Climate Watch

By Rick Thoman Alaska Climate Specialist Alaska Center for Climate Assessment and Policy International Arctic Research Center/University of Alaska Fairbanks

A fascinating aspect of weather in western Alaska is how sometimes the atmosphere gets “stuck” in a particular pattern for weeks at a time, whether warm or cold, stormy or tranquil, but at other times how we seem to get “weather whiplash”, with conditions varying dramatically back and forth over the course of a few weeks. I’ve given some thought to how we might analyze “weather pattern stability” that might help us learn if these periods of “stable” or “unstable” weather conditions are changing over time. So, for the first time anywhere, here’s the Nome weekly average temperature stability analysis over the past year. This compares the average temperature departure for the past seven days against the seven-day average from the previous week.

It works like this: If today is Thursday, we compare the average temperature departure from normal since Friday to whatever the average departure from normal was for the seven days ending last Thursday. We do this every day (not just Thursdays) to come up with the graphic. Looking back to early 2023, there were repeated dramatic swings in the seven-day average temperature. For example, in the last two weeks of February 2023, temperatures went from the 20s below to slightly above freezing and then back to the 20s below.

In contrast, the cloudy weather and frequent rain of late summer 2023 show up clearly as a long period when weekly temperatures relative to normal were not changing much at all.

On the right edge of the plot, the dramatic change in the weather pattern right around New Year’s Eve shows up clearly. This kind of analysis may prove to be useful, or it might not. But if we don’t ask the questions, we’ll never know the answers. And that’s what science, western and Indigenous, is really all about: making sense of the world around us in ways that prove useful.