The grains kept ahold of slight gains in the overnight trade Thursday night and Friday morning, and those gais are expected to spill over into Friday's open outcry session on the CME Group floor Friday.

Early calls for the grains are corn 1-3 higher, soybeans 3-5 higher and wheat 2-4 higher, according to private sources.

In the overnight session, March corn traded 1 1/4 cents higher at $6.18 3/4 per bushel, March wheat was 3 higher at $6.24 3/4 and January soybeans were 3 1/4 higher at $11.65 1/2, according to Barchart.com.

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Pre-holiday positioning could send the grains into the red Friday, as traders settle up ahead of the long Christmas holiday weekend. But, traders say the South American weather stress -- a bullish factor to the grains -- will likely prevent any major losses.