Ag Weather Forum

Spring 2013 will be noted as a season of historic cold. The National Oceanic and Atmospheric Administration (NOAA) recently noted that the month of April was the second-coldest since 1895. That trend has continued into early May.

It's not unusual for cold periods to occur during spring. After all, "Spring is not a mild season," said South Dakota state climatologist Dennis Todey. "It's a transition; a see-saw between warm and cold. Typically, we have cold outbreaks that last a short while, and then it turns warmer."

Not in 2013, however. DTN senior ag meteorologist Mike Palmerino believes a pronounced development of robust high pressure in the Arctic Circle near Greenland was the cause of the sustained cold regime we are now in.

"That high-latitude blocking set up in mid-February and helped to force very cold air south," Palmerino said. "Another major effect of this pattern was the heavy snow cover which moved into the Canadian Prairies and the northern Plains."

This atmospheric feature is still around. In fact, its presence accounts in part for the heavy precipitation in the Plains and western Midwest this week. "We're seeing the block re-orient into the northeastern U.S., and that has stalled out the storm system over the central part of the country this week," Palmerino said.

The duration of this blocking high pressure pattern is hard to estimate accurately. Its influence is one of the key weather "drivers" that will come into play during the end of spring and into the summer season.

"The blocking high pressure, and the drought we still see in the southwestern Plains; how they influence conditions and interact will be very important for crop weather patterns," Palmerino said.

Bryce

I'm on Twitter @BAndersonDTN

(CZ/SK)

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