GRAINS-U.S. corn drops to lowest since March; wheat off for 7th day

* Soybeans drop to session lows after NOPA data

* Wheat down 7.4 percent during losing streak

* Forecasts for better weather add pressure

(Updates with U.S. trading, adds new analyst comment, changes byline, dateline) CHICAGO, May 15 (Reuters) - U.S. corn futures fell 2.1 percent on Thursday to a seven-week low on a technical setback and forecasts for improved planting weather in northern areas of the U.S. Corn Belt by the weekend, traders said. Wheat and soybean futures also were lower, with wheat dropping for the seventh day in a row due to ample global supplies that were chilling demand for U.S. offerings on the export market. Chicago Board of Trade corn futures have fallen for four out of the last five days as the pace of planting has picked up in the U.S. Midwest following weeks of delays in key growing areas such as Iowa. "The corn is moving lower again today as the market is working its way through the nearby support areas," Sterling Smith, futures specialist with Citigroup, said in a note to clients. "Planting conditions and the weather is expected to improve by the weekend, and there should be improvement in the northern plains situation by next weekend." The benchmark CBOT July corn contract was down 10-1/2 cents at $4.85 at 11:40 a.m. CDT (1640 GMT). The contract fell through the low end of the 20-day Bollinger range for the first time since Jan. 10. The front-month CBOT wheat contract hit a three-week low. The seven-session losing streak has wiped out 7.4 percent of the contract's value. CBOT July wheat was 12-1/4 cents lower at $6.78 a bushel. "Traders are also looking at a wetter forecast this morning for stressed hard red winter wheat fields," said Bryce Knorr, senior editor at Farm Futures Magazine. Scattered showers were possible in the central U.S. Plains from Friday into the weekend with a better chance for rain forecast for the end of next week, according to Commodity Weather Group's outlook. The U.S. Agriculture Department's export sales report released on Thursday morning showed that old-crop export sales of wheat were just 54,900 tonnes, below a range of trade forecasts for 100,000 to 300,000 tonnes. Old-crop corn export sales of 343,000 tonnes were in line with expectations while old-crop soybean export sales of 73,600 tonnes topped the range of analysts' forecasts. Soybean futures were down 1.5 percent, falling to session lows after the National Oilseed Processors Association's monthly crush data showed that the pace of crushing was roughly in line with expectations during April. CBOT soybeans for July delivery were 20-1/2 cents lower at $14.66-1/4 a bushel. NOPA said that processors crushed 132.667 million bushels of soybeans during April, the heaviest for the month in five years.

Prices at 11:42 a.m. CDT (1642 GMT)

LAST NET PCT YTD CHG CHG CHG CBOT corn 481.75 -9.00 -1.8% 14.2% CBOT soy 1399.75 -16.25 -1.2% 6.6% CBOT meal 452.80 -6.60 -1.4% 3.4% CBOT soyoil 41.08 -0.21 -0.5% 5.8% CBOT wheat 687.00 -12.00 -1.7% 13.5% CBOT rice 1451.00 3.00 0.2% -6.4% EU wheat 199.00 -2.00 -1.0% -4.8% US crude 101.45 -0.92 -0.9% 3.1% Dow Jones 16,430 -184 -1.1% -0.9% Gold 1296.10 -8.90 -0.7% 7.5% Euro/dollar 1.3707 -0.0007 -0.1% 0.4% Dollar Index 80.0410 -0.0320 0.0% 0.0% Baltic Freight 1021 19 1.9% -55.2%

In U.S. cents, benchmark contracts, except EU wheat (euros) and soymeal (dollars). CBOT wheat, corn and soybeans per bushel, rice per hundredweight, soymeal per ton and soyoil per lb.

(Additional reporting by Naveen Thukral in Singapore and Gus Trompiz in Paris; Editing by Marguerita Choy)