CANBERRA, Nov 16 (Reuters) - Chicago soybean futures retreated on Thursday from a 2-1/2 month high reached in the previous session as an improving weather outlook in major South American exporters like Brazil eased supply concerns.

Corn prices inched higher despite the forecast rains in Brazil and Argentina. Wheat futures fell amid plentiful near-term supply.

"The trade will be looking at the weather over the coming days to see whether the promised rains arrive," said Andrew Whitelaw at Australian agricultural consultancy Episode 3.

Traders will also be watching discussions between Joe Biden and Xi Jinping in San Francisco, with large Chinese purchases of U.S. soybeans in recent days having helped to lift prices, he said.

The most-active soybean contract on the Chicago Board of Trade (CBOT) was down 0.1% at $13.83 a bushel by 0454 GMT, after touching $13.98-1/2, the highest since Aug. 30, on Wednesday.

CBOT corn rose 0.2% to $4.71-3/4 a bushel and wheat fell 0.3% to $5.58-3/4 a bushel.

Soybeans have rallied 11% from a mid-October low as hot, dry weather in key cropping areas of Brazil, the world's biggest soybean exporter, disrupted planting, but rain is forecast in those regions next week and global supply remains plentiful.

Analysts at Rabobank said they expect "a bumper 163 million metric ton crop haul" in Brazil in 2024 and that Argentina, the biggest exporter of soy products, should recover after last year's harvest failure, boosting global stockpiles.

Argentina's agricultural core saw a much higher-than-average rainfall during the first half of November and will likely see even more moisture in the coming days, the Rosario grains exchange (BCR) said.

Soybeans have also been supported by strong demand in the United States.

U.S. soybean processors crushed a record amount of soybeans in October and end-of-month soyoil stocks fell to the lowest in almost nine years, National Oilseed Processors Association (NOPA) data showed.

Moving to wheat, FranceAgriMer raised its forecast for French soft wheat exports outside the EU in 2023/24 to 10.1 million metric tons and also lifted its season-end stocks estimate to a six-year high, pressuring local prices.

Ukraine's state railway company said it had restricted grain deliveries to Odesa, a key Black Sea port, due to repairs. It did not say when the restrictions would be lifted.

The market has been awash with cheap Russian wheat in recent months, but Rabobank said it expects a fifth consecutive global deficit next year, with Argentina's crop underperforming and Australia delivering much less wheat than in recent years.

Commodity funds were net sellers of CBOT soybeans, soymeal, wheat and corn futures on Wednesday and net buyers of soyoil, traders said.

The U.S. Department of Agriculture (USDA) is expected to issue a weekly report on U.S. export sales at 0730 a.m. CST (1330 GMT) on Thursday. (Reporting by Peter Hobson; Editing by Sherry Jacob-Phillips and Nivedita Bhattacharjee)