* Hot, dry spell in Midwest supports soybean prices
* Soy, corn markets assess crop tour findings
* Wheat market monitors N. America drought, Black Sea war damage
CHICAGO, Aug 24 (Reuters) - Chicago soybean futures firmed for a second straight session on Thursday, supported by strong exports and supply uncertainty as hot, dry weather cast uncertainty over U.S. prospects.
Corn inched down as the market assessed results from this week's Pro Farmer crop tour.
Wheat eased as traders weighed strong global supplies against weak demand for U.S. wheat.
The most-active soybean contract on the Chicago Board of Trade (CBOT) gained 4 cents to $13.64-1/2 a bushel by 11:15 CDT a.m. (1615 GMT).
CBOT corn eased 4-1/2 cents to $4.86 a bushel while wheat trimmed 7-1/2 cents to $6.32-1/4 a bushel.
Soybeans are especially susceptible to extreme temperatures this week and a lack of rainfall for the next several weeks, even as temperatures moderate.
"With this hot forecast in pod-filling season, how much damage is that going to do to the bean plant?" said Dan Smith, senior risk manager at Top Third Ag Marketing. "I'm not sure they'll fill out."
Analysts were also watching a firm currency trend in Brazil, which could help make U.S. soybean exports more competitive.
This week's Midwest crop tour has generally shown soy and corn potential above last year's but mixed levels compared with the average of recent years.
Illinois soybean pod counts and corn yield prospects are above last year and the three-year average, scouts on an annual Midwest crop tour found on Wednesday, limiting gains.
Corn yield prospects are near to below average across western Iowa, tour scouts also found.
For the week, soybean export sales of 1.583 million metric tons were above analysts' forecasts, ranging from 550,000 to 1.45 million metric tons.
Corn and wheat export sales were within analyst expectations.
"Both corn and wheat haven't been able to find much export business," said Chuck Shelby, president at Risk Management Commodities. "What we're waiting for is to see if we're below a bargain price and world buyers decide to come back."
Wheat drifted lower as markets assessed global supplies against U.S. prices.
Market reaction was limited after a Russian drone strike at a Ukrainian grain facility at the Danube River port of Izmail on Wednesday.
Overall Black Sea supply remains strong as massive Russian wheat exports continue.
Consultancy Agritel on Thursday forecast Russian wheat exports at 49 million metric tons in 2023/24, joining other analysts in anticipating a new record for Russia this season. (Reporting by Christopher Walljasper in Chicago Additional reporting by Gus Trompiz in Paris and Naveen Thukral in Singapore Editing by Matthew Lewis)
