* Soybeans, wheat lower for third straight session
* Rain expected in drought-hit Argentina late next week
* Strong export demand underpins corn (Rewrites throughout, adds quote, updates prices, changes byline, changes dateline from PARIS/SINGAPORE)
CHICAGO, Feb 2 (Reuters) - U.S. soybean futures fell for a third straight session on Friday on technical selling and as an improved South American crop weather forecast soothed some anxiety about drought-reduced production in Argentina.
Wheat also declined, with soft red winter wheat futures pressured by forecasts for snow in some U.S. production areas.
Corn was little changed as pressure from an improved Argentine weather forecast was offset by rising U.S. export demand.
Grain markets were on pace for their third straight weekly gains, while soybeans appeared poised to end the week lower for the first time in three weeks.
The market's focus is shifting to next week's monthly U.S. Department of Agriculture supply and demand reports, when the agency is expected to adjust its South American crop estimates following a stretch of adverse weather.
Forecasts for rain and less intense heat have eased jitters about Argentine drought damage, while a drier outlook in Brazil could help harvesting of what is expected to be another bumper crop.
Several private forecasters this week cut their forecasts for Argentine crops but expanded Brazilian harvest views.
"If we lose 2 or 3 million metric tons in bean supply in Argentina, it could be offset by an equivalent amount in Brazil," said Mike Zuzolo, president of Global Commodity Analytics.
The soybean market is also facing pressure from tepid demand for U.S. cargoes. Export sales fell to a seven-month low last week as stiff competition from rival exporter Brazil and concerns over lower U.S. crop quality dented demand.
Chicago Board of Trade March soybeans were down 5-1/4 cents at $9.79-3/4 a bushel by 12:12 p.m. CST (1812 GMT). The contract failed to breach chart resistance at its 100-day moving average, and selling accelerated as prices fell below its 50- and 200-day moving averages.
CBOT March corn was flat at $3.61-3/4 a bushel, on pace for a more than one-percent weekly advance.
The USDA reported another 365,000 tonnes of U.S. corn export sales on Friday, its seventh daily corn sales announcement in nine days.
CBOT March soft red winter wheat shed 2 cents to $4.49 a bushel. K.C. March hard red winter wheat was down 1/4 cent at $4.66-3/4 a bushel.
Forecasts for snow in the central and eastern U.S. Midwest weighed on the market as the protective snow cover and increased moisture was seen boosting the SRW crop. Dry conditions in the U.S. Plains offered underlying support to the HRW market.
(Additional reporting by Naveen Thukral in Singapore and Gus Trompiz in Paris; Editing by Joseph Radford, David Goodman and Susan Thomas)