*

Hot, dry weather forecast for Russia, Ukraine in coming

months

*

Flooding in U.S. Midwest shuts rail lines, floods grain

bins

*

Relief seen for China's corn, soybean crops hit by

heatwave

*

India set for normal weather, Australia seen getting more

rains

(Adds flooding in U.S. paragraphs 10-14)

By Naveen Thukral and P.J. Huffstutter

SINGAPORE, June 24 (Reuters) - Forecast dryness in the

Black Sea region's breadbasket is likely to stunt sunflower and

corn yields, while heavy rain in the U.S. after near-record

temperatures threatens to take a toll on crops, squeezing world

supplies and pushing prices higher.

"The weather forecast for the Black Sea region is a big red

flag," said Chris Hyde, a meteorologist at U.S.-based Maxar,

with dryness and below-normal rains expected for July and August

likely to crimp the region's key corn and sunflower crops.

Record temperatures in major global growing regions have

delayed planting and hurt developing crops as the impact of

climate change intensifies, with vast swathes of farmland in

Russia, China, India and parts of the United States experiencing

extremely hot conditions and below-normal rainfall.

Global wheat prices jumped to a 10-month high in May

after adverse weather trimmed yields for the maturing crop in

Russia, the biggest exporter.

Hot weather in southern Russia will hit crops because of a

lack of soil moisture, with lower precipitation and heat also

expected in Urals, Western Siberia and Transbaikalia, Russia's

Hydrometeorological Centre said in a forecast.

Southern and eastern Ukraine have also seen hot and dry

weather, with precipitation between May 1 and June 10 only

20-50% of normal, according to the state weather forecaster,

with drought hindering development of winter and spring crops in

parts of the Kharkiv and Donetsk regions.

"The month of May in Ukraine turned out to be one of the

driest for the last 30 years," state forecasters said. "In

northern regions, in particular in Zhytomyr, hail resulted in

damage of spring crops such as corn, soybeans and sunflower."

In the U.S., a top food exporter, intense heat has gripped

parts of the east coast, causing the government to reduce the

percentage of corn and soy rated good and excellent on Monday.

Excessive rains in the key Midwest growing region and forecasts

for more wet weather have raised fears of floods.

"In the Midwest, the focus is shifting from heat to too much

rain, which could result in flooding on corn and soybean

producing areas, especially in the Upper Midwest," Hyde said.

Iowa governor Kim Reynolds said on social media platform X

that widespread flooding in northwest Iowa, the top U.S. corn

producing state, had pushed river levels above 1993 records.

BNSF railway, owned by Berkshire Hathaway ( BRK/A ), said in

a statement a bridge collapsed over the Big Sioux River on

Sunday and it is rerouting trains through Creston, Iowa. Union

Pacific ( UNP ) said it closed rail lines between Mason City, Iowa, and

St. Paul, Minnesota, and between Sioux City, Iowa, and St. Paul.

Rob Jacobs, chief executive officer of Cooperative

Farmers Elevator, said severe flooding impacted several of the

cooperative's locations, with roads washed out and feed mill

facilities swamped. Tunnels used to load grain bins flooded and

warehouses used to store seeds and farm chemicals filled with up

to 18 inches of water, Jacobs said.

Most analysts said it was too early to estimate

potential crop damage from flooding.

CHINA, INDIA WEATHER SEEN IMPROVING

In Asia, ample rains are expected to alleviate severe

dryness in parts of China, a top soybean buyer, while rains

during India's monsoon, running a fifth below normal, are likely

to recover, boosting agriculture in the world's biggest rice

exporter and top edible oil importer.

"China's corn and soybean producing north and east has been

dry and a worry," said Hyde. "But the weather is expected to be

normal to slightly above normal precipitation in the

July-September period, which will be beneficial for crops."

China's meteorological centre told Reuters that parts of the

north, northeast and western provinces will see higher

precipitation in July to September, which will encourage crop

growth.

"But the precipitation will be intense in some areas, there

will need to be vigilance about rapid shifts in droughts and

floods," it said, adding that the higher humidity may also raise

the risk of crop diseases and pests.

In India, the monsoon is advancing after stalling for more

than a week, a weather department official said.

"It has now gained much-needed momentum for its advance into

the northern plains. In the next few weeks, we expect several

spells of heavy rainfall that will erase the rainfall deficit.

July is shaping up to be promising."

The weather in Australia is expected to be normal, with some

areas getting higher than average rains, boosting the wheat crop

outlook, while mainly normal weather is also forecast in coming

months in Argentina and Brazil.