Weather “normal,” or something akin to it, returned to south coastal Alaska over the weekend with snow on the ground and cold in the forecast, but to the north and to the west conditions remain as odd as in the ridiculously warm year of 2019.
Arctic sea ice is growing ever so slowly in the Beaufort and Chukchi seas off the state’s northern coast, according to the National Snow & Ice Data Center, and sea surface temperatures in the Gulf of Alaska remained unusually warm.
What this all means for the winter ahead is the source of considerable scientific speculation.
The National Weather Service’s Climate Prediction Center is expecting the Arctic to remain warm for the next three months, but is calling for below normal temperatures and less than average snow along the Gulf of Alaska coast from the Alaska Range south through the Panhandle.
The prediction is largely premised on La Nina (the opposite of El Nino) conditions bringing a flood of cold, deep ocean water north along the North American coast into the Gulf.
It is expected to eventually deliver old-fashioned winter weather to the 49th state’s urban core after a string of winters where conditions were sometimes more Seattle like than Anchorage like.
Well, Judah Cohen, an authority on the Arctic oscillation and the polar vortex (PV), blogged this at Atmospheric and Environmental Research on Monday:
“Comparisons to 2011 seem to keep coming up and if it snows the end of the month here in Southern New England, that will be yet another eerie similarity to 2011. There was no significant weakening of the PV that winter and North America was very mild that winter, though Eurasia experienced widespread below normal temperatures.”
Alaska, meanwhile, got a wild ride.
First came the snowpocalypse assault on Western Alaska with hurricane-force winds bombarding villages with sideways snow and pushing tides inland to flood them. That was followed by the coldest January in Alaska history.
Meanwhile, the residents of the state’s urban core spent most every day shoveling as the snow kept coming and coming and coming. By the time it stopped, Anchorage had measured a record 133 inches – or about 11 feet.
Thankfully, Cohen added this to his ruminations:
“Though to be clear I am not expecting a repeat of the 2011/12 winter, at least not yet.”
But even a pale shadow of the winter of 2011-2012 would likely come as a shock to residents of the Anchorage Metro area grown accustomed to mild winters after a long string of them.
Who can forget how the year 2019 drew to a close in the state’s largest city with 45-degree temperatures and rain splattering snow-free city streets. It was a warm end to the warmest year in Alaska history.
By the next day, however, snow was falling. It piled up almost two-feet deep in places as the snow season finally settled in a couple months late. The weather ever since has been more of what is expected in the region.
The first snowfall this year came on Oct. 18, only three days later than the historic norm for that event, and the ground has been freezing on schedule.
The forecast for the week ahead has night time temperatures dropping to zero by Friday, a temperature that didn’t arrive until January in the winter past.
One would expect all that warm water still offshore in the Gulf to help keep temperatures higher, but that doesn’t appear to be the case. Cohen readily admits the difficulty in trying to sort out climatic patterns.
“While Colorado is experiencing record wildfires,” he noted, “they also got hit by record cold and a foot and a half of snow! And some of the record cold in the Western U.S. is not only daily records but even all-time monthly records. Maybe to me the most impressive chart is the rapid advance of North American snow cover this month, which is likely unprecedented. And if you juxtapose the record cold and snow in the context of the continuous record warmth observed throughout the Northern Hemisphere this past spring and summer, the record cold is even more impressive.”
And, of course, the source of that cold – the Arctic – “continues to experience record warmth and record low sea ice that is continuously heating the atmosphere from below,” Cohen wrote.
“I saw on Twitter that climate change is understood to result in greater variability or large swings in the weather (and who doesn’t believe what they read on Twitter?). But this is not what the models predict with climate change but rather the opposite with damped variability or a decrease in weather volatility.”
Feel free to scratch your head here. As Cohen concedes, “the weather whiplash from record heat to record cold is not simple or straightforward. So what changed from September when warmth was nearly universal and snow and ice were at record lows to October where snow is record extensive and cold is intense and expansive across North America at least?”
The obvious answer was that prior to September the Arctic was still sucking up heat from the sun. The opposite of that is underway now. The heating is flowing out of Arctic waters into the atmosphere.
“To my eye, it is Occam’s Razor,” Cohen writes. “The record warmth in the Arctic is related to the record cold across North America. Of course, this is a controversial topic and the opinion I express here is probably the minority opinion where the majority opinion is that a warm Arctic contributes to a warmer and not colder mid-latitudes.”
That said, more than a few Alaskans have probably noted the connection between warm weather in the 49th state, and cold weather from out of the Arctic tracking the path of the Wisconsin Glaciation down into the U.S. Midwest or what some in Minnesota would like to rebrand as the new “North.”