America's parched hard red winter wheat crop may face something of a make or break week, potentially receiving up to 20 inches of snow – which it will need to protect it from a follow-up freeze.
Weather models have "changed dramatically overnight", placing a "major winter storm" on the agenda for the US Plains early next week, veteran meteorologist David Tolleris said.
The storm, which "will easily be one of the biggest" of the winter, looks set to dump up to 10-20 inches of snow on a swathe Oklahoma, eastern Colorado, northern Texas and Kansas, America's top wheat-growing state, where a dearth of moisture has set back winter seedlings.
"I don't know if it is crop-saving moisture, but it will certainly help," Mr Tolleris, head of WxRisk.com, said, estimating the snow at equivalent to some 1-2 inches of rain.
However, the danger is if the snow does not fall as deeply as weather models suggest, leaving crops exposed to temperatures which could fall below zero degrees Fahrenheit, or in Celsius terms to -18 degrees or more.
"That would really destroy the crop. It's a really big deal," Mr Tolleris told Agrimoney.com.
Winter wheat sowings in Kansas and Oklahoma alone totalled 14.2m acres, or more than one-third of the national total, official data earlier this month showed.
However, the weather prediction, echoed in a forecast from Meteorlogix of "temperatures near to below normal Sunday, below normal Monday, below to well below normal Tuesday" in the central and southern Plains, was deemed overall as likely good news for growers.
"This is a beneficial development and is pressing wheat lower," broker US Commodities said.
Wheat for March delivery closed down 2.2% at $9.14 ¼ a bushel in Kansas, which trades the hard red winter variety over which dryness fears have centred.
In Chicago, which trades soft red winter wheat, the March contract ended 2.4% lower at $8.26 ½ a bushel.