CBOT wheat hits July high on declining Russian crop estimates

* Wheat prices tick up on weather woes in Black Sea

* Soy falls on strong global competition, US plantings

* Corn falls on technical trading

CHICAGO, May 21 (Reuters) - Chicago Board of Trade wheat futures reached their highest level since July on Tuesday as frost damage in top-exporter Russia and lower U.S. crop ratings supported prices, traders said.

The market temporarily extended gains above $7 per bushel following a 6% rise on Monday.

IKAR agricultural consultancy cut its Russian wheat crop forecast to 83.5 million metric tons from 86 million tons and lowered its projection for 2024/25 Russian wheat exports to 45 million tons from 47 million tons.

"There's still uncertainty over the size of the crop," said Mark Schultz, trader at Northstar Commodity.

The U.S. Department of Agriculture (USDA) lowered its U.S. winter wheat crop condition rating to 49% good to excellent in a weekly crop progress report issued after trading ended on Monday, down one percentage point from a week ago and two points below the average estimate gathered by Reuters.

In Ukraine, a major wheat and corn exporter, a state weather forecaster said recent frosts had not caused significant damage to grain and oilseed crops.

CBOT July wheat climbed 8-3/4 cents to $6.97-1/2 per bushel. CBOT July soybean futures closed 11-3/4 cents lower at $12.36-1/4 per bushel and CBOT July corn fell 2-1/2 cents to end at $4.58 per bushel.

Corn prices ticked down on technical trading and rapidly advancing U.S. plantings that also weighed on soy futures, traders said. The USDA reported 70% of the U.S. corn crop and 52% of the soybean crop were planted as of Sunday.

"The planting progress for all crops was further along than what the trade was expecting," Schultz said.

Chinese importers are believed to have purchased at least two shipments of soybeans from the United States in the past few days, grain traders said.

But weak soymeal prices added pressure on soybean futures, traders said. The competitiveness of U.S. soymeal on the global market remains in doubt as Argentina is expected to start crushing increasing amounts of soybeans. (Reporting by Heather Schlitz. Additional reporting by Naveen Thukral; Editing by Marguerita Choy and Susan Fenton)