No, this is not about Sarah Palin. It’s about “La Nina,” the girl who brings the cold north to Alaska.
One couldn’t tell it on Saturday along the flanks of the Chugach Mountains where the high, muskeg swamps had more water and mud than ice – an oddity for the Southcentral region in mid-October – but the national Climate Prediction Center is promising this will change.
An on-again, off-again push of cold water north along the coast of North America appears to be on again, the center says.
And because of that it is calling for a 70 percent chance of a usually cool La Nina (the opposite of the usually warm El Nino) through the fall with a 55 percent chance La Nina will persist through winter 2016-2017.
What exactly does that mean for Alaska weather?
Well, what is known for sure at the moment is that the waters in the equatorial currents that have significant influence on West Coast weather from Mexico north to Alaska are cooling, but it’s really sort of anyone’s guess as to what will happen going forward into November and December
La Nina fallout, like that from El Nino, isn’t all that predictable to begin with in terms of snow and ice, and this La Nina sounds like a bit of a baby.
“The multi-model averages favor borderline Neutral (to) La Nina conditions persisting during the northern hemisphere fall and continuing into the winter,” the climate center says. “Because of the recent cooling in the Nino-3.4 region and signs of renewed atmospheric coupling, the forecaster consensus now favors the formation of a weak La Nina in the near term, but becomes less confident that La Nina will persist through the winter.”
So there you have it for coastal Alaska. Maybe less Seattle like than last winter, and then again maybe not.
Generally, National Weather Service meteorologist John Papineau concluded after an exhaustive study of winters from 1954 to 2000 “La Nina winters produce below normal temperatures across the entire state. The amplitude of temperature anomalies is largest in the Interior where the oceanic influence is minimal and radiational cooling is large.”
Papineau noted that both shifts in the jets stream (it flowed south to north a lot over Alaska last year, bringing in warm air from south near Hawaii) and those “oceanic influences” could have as much or more influence on coastal Alaska weather than La Nina or El Nino.
Weather geeks can have a blast trying to sort this all out.
“There are two features to watch in the Pacific Ocean this fall and winter,” the Northwest Farm Credit Service noted in its October crop report. “First is the warm pool of water south of Alaska. These warm waters will impact the position and strength of the jet stream. Second, the weak La Niña forming in the central Pacific is correlated with cooler and wetter winter conditions. This will compete with the warmer ocean temperatures south of Alaska.”
That warm water south of Alaska is near the bottom of the Alaska Gyre, which spins the water of the Gulf of Alaska counter-clockwise as if in a big washing machine. Coming off the Gyre, the Alaska Current grabs water as far south as the Queen Charlotte Islands of Canada and moves it north to Alaska along the coast of the Panhandle, past Prince William Sound and around to Kodiak Island.
All the warm water out there along the Gyre now might serve to mute any La Nina changes for Alaska if, of course, the on-again, off-again La Nina is really, truly, seriously on again.
As Emily Becker writes at the Climate Center’s El Nino Southern Oscillation (ENSO) blog, the conditions of the moment “all add to a new La Nina watch:
“El Niño and La Niña are seasonal phenomena, meaning that these specific conditions have to be present for several months in a row. There can be short-term fluctuations in the winds, pressure, and so on, but the average over the several months must be consistent. This is why ENSO is considered a seasonal climate, not weather, phenomenon.
“So we’ll watch the tropical Pacific closely over the next month, to see if the suggestions of La Niña that showed up in the second half of September are here to stay.”
That said, the National Weather Service in Anchorage is predicting the arrival of the first snowflakes of winter any day.
A Friday forecast that had Sunday snow on the horizon was Saturday rolled back to a 20 percent chance of snow showers on Sunday night and a 30 percent chance of snow on Tuesday night before temperatures climb back into the 40s and the chances of rain increase.
Daily highs are forecast to be in the 39-42 temperature range through Wednesday. Those highs are what would normally be seen about a week earlier in October as Alaska’s largest city starts the slide into winter.
Over dinner Saturday night, Ellis Conklin, a once semi-famous reporter for the now gone Anchorage Times newspaper on his first visit back to Anchorage in 35 years, remarked that he’d never seen an Anchorage quite like this.
It was odd, he said, to look out his hotel room window in mid-October and not see the tops of the Chugach Mountains cloaked in a heavy coat of white. His was a memory of the old Alaska. The new one is clearly different.
This ain’t your grandpa’s 49th state anymore.
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