ANALYSIS-Storm clouds darken prospects for US corn exports

* Rain-related quality issues threaten future corn sales

* U.S. corn sales lag as prices rise

* U.S. soy sales buoyed by resilient Chinese demand

CHICAGO, Oct 29 - Stormy weather in the U.S. Midwest has hobbled export sales of U.S. corn as the slowest harvest in years helped push prices above $4 a bushel, depriving potential buyers of the discount they usually enjoy at this time of year.

All the wet weather also has hurt the quality of the corn crop, worrying buyers. As a result, the U.S. Department of Agriculture may lower its corn export goal for 2009/10, analysts said.

"The simple fact of the matter is that bad quality does not sell well," said Charlie Sernatinger, an analyst with Fortis Clearing Americas.

USDA on Thursday reported weekly export sales of corn below 400,000 tonnes for the second straight week -- well short of trade expectations.

Corn sales in the week ended Oct. 22 totaled 367,200 tonnes, up 56 percent from the previous week but down 44 percent from the prior four-week average.

The sub-par total for that week coincided with a weather rally that sent Chicago Board of Trade corn futures above $4 a bushel for the first time since June.

Corn futures have since backed down, reflecting better weather forecasts and a rebound in the U.S. dollar. CBOT December corn settled Thursday at $3.79-1/2 a bushel.

Export buyers have been waiting for the seasonal break in prices normally brought by the harvest. But wet weather has meant the slowest-paced corn harvest in at least 24 years, keeping nearby supplies scarce and cash markets firm.

With the weak dollar also inflating commodity prices, U.S. corn was priced out of the world market, at least until prices softened this week.

"We weren't doing any business. We were uncompetitive with South America," said Dan Cekander, an analyst with Newedge USA. "That's why, for those two weeks, we were just out of the market," he said.

Even with the downturn on the CBOT, questions about the quality of the rain-soaked corn crop are giving buyers pause.

"We really don't have a good handle on what kind of quality... can be offered out," said Shawn McCambridge, analyst with Prudential Bache Commodities.

"I think exporters might be holding back, waiting to see from a quality standpoint, what they can reasonably fulfill."

McCambridge said U.S. corn sales will have to jump closer to 1 million tonnes a week to stay on pace for USDA's current export target for the year.

USDA lowered its goal for 2009/10 corn sales this month to 2.15 billion bushels, from 2.20 billion in September.

"If we don't see those type of sales," he said, "then we could start to bring some doubt to that USDA export figure."

Sernatinger estimated that USDA's export figure was 200 million bushels too high.

CHINA CONTINUES TO BOLSTER US SOY SALES

Weekly sales of soybeans came in at 691,000 tonnes, topping trade estimates for 400,000 to 600,000 tonnes, as China remained a big buyer.

"China is the feature. There were some rumors they had rolled some cargoes forward, but the bottom line is, they keep buying U.S. beans," said Cekander.

China's share of the weekly U.S. sales total was 437,000 tonnes, bringing its cumulative total for the 2009/10 marketing year to 13.9 million tonnes -- more than double their year-ago purchases by this point of 6.96 million tonnes.

WHEAT SALES LAG

Export sales of U.S. wheat for the week were 365,700 tonnes (347,700 tonnes for 2009/10), below analysts' forecasts for 400,000 to 600,000 tonnes.

Sales of U.S. wheat continue to lag due to a global oversupply and cheaper supplies elsewhere, including the Black Sea region.