* Flooding in southern Brazil threatens soy, corn crop losses

* Wheat rallies on volatile weather in Russia

* Traders await US crop updates

(Updates prices at 11:56 a.m. CDT (1656 GMT); adds analyst quotes, Russian weather; changes byline, dateline from PARIS/SINGAPORE)

CHICAGO, May 6 (Reuters) - Chicago soybean, wheat and corn futures all jumped to multi-month highs on Monday on worries about potentially crop-damaging weather in Brazil and Russia and as traders awaited updates on U.S. plantings and crop conditions.

Chicago Board of Trade (CBOT) July wheat futures were up 22-3/4 at $6.45-1/4 a bushel by 11:56 a.m. CDT (1656 GMT), after climbing to its highest level since December.

CBOT July corn was up 7-1/4 cents at $4.67-1/2 a bushel, having reached its highest point since January, while July soybeans climbed 27 cents to $12.42 a bushel, also reaching four-month peaks.

Wheat's rise was driven by volatile weather conditions in Russia, including dryness in the south of the country and May frosts in some areas.

Consultancy IKAR

cut

its forecast for the world's largest wheat exporter last week.

Meanwhile, the outlook for the soybean harvest in Brazil's Rio Grande do Sul state is deteriorating, after torrential rains flooded fields, with about a quarter of beans left to harvest.

The deluge may also reduce the state's corn volumes and further clip South American supply after downgrades to estimates of Argentina's crop.

Grain traders were also monitoring U.S. Midwest corn and soybean planting progress amid adverse weather at times, said Bill Lapp, president of Advanced Economic Solutions.

Volatile weather stories were also prompting fund activity, analysts said.

"We're starting to see the funds over the last few weeks start to flip out of their commodity deflation mode that they've been in for the last two years, said Arlan Suderman, chief commodities economist at StoneX.

"There were fundamental stories that were being ignored before that suddenly that markets are paying attention to," he said.

The market will get updates on wheat conditions and corn and soybean planting progress from the U.S. Department of Agriculture later on Monday. The USDA will then issue monthly world supply and demand projections on Friday.

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