By Sam Nelson
CHICAGO (Reuters) - Torrential rain and flooding from Tropical Storm Isaac will bring relief to a large chunk of drought-stricken cropland but will stall early harvest of corn, soybeans and rice, an agricultural meteorologist said on Tuesday.
Isaac was near hurricane force as it bore down on the northern U.S. Gulf Coast. It was expected to make landfall in the New Orleans area, seven years after the city was devastated by Hurricane Katrina.
"It will barrel first into southeast Louisiana and southern Mississippi leaving one and a half feet or more of rain, and three to five inches or more in the central and southeast Midwest," said Don Keeney, meteorologist for MDA EarthSat Weather.
He said the downpours would bring welcome moisture ahead of fall seeding of the U.S. winter wheat crop. But mature corn, soybeans and rice, already weakened by the worst drought in over 50 years, could suffer substantial further losses from high winds, heavy rains and localized flooding. He also said wet conditions could lead to crop diseases.
"There won't be much rain in the north, such as northern Illinois, Michigan or Wisconsin, but two to three inches will be the norm, with up to four inches elsewhere in areas such as central and southeast Missouri, central and southern Illinois, Indiana and Ohio," he said.
Early plantings of crops and a summer of relentless heat and drought pushed crops to maturity, leading to a record or near record early start for harvesting.
The U.S. Department of Agriculture (USDA) on Monday said 6 percent of the U.S. corn crop had been harvested and 26 percent of the crop was mature, most of that in the U.S. South and in the path of the expected torrential rainfall.
USDA said 8 percent of the soybean crop was dropping leaves or mature, and rice harvest was 27 percent complete. It said 24 percent of the U.S. cotton crop bolls were open and ready for harvest.
Isaac was located about 105 miles southeast of the mouth of the Mississippi River Tuesday morning, with top sustained winds of 70 miles per hour. It was moving northwest at 7 mph.
The storm was more than 400 miles wide. Craig Fugate, director of the Federal Emergency Management Agency, said the worst effects may be in Mississippi and Alabama.
(Reporting By Sam Nelson; editing by John Wallace)