* Traders monitor forecasts for Brazil rains

* USDA reports more US soybean export sales

* US backs ethanol sector on aviation fuel tax credits

CHICAGO, Dec 15 (Reuters) - U.S. soybean futures finished higher in the nearby contract and lower in deferred months on Friday as traders waited to see whether beneficial rains will arrive in dry areas of Brazil as expected.

Traders are watching forecasts closely as crop losses due the poor weather in Brazil, the world's top soybean supplier, could boost export demand for U.S. soy on the global market.

Strong demand for U.S. soy cargoes and dryness in Brazil production have underpinned soybean futures recently, but forecasts project beneficial showers in northern Brazil starting late next week.

"We're dependent on South American weather, no doubt," said Don Roose, president of brokerage U.S. Commodities.

Most-active soybean futures ended 1-3/4 cents higher at $13.15-3/4 per bushel at the Chicago Board of Trade. The contract gained 0.9% for the week, its first weekly increase since early November.

CBOT grains also finished higher, with March corn rising 3-3/4 cents to $4.83 a bushel and March wheat jumping 13-1/2 cents to $6.29-1/4 per bushel. For the week, corn eased 0.5% and wheat slipped 0.4%.

The U.S. Department of Agriculture said in a daily reporting system that exporters sold 447,500 metric tons of U.S. soybeans to unknown destinations and another 134,000 metric tons to China. It was the eighth consecutive session in which the USDA announced a daily soybean sale.

Domestic demand also looked solid, as monthly National Oilseed Processors Association data showed the U.S. soybean crush in November topped most trade estimates and rose to the second-highest level for any month.

In other news, the Biden administration said it will recognize a methodology favored by the ethanol industry in guidance to companies looking to claim tax credits for sustainable aviation fuel, a pivotal win for the politically powerful U.S. corn lobby.

The decision has helped underpin CBOT corn, though the market still lacks direction, brokers said. (Reporting by Tom Polansek in Chicago Additional reporting by Naveen Thukral; Editing by Sherry Jacob-Phillips, Subhranshu Sahu, Chizu Nomiyama and Diane Craft)