CHICAGO (Dow Jones)--Corn futures at the Chicago Board of Trade closed higher and near the session high Wednesday, as updated midday weather forecasts once again added some frost potential in the U.S. Corn Belt next week.

December corn futures closed up 4 1/2 cents at $3.30 1/4 a bushel. March corn closed up 4 1/4 cents at $3.43 1/4.

"There is some potential for frost damage" to the corn crop with the latest noontime weather updates, said Don Roose with U.S. Commodities in Des Moines. Corn futures were under pressure in early trading Wednesday, as overnight weather models backed off from the frost potential in the Corn Belt. On Tuesday, corn futures rallied as weather forecasters predicted the potential for a significant frost event in the Corn Belt next week.

Roose also said early reports of disease as the corn harvest gets under way in the southern U.S. added some support to buying interest in corn futures Wednesday. However, he said such reports tend to typically occur about every year at this time.

Short covering, or the buying back of previously sold positions, was a feature in the corn futures market Wednesday, said a Midwest-based market analyst. "Today's price action, along with trade earlier this week, would suggest a short-term low is in the works. While corn yield estimates remain high, it could be a case where most of the bearish news is already in the market. Plus, funds likely see corn futures as somewhat of a value buy compared to soybeans," he said.

"Other than the weather talk, there's not much going on in the corn market," added Victor Lespinasse, grain analyst with He did say grain traders are keeping an eye on this week's Federal Open Market Committee meeting of the Federal Reserve, and on the G-20 meeting in Pittsburgh. The Fed on Wednesday afternoon did, as expected, make no changes to monetary policy following the two-day FOMC meeting.

The key "outside markets" were mostly neutral for corn futures Wednesday. Crude oil futures prices were solidly lower, the U.S. dollar index was lower and the U.S. stock indexes were higher.

Technically, the corn bulls' next upside price objective is to push prices above solid technical resistance at last week's high of $3.47 3/4 a bushel. The next downside price objective for the bears is to close below major psychological support at $3.00 a bushel. First resistance for December corn is seen at Wednesday's high of $3.37 and then at $3.40. First support is seen at $3.25 and then at Wednesday's low of $3.19.

-By Jim Wyckoff, for Dow Jones Newswires