Well, if you’ve been grumbling about it feeling cooler than usual in Alaska this spring, you’re right.
Lingering snow and cloudy days resulted in temperatures about 3.5 degrees below average, statewide, from March through May.
National Weather Service climate researcher Brian Brettschneider — back for our Ask a Climatologist segment — says that ranged from about 1 degree below average in Juneau, to 2 or 3 degrees in Anchorage, and 4 or 5 degrees in Fairbanks.
And Brettschneider says April was a particularly chilly month statewide.
Brian Brettschneider: It was the month where, normally, April is where we transition to spring. But April really was a continuation of winter. So statewide, it was either the fourth or fifth coldest April on record, about 10 degrees below normal. But in much of the central and western Interior, it was, you know, 14 to even like 18, 19 degrees below normal for the entire month, which is really remarkable. And even places like Nome set an all-time lowest temperature record for the month of April. A lot of records were set in (the) western part of the state.
Casey Grove: Interesting, yeah. So a lot of people were complaining about that, obviously. Maybe this is a dumb question, but is that just because of cloud cover, like it just happened to be cloudy, more of the time?
BB: You know, spring is tough, because as we get the sun getting much higher in the sky, particularly from mid-April onward, the temperature can be highly dependent on if there’s still snow on the ground. So snow, in many ways, acts like a mirror, it reflects a lot of the solar energy back into space. So if there is snow in the ground, it’ll be cooler than the airmass would otherwise let it get to. So because we had a deep snowpack in many parts of the state, it becomes what’s called a “positive feedback cycle.” We get some below-normal weather, and then that prevents the snow from melting, and the fact that the snow didn’t melt means that it keeps the weather cooler than it would ordinarily be. So from an atmospheric point of view, we just had a big area of very persistent low pressure that was really stuck over the state and the Bering Sea area, and that just prevented any kind of any warm air from moving over the state.
CG: Gotcha. Well, so how does this spring compare to years past? I mean, some of those numbers sound pretty significant, but in the grand scheme of things, are they?
BB: Yeah, so, you know, when we compare March, April, May 2023 versus other years, we’re going to look back and say, “Yeah, this was cooler than the normal for the current normal period,” which is 1991 to 2020. But historically, this would be actually pretty typical spring conditions. So we do have some recency bias to overcome. But we’ve certainly had some much colder springs in years past.
CG: Yeah, no kidding. I feel like we talk about this a lot, too, where what’s going on right now, or even this past spring, doesn’t really mean a whole lot, you know, in the long-term summer forecast. And I should say, I feel like we talk about that in regards to wildfires, too, because it doesn’t take a whole lot of hot, sunny, dry days to really ramp up that wildfire danger. So just to like, make that point.
BB: And to follow up on that, as many people in, say, the Fairbanks area remember, 2004 was kind of the wildfire season of record. Well, May of 2004 was the wettest May that Fairbanks had. Anchorage people remember the hot summer of 2019 and that we were just choked in smoke basically that entire summer. May 2019 was the wettest May on record in Anchorage. So we can get lulled into thinking, “Oh, well, boy, it’s really wet and cool,” and kind of try to extrapolate that as to what the summer conditions will be, only to be completely wrong.
CG: So is that forecast for June to be warmer than normal, is that based on shifting into an El Niño pattern?
BB: So there’s a couple of things that they look at when making these monthly and seasonal outlooks. And one is they do look at what are called “dynamic models.” That’s kind of, “Here’s the initial conditions, and where do we expect it to evolve over the next number of several weeks to several months.” So that’s one aspect. Another is they do look at trends, and trends and temperatures, and trends and, say, sea ice, and trends and ocean temperatures and how that would affect (the outlook). And then they also do look at El Niño or La Niña conditions. Typically in an El Niño summer, Alaska is a little bit warmer than normal. And particularly the western part of the state has a stronger signal for warmer-than-normal conditions. So all those things go into the pot when they generate a monthly and a seasonal outlook.
CG: OK, well Brian, now I want to play the part of the, you know, cranky Alaskan who felt like their spring was really, really cold and maybe, you know, just to understand that I’m just trying to play a character here. But doesn’t that mean, since it was, in some places, significantly colder than normal, doesn’t that mean that global warming is not actually happening?
BB: Well, it can be tempting to look outside and, you know, while you have your jacket on and are maybe even looking at snowflakes falling in summer to say, “Well, what happened to global warming?” But we have to remember that we are, even though we’re a big state — the biggest, of course — we are a small part of the globe. And most of the globe is really on fire, in many cases literally, especially in Canada. And right now, all the buzz in the climate community is how the oceans are basically just on fire. How Antarctic sea ice is, even though they’re in 24 hours of darkness, is decreasing, day after day, not increasing. It’s really uncharted territory. So we’re a little area of cool nirvana compared to everyone else.