FARGO — The cause of the persistent cold weather that has kept North Dakota and Minnesota shivering amid below-normal temperatures could lie far away in the churning waters of the northern Pacific Ocean.
Paradoxically, a mass of abnormally warm water off the Pacific coast appears to be disrupting the jet stream in a way that — more often than not in recent months — has funneled colder-than-normal air over the Northern Plains and Upper Midwest.
Some call the disruptive mass of warm water “the blob.”
That appears to be the likely explanation for the persistently cold weather in the region at a time when much of the globe, including Alaska and most of the western and southern United States, has been consistently warm.
This October, in fact, was the warmest on record globally.
But certainly not in North Dakota and Minnesota.
John Wheeler, WDAY chief meteorologist, believes “the blob” could explain the cold weather that has dominated the region.
Warm water in the Pacific can cause a high-pressure “ridge” that can align the jet stream to scoop cold air from the far-north latitudes and send it swooping down upon the Northern Plains and Upper Midwest.
Ocean “heat waves” have long been influencing the weather, but their strength and duration could be increasing with ocean temperatures rising worldwide, Wheeler said.
He’s quick to add that the Pacific had a similar mass of warm water during the 2014-15 winter, which in this area was not particularly cold.
“So the warm blob does not equate to cold weather in North Dakota and Minnesota,” Wheeler said. “It’s not as simple as one thing causing another — it’s never as simple as that.”
Adnan Akyüz, the North Dakota state climatologist, agreed that the blob of warm water in the Pacific was to blame for the spell of mostly cold weather.
“That is why we have been experiencing colder-than-average temperatures,” he said, adding cold weather caused by the meandering jet stream is nothing new.
It’s important to note, Wheeler said, that in spite of the area’s recent run of mostly cold weather, this millennium so far is running mostly warm.
“We’re actually getting not more frequent cold snaps but less frequent cold snaps,” he said. “My stance is not that we’re headed for a string of cold winters here. The evidence is clearly not (pointing to) that.”
For about three years, from the fall of 2008 through the spring of 2011, the area experienced a period of mostly cold weather — but that period falls within a longer period of generally warmer weather, Wheeler said.
As for the approaching winter, the Climate Prediction Center recently issued an outlook predicting a higher probability for cold and wet weather January through March.
Current and near-term weather patterns suggest cold weather will continue through around Christmas, said Bill Barrett, a National Weather Service meteorologist.
The blob thesis “sounds pretty reasonable” for explaining the area’s persistent, mostly cold weather, he said.
Citing other weather patterns, Barrett said, “For the short term, we’re still going to be in this pattern with cold dominating.”