Newsflash: It’s cold. And those frigid temperatures aren’t going away anytime soon.
The cold has set in across most of Alaska and set daily record lows in places like Homer, King Salmon and Bethel.
It’s relatively early to be seeing such cold, says National Weather Service climate researcher Brian Brettschneider, back for our Ask a Climatologist segment.
Brettschneider, who revels in the cold, says that in the current global climate situation, it’s also much more exceptional to be setting low temperature records.
The following transcript has been lightly edited for clarity.
Brian Brettschneider: So that’s true everywhere. But it’s especially true along coastal areas where there’s been a notable warming of the water. And so when you have a big body of water right next to you, that’s warmer, it makes it doubly hard to set (low) temperature records. So, you know, that’s why places like Cordova and Homer and Kodiak, other places along the southern coast, and then the western coastal places like Nome and Kotzebue, it’s just harder to set those low temperature records when you’ve got this notably warmer body of water right next to them. But what’s different this time is, for the first time in about a decade, we’ve seen the waters around the state actually a little bit cooler than normal. And that’s been a real big shift, that is wildly divergent from what we’ve seen for the last really the last decade.
Casey Grove: Let’s back up just a little bit, though. What actually is going on to make it cold over basically like the whole state, it seems like?
BB: Well, the way in Alaska we get cold air masses to develop is you get a big area of upper level low pressure. And if you can get clear skies, it really maximizes the transfer of heat from the lower elevations up through the atmosphere. So you can literally just get rid of the warmth at the surface. And so that’s what we’ve had, we’ve had this this big upper level low pressure, you know, just parked over the state for a couple of weeks. And it’s going to stick around, you know, for at least another week and a half and maybe longer.
CG: OK, so you started to answer my next question, and I think the one that a lot of people have is, how long is this going to last? And it sounds like for a little bit longer, at least.
BB: You know, what we see over the years is that when we get into these kind of deep cold patterns is that they are really persistent. It’s not common that you have a two- or three-day cold snap. We are much more likely to have an extended cold snap that that lasts several weeks. And that’s certainly what we have. Now we had this kind of set up around maybe the 10th or 12th of November. So we’re about 10 days in and, you know, maybe another 10-plus days to go. So that would be three weeks at a minimum.
CG: We talked a little while ago about this forecasted La Niña this winter, that there was a prediction for La Niña. And it’s been fairly cold, and I guess I wonder at what point can we say: Yes, this is a La Niña winter?
BB: That’s a that’s a tricky question, because La Niña winters are generally colder and drier, but they’re also marked by high variability. So for example, our warmest winter on record, statewide, was a La Niña winter. So you can really have anything, but the scale is tilted toward cold. That said, the highest correlations with the cold in a La Niña are typically later in the winter, like January, February, March. So we’ve had this really kind of classic La Niña setup much earlier than is typical for these events. So, so far, you know, we were locked into the La Niña. But again, lots of variability and we may be above normal for two or three weeks in a row. And you might ask: Well wait, I thought we were in a La Niña winter? And my response would be: Hey, there’s a lot of variability in La Niña winters and, you know, we really need to wait until the end to see: Where were all the above normal and all the below normal days? When we add them all together, where do we end up at?