CANBERRA, Dec 6 (Reuters) - Chicago wheat futures edged lower on Wednesday after confirmation of a second large Chinese purchase of U.S. wheat in two days drove prices to their highest since August in the previous session.

The most-active wheat contract on the Chicago Board of Trade (CBOT) was down 0.2% at $6.30 a bushel by 0617 GMT after reaching $6.36-1/4 on Tuesday, its highest since Aug. 25. Prices have risen about 12% since market open on Nov. 28.

News of the Chinese purchases had triggered some covering of short positions, helping push up prices, said Rod Baker at Australian Crop Forecasters.

"If we see more exports from the U.S., that will definitely be supportive of prices," he said, adding that China may wait to see if prices drift lower again before reentering the market.

China is importing large quantities of wheat after a disappointing harvest.

The U.S. Department of Agriculture (USDA) on Tuesday confirmed private sales of 198,000 metric tons of U.S. soft red winter wheat to China, following a sale of 440,000 tons on Monday, the largest one-off U.S. wheat export sale since at least 2020.

The sales buoyed a wheat market in which speculators and funds hold a huge net short position, making it prone to episodes of short-covering.

Funds were net buyers of CBOT wheat and corn on Tuesday and net sellers of soybeans, traders said.

This week's U.S. sales to China bring the total since the start of October to 1.15 million tons, said StoneX analyst Arlan Suderman.

"China certainly wouldn't pay a premium to source wheat from the United States, so that's a good sign that domestic futures have finally aligned themselves with world values," Suderman said.

Outside the United States, the lowest free-on-board offer presented at an Egyptian state purchasing tender for wheat on Tuesday was $250 a ton, traders said.

Meanwhile, soft wheat exports from the European Union since the start of the 2023/24 season in July had reached 12.52 million tons by Dec. 3, down 18% year-on-year, according to EU data.

Ahead of Friday's monthly USDA supply-and-demand report, analysts surveyed by Reuters expected no change to its forecast of 2023/24 U.S. ending stocks and a slight increase to its forecast of world ending stocks.

CBOT soybeans rose 0.3% to $13.09-1/4 a bushel and corn climbed 0.1% to $4.90-3/4 a bushel.

Soybean prices have fallen around 7% since mid-November as rain and forecasts for further wet weather in drought-afflicted cropping areas in Brazil bolstered prospects for yields in the world's biggest soy supplier. (Reporting by Peter Hobson; Editing by Rashmi Aich and Varun H K)