corn, soy crops below USDA estimates

* Forecasts of more hot, dry weather threaten U.S. soybean yields

* Second vessel leaves Odesa through temporary Black Sea corridor

HAMBURG, Aug 28 (Reuters) -

Chicago soybeans and corn rose on Monday after a U.S. farm survey found that hot and dry weather stressed both crops, which could result in smaller harvests than the U.S. government forecasts.

Wheat fell on competition from cheap Russian supplies.

Chicago Board of Trade most-active soybeans rose 0.9% to $13.99-1/4 a bushel at 1116 GMT. Corn rose 0.8% to $4.92 a bushel, wheat fell 0.7% to $6.17-1/4 a bushel.

Soybeans earlier on Monday hit $14.09-1/2 a bushel, the highest since July 27.

“Soybeans and corn are underpinned today by the Pro Farmer report on Friday which forecast U.S. harvests below the USDA,” said Matt Ammermann, StoneX commodity risk manager. “There remains a risk to U.S. crops from the forecasts of dryer, hotter weather in the U.S. Midwest.”

U.S. 2023

soybean production

could total 4.110 billion bushels, advisory service Pro Farmer said after Friday’s market close, below the 4.205 billion bushels forecast by the U.S. Department of Agriculture (USDA).

Pro Farmer predicted the U.S. corn crop to be 14.960 billion bushels, below the USDA's most recent estimate of 15.111 billion bushels.

“After Pro Farmer, there will be debate about downward risks to U.S. soybean yields," he said. "Pro Farmer forecast U.S. soybean yields of 49.7 bushels per acre, the debate could now be if we truly have risk of the soybean yield decreasing below 50 bushels per acre.”

Unwelcome Hot and dry weather in the U.S. Midwest is forecast this week.

“Wheat is falling as large volumes of cheap Russian wheat continue to

flow into

world markets," Ammermann said. "U.S. and other wheat is looking in theory more competitive in terms of futures prices against Russian wheat, Russian cash prices for physical delivery are in reality considerably lower.”

“Russian sea exports have not been disrupted recently by the war.” (Reporting by Michael Hogan, additional reporting by Peter Hobson and Naveen Thukral; Editing by Sherry Jacob-Phillips, Subhranshu Sahu and Louise Heavens)