* Freeze damage to wheat in Kansas, Oklahoma and Texas
* Moisture valuable for drought-stricken areas
* Wet and cold weather delay spring corn plantings
By Sam Nelson
CHICAGO, April 11 (Reuters) - A cold snap the past two mornings probably harmed the winter wheat crop in the southwest U.S. Plains, while wet weather added valuable moisture to drought-stricken areas but also stalled corn seedings, an agricultural meteorologist said on Thursday.
"It dropped down to 18 to 22 degrees (Fahrenheit) in the western quarter of Kansas and the northwest Panhandles of Texas and Oklahoma," said John Dee, meteorologist for Global Weather Monitoring.
"Bottom line is there could have been damage to wheat in the jointing stage, but it will take some time to find out," he said. Dee said warmer weather would now move into the Plains States, and drier weather was expected over the next 10 days.
However, wet and chilly weather is expected to continue in the U.S. northern Plains and Midwest over the next 10 days to two weeks, which will stall spring fieldwork, he said.
"It's getting close to when they would like to plant corn, but there won't be a whole lot of fieldwork for the next 10 days," Dee said.
Agronomists said wintry weather this week probably damaged a portion of the hard red winter wheat crop in Kansas and Oklahoma, two top U.S. producers of the grain.
"At this stage, it is certain that we will have some freeze injury to the majority of the Oklahoma wheat crop, but it will be a good seven to 10 days before we can accurately assess the level of injury," Oklahoma State University small grains extension specialist Jeff Edwards wrote in a blog post on Wednesday.
Jim Shroyer, Kansas State University extension agronomist, also said it was possible that the cold weather had harmed some of the Kansas crop.
But U.S. farmers are welcoming the April showers after the worst drought in more than 50 years trimmed last year's harvests and has been stressing the winter wheat crop.
The U.S. Department of Agriculture on Monday said 36 percent of the U.S. winter wheat crop was in good to excellent condition, up from 34 percent a week ago but well below the year-ago rating of 61 percent.
The drought has taken a toll on the winter wheat crop that has broken away from its winter dormant or hibernation status and is now growing, leaving it vulnerable to harm from cold weather or another spate of dryness.
Drought conditions are retreating slowly in the U.S. Plains, according to a report issued last Thursday by a consortium of state and federal climatologists.
Don Keeney, meteorologist for MDA Weather Services, said that at the end of March, 6 to 8 inches (15 to 20 cm) of rain were needed to bring soil moisture levels back to normal in much of Nebraska and a corner of northeast Kansas.
Keeney said 2 to 4 inches (5 to 10 cm) were needed in the balance of the central Plains and western Iowa.
The Drought Monitor report, which tracks the U.S. land area stricken by drought on a weekly basis, said the Plains region, which has been the hardest hit, was seeing improvement because of rains and snow in the past two months. (Additinal reporting by Julie Ingwersen in Chicago; Editing by Lisa Von Ahn)