CHICAGO, Nov 1 (Reuters) - Benchmark U.S. corn futures fell to their lowest in seven weeks on Wednesday as the harvest continued and showed better than expected yields, while weather forecasts improved in crop areas of South America.

Wheat and soybean prices were modestly higher in range-bound trading.

By 12:59 p.m. CDT (1759 GMT), Chicago Board of Trade (CBOT) corn was down 3 cents at $4.75-3/4 per bushel. January soybeans were up 4-1/2 cents at $13.15 a bushel and December wheat was up 6-3/4 cents at $5.63 a bushel.

As the U.S. corn and soybean harvest wound down, traders have been shifting their focus to South American crops.

"The weather does improve for central and northern Brazil, and more importantly, Argentina, especially (with) the rains to pick up after this weekend," Marex Capital analyst Terry Reilly said, adding that export demand for U.S. corn supplies has been poor.

"There is not too much of a bullish theme in the corn market," Reilly said.

Meanwhile, wheat futures edged higher, although the most-active CBOT December contract stayed inside of Tuesday's trading range.

Brokers continued to monitor tensions in the Black Sea region. Ukraine said Russian warplanes had dropped "explosive objects" into the likely paths of civilian vessels in the Black Sea three times in the last 24 hours, but that its fledgling shipping corridor was still operating.

"I think renewed Black Sea shipping concerns, along with a possible increase of violence of other countries, in the Middle East, is getting that market a little bit of attention," Reilly said.

China's buying of Australian and French wheat, following rain damage to its crop, has also provided some support for prices with talk of potential demand for both U.S. and Canadian supplies. Strong exports from Russia at very competitive prices continue, however, ensuring that supplies remain ample.

Ahead of the U.S. Department of Agriculture's monthly soy crushing report due later on Wednesday, analysts polled by Reuters on average expect the government to report the September soybean crush at 5.249 million short tons, or 175.0 million bushels, the largest September crush on record.

Brokerage StoneX raised its forecast of Brazil's 2023/24 soybean crop to 165 million metric tons, from 164.1 million previously. (Reporting by Peter Hobson in Canberra and Nigel Hunt in London; Editing by Varun H K and Kirsten Donovan)