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Kenneth Wright: It's been very cold in Michigan over the last several days and it's only going to get more frigid. Experts say a polar vortex is making its way south from the Arctic Circle. WCMU's David Nicholas spoke with Joe DeLizio with the National Weather Service office in Gaylord to better understand what it means to be in a polar vortex and how it works.
David Nicholas: We hear the term and we know it's cold, but can you define for us what really is a polar vortex?
Joe DeLizio: Yeah, so it's basically an area of low pressure, and it's a large rotating counterclockwise sort of vortex, if you want to call it that. In the northern hemisphere, it rotates counterclockwise and typically is high in the atmosphere, several thousand feet -- tens of thousands of feet actually. And typically, it is farther in the northern latitudes, and so the jet stream kind of holds that together for the most part.
DN: Does this have any real connection with snow? Because we've all grown up with the term “storm” or “blizzard,” is this focused or centered mostly on then, just the very, very frigid temperatures?
JD: Yeah, generally it's more focused or the impacts really will be the cold temperatures when it drops south. Now you can certainly get storm systems and snow with that. For instance, we have a nice cold shot of air across the CONUS later this week into the weekend, and it's going to push really far south. And so you have the potential for some winter precipitation, even as far as the southeast, mid-Atlantic and northeast there. So certainly you can have storm systems; there has to be a little bit more than just the polar vortex at play, for that needs to be pieces of energy in the atmosphere. But certainly more specifically for up here with our lakes, if we do get a cold air outbreak contributed from that, certainly we can get our lake effects snows.
DN: How frequent do these come about? Are they like an El Nino or La Nina cycles, or is there a random nature to how often we find ourselves in a polar vortex?
JD: Yeah, a little bit of both. Certainly, El Nino is a lot more favorable for our lake-effect snows, and typically they are tied with some of these cold air outbreaks, as you mentioned, and so certainly that could have an impact for our region. It really does do depend. I know with some local research that we do have here, the strength of the ENZO cycle certainly has an impact as well. So while we may have a weak La Nina and that may cause above normal lake effect snows on average, a strong La Nina might not be quite as bullish or robust as far as those snows go. So it really is a mix of things. During an El Nino year, sometimes the southern jet stream becomes quite active. And if you get the right phasing of the jet stream, you can certainly end up with some pretty strong storms that move up into the Great Lakes region, but that being said, it really is a mix. You can have that in really any sort of broader atmospheric or oceanic phenomenon like ENZO.
DN: What are we anticipating the beginning of this, maybe it's most impactful point, and when we expect to kind of move out of the conditions as they're approaching?
JD: I mean, we are expecting some pretty cold weather for the -- really the foreseeable future, certainly through the end of January and perhaps into the first half of February, just looking at some of the extended range here. And you'll have a little bit of a “warm up” in between where you may hit sort of the near 20 or the upper teens, but we're expecting a pretty prolonged period here of some cold conditions.
DN: Well, we'll all be bundled up and listening in for the information coming from you folks. I appreciate giving us kind of the primer on what a polar vortex is. Joe, thanks very much for taking the time to talk with us. We appreciate that today.
JD: Yep, no problem.
KW: That was Joe DeLizio with the Gaylord office of the National Weather Service. He spoke with WCMU's David Nicholas.
