* Soybeans hit two-week high; U.S., Brazilian weather eyed
* Soymeal leads gains, rising 2 pct on strong export demand
* Export sales lift corn to 3-month high on continuous chart
* Wheat firm for third straight session (Updates with closing prices; adds analyst comment on wheat)
By Julie Ingwersen
CHICAGO, Feb 3 (Reuters) - Chicago Board of Trade soybean futures hit a two-week high on Monday, rising on worries about tightening U.S. supplies amid strong demand for soymeal, coupled with expanding dryness in Brazil.
Front-month corn futures set a three-month high as export demand and chart-based strength triggered a round of short-covering. Wheat rose as traders covered short positions.
Additional support for all three markets stemmed from forecasts for frigid temperatures and more snow in the U.S. Midwest this week, which should slow grain movement.
At the CBOT, March soybeans settled up 10 cents at $12.92-3/4 per bushel but failed to break through resistance at $13.00, near the contract's 50-day moving average.
March corn ended up 1-3/4 cents at $4.35-3/4 a bushel after reaching $4.38-3/4, the highest spot price on a continuous chart since late October.
CBOT March wheat settled up 8 cents at $5.63-3/4 a bushel.
"We are going to be seeing another snowstorm, another round of frigid cold. This is beginning to snarl logistics. So far it's been only a marginal problem, but after a while it begins to pile up," said Sterling Smith, futures specialist at Citigroup in Chicago.
Soybean meal <0#SM:> posted the biggest gains on the CBOT grains floor, with the March contract rising nearly 2 percent and settling up $7.90 at $434 per short ton.
Export demand for U.S. soymeal has been strong due to reduced output from Argentina, the world's top supplier of the feed ingredient, where producers are holding on to dollar-denominated soybeans as a hedge against rampant inflation.
"The crush margins in the United States are just huge," said Roy Huckabay at the Linn Group, a Chicago brokerage.
CBOT soybeans also drew support from worries about expanding dryness in Brazil, projected as the world's biggest soy supplier. The harvest of a likely record-large Brazilian soybean crop is under way but crops are still developing in some areas.
Most of Brazil's soy belt will see net drying this week, said Drew Lerner, an agricultural meteorologist at World Weather Inc.
"The drying in Brazil will lead to some stress for some of the late-season soybeans," Lerner said, adding parched conditions could limit the planting of second-season corn that Brazilian farmers typically plant behind soybeans.
Front-month corn rose to its highest level since late October on improving export demand. The U.S. Agriculture Department last week reported weekly corn export sales at 1.8 million tonnes, the most so far in the 2013/14 marketing season.
On Monday, USDA reported a sale of 113,780 tonnes of U.S. corn to unknown destinations for 2013/14 delivery.
"Our export sales last week were excellent. I think our demand is going to be really strong," said Joe Vaclavik, president of Standard Grain in Chicago.
Buying accelerated as the March contract broke above its mid-January high of $4.35-1/2 a bushel, established the following session after USDA revised its U.S. 2013 production estimate below trade expectations.
Monday's rally appeared to trigger moderate farmer sales of U.S. corn, pushing futures off their session highs, traders said.
CBOT March wheat advanced for a third straight session after hitting a 3-1/2 year low last week.
"Wheat has been oversold for weeks. We are seeing profit-taking, some short-covering," said Shawn McCambridge, analyst at Jefferies Bache in Chicago. Firm cash markets for U.S. soft red winter wheat added support.
However, he added, world wheat supplies remain plentiful, a factor that limited the rally.
Prices at 2:16 p.m. CST (2016 GMT)
CHG CHG CHG CBOT corn 435.75 1.75 0.4% 3.3% CBOT soy 1292.75 10.00 0.8% -1.5% CBOT meal 434.00 7.90 1.9% -0.8% CBOT soyoil 37.45 -0.19 -0.5% -3.5% CBOT wheat 563.75 8.00 1.4% -6.9% CBOT rice 1530.00 -10.00 -0.7% -1.4% EU wheat 192.25 -0.25 -0.1% -8.0%
US crude 96.60 -0.89 -0.9% -1.8% Dow Jones 15,406 -293 -1.9% -7.1% Gold 1256.06 12.87 1.0% 4.2% Euro/dollar 1.3526 0.0039 0.3% -0.9% Dollar Index 81.0390 -0.2720 -0.3% 1.3% Baltic Freight 1093 -17 -1.5% -52.0%
Additional reporting by Gus Trompiz in Paris; Editing by Bernadette Baum; and Peter Galloway