CHICAGO, June 16 (Reuters) - U.S. corn, soybean and wheat futures all set multi-month highs on Friday as worries about stressful dry conditions in key portions of the Midwest prompted a flurry of buying ahead of a three-day holiday weekend, analysts said.

"We have an issue here in the center of the Corn Belt (where) we can't seem to break through and get meaningful moisture," said Terry Linn, analyst with Linn & Associates in Chicago. "Temperatures are going to be on the rise next week, and so the stress is going to increase on crops that are already struggling with moisture deficits."

The U.S. Department of Agriculture in May projected record-large U.S. corn and soybean harvests for 2023, but those targets are in jeopardy due to

problematic weather as the summer growing season unfolds

.

As of 1:05 p.m. CDT (1805 GMT), Chicago Board of Trade July corn was up 16 cents at $6.39-1/4 per bushel, and new-crop December corn, representing the 2023 crop, was up 22 cents at $5.96-1/2 a bushel after rising to $5.97, its highest since February.

New-crop November soybeans were up 48 cents at $13.40-1/4 a bushel after hitting their highest since mid-March, and CBOT July wheat was up 25-1/2 cents at $6.87 a bushel.

U.S. markets will be closed on Monday for the

Juneteenth federal holiday

, keeping traders on edge as weather forecasts fluctuate.

"With a three-day holiday approaching, the actual rainfall over the weekend and the weather forecast on Monday evening will determine the price direction for the upcoming week," brokerage Copenhagen Merchant said in a note.

Wheat climbed as short-covering by investors, a setback in the dollar this week and dry weather in Europe shifted attention away from harvest progress in the U.S. Plains.

Uncertainty around the Black Sea grain deal allowing export shipments from Ukraine also lent support. Russian officials said on Friday the pact allowing shipments from Ukraine could not be extended under current circumstances when it expires in mid-July. (Reporting by Julie Ingwersen; additional reporting by Gus Trompiz in Paris and Rajendra Jadhav in Mumbai; editing by Sherry Jacob-Phillips, Subhranshu Sahu and Leslie Adler)