The grains look to start the week before Christmas on a positive note, with corn, soybeans and wheat called to open Monday's trade higher, sources say.

Overnight trading saw the grains heading sharply higher: Nearby corn was 12 1/2 cents higher at $5.95 1/2 per bushel, while nearby soybeans were 17 cents higher at $11.47 and nearby wheat was 9 1/2 higher at $5.93, according to Barchart.com.

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It's likely going to be a slow trading week, as is typically the case in the week leading up to Christmas. But, what trading does go on will be focused on the hot, dry crop weather in South America, according to ICAP Energy LLC Derivatives Manager Scott Shellady.

"Hot and dry in South America. I'm sure you all knew that already but in the interest of being on top of things, I have to state the obvious," he said Monday morning. "Quiet holiday week markets are also difficult sells."

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