COLD AIR A THREAT TO SOME U.S. HARD WHEAT AREAS A cold air mass working its way south from Canada may pose a threat to developing hard red winter wheat in Oklahoma, according to Eugene Krenzler, wheat specialist for the Oklahoma Cooperative Extension. "There is some threat. Some of the crop is far enough along so that it's probably vulnerable," Krenzler said. Accu Weather meteorologist Dale Mohler said cold air moving from the north could put temperatures in the middle 20's fahrenheit as early as tonight, depending on development of a low pressure area over southeast Colorado which could stall the system. If impeded by the low-pressure area, the cold air could hit Oklahoma and Texas as late as Monday morning. Temperatures could stay in the mid-20's for up to eight hours, Mohler said. Krenzler said less than 10 pct of the Oklahoma wheat crop has advanced to boot stage. The closer to that stage the more vulnerable the head of the wheat is to cold weather, he said. "We can handle probably an hour or so down to 25 or 26 degrees (fahrenheit)," Krenzler said, "as long as we don't have a lot of wind." "If we do get six hours down below 25 degrees I'd say we have a good chance of significant damage to the heads," he said. Krenzler said early planted stands in the north-central and southwestern parts of the state are probably most vulnerable. Crops in the panhandle of Oklahoma and Texas are less developed and have some snow cover protection from the cold, he noted.