Chicago Board of Trade soyabean futures closed higher on Wednesday, supported by optimism about increased Chinese purchases as well as fears that a winter storm in the Upper Midwest could threaten late-maturing crops.

CBOT November soyabeans ended up 3-1/4 cents at $9.23-3/4 per bushel after reaching $9.31-1/2, the contract's highest since July 15.

CBOT December soyameal ended up $2.80 at $309.70 per short ton while December soyaoil fell 0.11 cent to 29.71 cents per pound. Soyabeans advanced after the Financial Times reported that the team of China's lead trade negotiator had offered to boost annual purchases of soyabeans to 30 million tonnes compared with 20 million at present as the two countries seek to resolve their trade dispute.

Vice Premier Liu He, China's top trade negotiator, is scheduled to travel to Washington for their next round of trade talks on October 10-11. Futures also drew support from a winter storm brewing in the northern US Plains that should bring snow and freezing temperatures this week into the Dakotas, Nebraska and portions of Minnesota and Iowa, slowing the harvest and potentially threatening crop yields.

Ahead of Thursday's monthly supply/demand reports from US Department of Agriculture, analysts surveyed by Reuters on average expected the government to lower its estimates of US 2019/20 soyabean yield, production and ending stocks.

Ahead of the USDA's weekly export sales report, also due on Thursday, traders expected the government to show US soyabean export sales in the week to Oct. 3 at 1.3 million to 1.8 million tonnes.