CBOT soybeans are now leading grain futures higher, with the most-active contract up 4.1% to nearly $12 a bushel. On top of a changing weather forecast, also giving soybeans a boost are continued hopes for China to begin buying U.S. crop exports en masse. "That has shifted momentum in the bulls' favor coming out of the holiday weekend," says Brian Grete of Commstock Investments. No new flash sales were announced by the USDA this morning. (kirk.maltais@wsj.com)