CANBERRA, June 18 (Reuters) - U.S. soybean futures were on course to post their biggest weekly loss in nearly seven years, weighed down by forecasts for crop-friendly weather and cooler temperatures in the Midwest crop belt, despite a 3% jump earlier in the day. Wheat rose 1% on Friday, but an advancing U.S. harvest was set to drive the grain towards a weekly loss of 5%, while corn was up 1%. The most active soybean futures on the Chicago Board of Trade were up 3.2% at $13.67-1/2 a bushel, as of 0201 GMT, after closing 8.2% weaker in the previous session when prices hit a Jan 23 low of $13.23-1/2 a bushel. Traders expect showers to bring relief to dry areas of the U.S. Corn Belt over the next two weeks, improving production prospects. Driven by heavy losses, soybeans are down 9% for the week, set for the biggest weekly slide since September 2014. “Many of those grain and oilseed markets had heavy long positions driven by macro views and the momentum tailwinds they create. Selling by that group was a major reason for the falls,” said Tobin Gorey, director of agricultural strategy, Commonwealth Bank of Australia. “We do not think though that much has changed in the tight supply fundamentals.” The most active corn futures were up 1.3% at $6.41-3/4 a bushel, having closed 6% lower in the previous session. Corn is down 6% for the week, having closed 0.2% higher in the previous week. The most active wheat futures were up 1.5% at $6.48-1/2 a bushel, having closed down 3.6% on Thursday. Wheat is down nearly 5% for the week, poised for the second straight weekly slide. (Reporting by Colin Packham, Editing by Sherry Jacob-Phillips) Our Standards: The Thomson Reuters Trust Principles.