* Large Saudi wheat purchase ends lull in import demand

* Rain forecast in U.S. Midwest in focus for soybeans, corn

*

HAMBURG, June 5 (Reuters) - Chicago wheat firmed on Monday on hopes that current low prices will drive more export demand after Saudi Arabia made a major purchase in an international tender.

Corn and soybeans were little changed with forecasts of welcome rain this week in U.S. Midwest production regions.

The Chicago Board of Trade most-active wheat contract was 0.2% higher at $6.20-1/2 a bushel by 1119 GMT, having earlier hit its highest since May 17 at $6.28-3/4 a bushel.

Wheat hit 2-1/2 year lows on Wednesday as improved U.S. crop conditions and concerns over export competition weighed.

Corn rose 0.08% to $6.09-1/2 a bushel, soybeans fell 0.06% to $13.52 a bushel.

Saudi Arabia bought 624,000 tonnes of wheat in a tender on Monday, more than the 480,000 tonnes sought, with traders expecting Black Sea wheat, especially Russia's, to be heavily supplied.

“The large wheat purchase by Saudi Arabia...was encouraging as the volume bought was larger than sought originally, so low prices could be starting to create more demand after a quiet period,” said Matt Ammermann, StoneX commodity risk manager.

"But there is a perception that Russia could supply much of the Saudi purchase because of low prices being offered in export markets which is limiting rises.”

Ukraine said on Thursday the Black Sea grain export deal had been halted again as Russia had blocked ship registrations but Ukraine would be ready to continue exporting grain across the Black Sea as part of a "plan B".

Forecasts of rain and cooler temperatures for newly planted corn and soybean crops in the U.S. Midwest were welcomed.

"Crops have been suffering from dryness and the USDA U.S. Department of Agriculture) may cut its condition assessment of U.S. crops later today,” Ammermann said.

“It may be that some stress has been suffered by U.S. crops but the big picture in they seem to be growing nicely so there is no need for a major risk premium now.” (Reporting by Michael Hogan in Hamburg, additional reporting by Naveen Thukral in Singapore, Editing by Kirsten Donovan)