Dreaming of a white winter?If you appreciated last year’s warm, dry winter, thank the Arctic oscillation. But if you want the drought to end, you better hope the Arctic oscillation switches gears this winter, says Adnan Akyuz, North Dakota state climatologist.
By: Jonathan Knutson, Agweek
If you appreciated last year’s warm, dry winter, thank the Arctic oscillation.
But if you want the drought to end, you better hope the Arctic oscillation switches gears this winter, says Adnan Akyuz, North Dakota state climatologist.
“It’s very well possible the Arctic oscillation will do its trick just like last year,” though this time in reverse, he says.
Last winter, many weather experts expected a cold, snowy winter in the Upper Midwest. But the opposite was true, with winter bringing little snow and record and near-record high temperatures.
In explaining why their initial expectations where wrong, experts pointed to the Arctic oscillation, a large-scale and largely unpredictable weather pattern. The Arctic oscillation unexpectedly turned positive last winter, causing less frigid air to extend to the Upper Midwest.
If it turns negative this winter, more snow and cold would enter the region, Akyuz says.
More snow on the ground would provide another moisture source from which spring and summer storms could draw, potentially increasing rainfall next year, he says.
“Winter precipitation is very important” in priming the pump for rain next year, he adds.
Though rain fell in October across some of the region, the precipitation was too limited to recharge dry ground, he says.
Akyuz doubts any additional rain this fall would be sufficient to recharge soil moisture.
“We’re pretty much relying on winter snowfall and spring precipitation,” he says.
Predicting whether the Arctic oscillation will be negative or positive is difficult.
Here’s how the National Climatic Data Center’s website explains the Arctic oscillation and its impact:
“When the AO is in its positive phase, a ring of strong winds circulating around the North Pole acts to confine colder air across polar regions. This belt of winds becomes weaker and more distorted in the negative phase of the AO, which allows an easier southward penetration of colder, arctic air masses and increased storminess into the mid-latitudes.”