* USDA acreage and stocks reports due on Friday

* Wheat rises with healthy demand

* Canada planting data below expectations

CHICAGO, June 27 (Reuters) - Chicago wheat futures surged on Thursday, recovering from a string of retreats on bargain buying and strong export demand, analysts said.

Corn and soy fell on weaker demand and good crop prospects, and traders of all three commodities positioned themselves ahead of Friday's U.S. Department of Agriculture acreage report.

The most-active wheat contract on the Chicago Board of Trade (CBOT) ended up 19 cents at $5.79-1/2 a bushel. Soybeans settled down 2-1/4 cents at $11.04-3/4 a bushel, the lowest since November 2020. Corn fell 3 cents to $4.22-1/2 a bushel.

September wheat had been oversold, said Mark Soderberg, senior agricultural market analyst at ADM Investor Services, and rose as traders found bargains.

Healthy wheat exports, with Egypt and Algeria among the top importers, were reported on Thursday, indicating strong demand, he said.

The USDA reported net U.S. wheat export sales in the week ended June 20 of 667,200 metric tons for 2024/25, above trade estimates of 200,000 to 600,000 tons.

"The lower prices are doing what they need to, and that's encouraging buying demand here for us," Soderberg said.

In addition, Statistics Canada, the national statistics agency, estimated Canadian all-wheat plantings at 26.641 million acres, below the average trade expectation of 26.943 million. Canada is the world's No. 4 wheat producer.

Traders were positioning ahead of the release of U.S. Department of Agriculture data. The agency is scheduled to release its next quarterly stocks report for June, and its 2024 acreage report on Friday at 11:00 A.M. CDT (1600 GMT).

The market continues to weigh the impact of flooding and extreme heat in top corn and soybean growing areas of the central United States, but Soderberg said the weather remained "non-threatening."

Crop prospects for corn in particular remain good, while demand remains low, he added. (Reporting by Renee Hickman; Additional reporting by Naveen Thukral and Sybille de La Hamaide in Paris; Editing by Alexander Smith and Richard Chang)