The snow was falling right on schedule for the 1980s in Alaska’s largest city on Monday.
Back then my hunting logs invariably marked Oct. 10 as the day the waterfowl season entered its death throes. Either snow or ice would be speeding the departure south of all but a few hardy mallards that hang on in the Southcentral part of the state all winter.
Over time, this nice predictability began to fade and the new millennium seemed to be ushering in a warmer Anchorage.
The change peaked as 2019 drew to a close. On New Year’s Eve of that year, the view from the top of the Hotel Captain Cook in downtown Anchorage was more Seattle than Anchorage with rain washing snow-free, 45-degree downtown streets.
That scene brought to an end Alaska’s warmest year on record after a string of unusually warm years. It was easy then to believe the 49th state had already started to transition into a new, globally warmed normal.
December 2017 had gone into the record books as a whopping 7.5 degrees above normal in Anchorage. December 2018 says the Alyeska Ski Resort in Girdwood, just down the road from the state’s biggest city, shut down by rain.
The 1,000-mile Iditarod Trail Sled Dog Race across the wilds of Alaska needs cold to freeze the lakes and rivers the trail crosses and follows plus snow to bury rocky mountain passes. There were dire predictions it might fall short of both.
The cooldown started in 2020, and since then the 49th state has slid back to something closer to the old normal than the new normal.
Monday came a lovely white demonstration of that old normal and an illustration of the wide annual variations in weather in the north despite a steadily warming planet.
On a micro level, we now know what produces the weather shifts. In this case, it was as simple as a cold front moving in from the north to collide with a low-pressure moving east along the northern edge of the Gulf of Alaska.
On a macro level, however, meteorologists are still a long way from sorting out how these pieces move on the global stage. They do have models to help them make forecasts, but the models are often at odds with each other.
As this was written, the National Weather Service was observing that for the next few days the “forecast confidence remains around average….Models generally have a similar trend though there is disagreement with respect to the fine details.
“A low is expected to move north across the Gulf of Alaska and into the Southcentral Alaska Wednesday evening. There is disagreement with respect to how far west the precipitation associated with this low will reach.
“For now the NAM/GEM further east solution is favored due to cold air across Anchorage, the Mat-Su and Kenai Peninsula likely to help keep this low farther to the east.”
NAM is the acronym for the North American Mesoscale Forecast System, a complicated computer model built by the National Centers for Environmental Prediction. The model is loaded up with all sorts of data and spits out its best guess as to what it means.
There are other models. The GEM – formally the Global Environmental Multiscale Model – is basically the Canadian version of the NAM. And then there is the European Centre for Medium-Range Weather Forecasts (ECMWF), and a laundry list of others – ICON, GFS, GEM, UKMO, ACCESS-G, ARPEGE, CMA, GDAPS/UM – developed by scientists from a variety of countries.
Unless, of course, you are an American and then it’s likely vice-versa with the GFS (Global Forecast System) the most accurate and the European Union’s ECMFW just behind.
The GFS “generates data for dozens of atmospheric and land-soil variables, including temperatures, winds, precipitation, soil moisture, and atmospheric ozone concentration. The system couples four separate models (atmosphere, ocean model, land/soil model, and sea ice) that work together to accurately depict weather conditions,” according to the National Oceanic and Atmospheric Administration (NOAA).
Or at least, in theory, it works to accurately depict weather conditions.
In reality, NOAA admits that “a seven-day forecast can accurately predict the weather about 80 percent of the time and a five-day forecast can accurately predict the weather approximately 90 percent of the time. However, a 10-day – or longer – forecast is only right about half the time.”
The problem is with all of those pieces moving on the board. The models now have the ability to make a pretty good prediction of where the nearest ones are likely to end up, but for those far away?
And it’s there that things get tricky in predicting what exactly climate change will produce in terms of weather.
It’s easy to understand why some people are skeptical. It was easy to be skeptical in Anchorage on Monday with the temperature hovering near freezing and the snow flying.
Just as it was easy to be troubled if you were a climate-change worrier in Anchorage in June when the city saw a week of temperatures above 70 degrees and wildfires erupted in an equally warm Western Alaska.
By then, however, the Alaska summer was already underwater and many were wishing they could reboot June. It was not to be. August and September were more near normal.
The old normal that is and a long way from the new one. The maximum temperature in September never got above 63, according to the National Weather Service, and it rained on 22 days.
The mean temperature for the month did end up a degree above normal, but the seemingly constant rain made that easy to miss.
And now comes the snow.