(Updates U.S. market activity to close)
CHICAGO, Feb 22 (Reuters) - U.S. grain and soy futures were about flat on Thursday in largely technical-driven trading as investors awaited supply and demand estimates from an annual Department of Agriculture forum due early on Friday.
USDA on Thursday predicted U.S. plantings of corn and soybeans at 90 million acres each and wheat slightly above last year at 46.5 million acres. The estimates were generally in line with analyst expectations.
The government will issue longer-term supply and demand forecasts as well as weekly U.S. export sales results on Friday.
Soybean futures were narrowly lower and corn slightly higher at the Chicago Board of Trade, both still near the multi-month peaks notched on Tuesday, when trading resumed following disappointing weekend rainfall in drought-stricken Argentina.
CBOT March soybeans settled down 2-1/4 cents at $10.32 per bushel. CBOT March corn was up 1 cent at $3.66-3/4, and CBOT March wheat up 4 cents at $4.51-1/4.
Wheat steadied after a two-week low linked to beneficial moisture in the U.S. Plains and a backdrop of ample global supplies.
Argentina remained the focus for soybean markets, with traders assessing production downgrades by forecasters along with prospects for light rain next week and a bumper harvest in Brazil.
Argentine farmers were expected to harvest 47 million tonnes of soy this season and not the 50 million tonnes forecast earlier, the Buenos Aires Grains Exchange said in its weekly crop report.
"Argentina's output can go down further if the weather does not improve," said one India-based agricultural commodities analyst at an international bank. "But the country has 14 million tonnes of inventory, it is enough to restrict further gains in prices. Brazil has another huge crop on the way."
Intermittent showers were expected over the next week in some parts of Argentina, the Commodity Weather Group said in a note.
"Wetter risk (is showing) on some models in 6-10 days, but our outlook would keep up to 60 percent of Argentine corn/soy under moisture stress," it said. (Additional reporting by Naveen Thukral in Singapore and Gus Trompiz in Paris; Editing by Matthew Lewis and Leslie Adler)