The government said Thursday that worldwide wheat stocks are dwindling, as big wheat seller Russia and its neighbors slash exports. The agriculture department also reported record crops in corn and soybeans, while raising forecasts for U.S. wheat exports.

A sharp reduction in Russian wheat output forecasts and rising crop yields in the United States should spell a jump in U.S. grain exports.

“We now become the world’s storefront in terms of grains and oilseed products,” farm economist Dan Basse of AgResource said in a video report on the Chicago Mercantile Exchange website.

The agriculture department said there should be 175 million tons of wheat on hand at the end of the 2010-2011 growing season, down from last month’s estimate of 187 million tons. The cutback reflects a sharp drop in exports from Russia and its former Soviet satellite states, some of which have stopped exports in response to Russia’s worst drought in 50 years.

Russian President Dmitry Medvedev said Thursday that Russia has lost a quarter of its grain crop during a monthlong heat wave that produced Moscow’s highest-ever recorded temperature. Medvedev said exports may not resume till next year.

Wheat for December delivery at the Chicago Board of Trade rose 16 cents a bushel, to $7.41. That’s well below last week’s peak above $8 a bushel, but commodity watchers said tight supplies could push prices higher in coming weeks.

Those prices are good news for U.S. farmers, who stand to sell some of their large wheat stocks at high prices. The USDA said it expects the average selling price for a bushel of wheat to rise to $5.10 this year. That’s up from its previous forecast of $4.60, but still more than $2 below the current price.

The United States exported $37.2 billion of food and live animals in the first half of 2010, according to government data, along with $1.9 billion of animal and vegetable oils, fats and waxes. The U.S. runs a surplus in the two categories taken together.

“There is no question this is an opportunity for us and we’re going to take advantage of it,” Agriculture Secretary Tom Vilsack said Wednesday on a conference call with reporters.

At the same time, global wheat stocks remain robust, which should mute any talk of food shortages. A wheat shortage in early 2008 following two years of drought in big exporter Australia sent prices soaring to $15 a bushel and set off food riots overseas.

Vilsack expressed confidence Wednesday that another food panic would be avoided, thanks to large wheat stocks, and the USDA made the same point Thursday.

“At 174.8 million tons, world stocks are projected 49.9 million tons higher than in 2007/08 when prices soared to record levels,” the USDA said.

But Russia’s wicked weather offers a reminder of how tightly wound the grain markets are, and the problems that can develop with just one bad season at a major grain exporter. If wheat markets look nervous now, imagine what might break out if we get another big crop failure next year.