Something historic is brewing in the Pacific Ocean. Scientists are predicting the strongest El Niño on record over this fall and winter, carrying more heat and moisture across the globe.
While that may seem far away, these natural forces will shape our winter weather here in the North Country.
Catherine Wheeler spoke with Samantha Borisoff, a climatologist with the Northeast Regional Climate Center at Cornell University, about what to expect.
Their conversation has been edited for length and clarity.
Borisoff: El Niño is a warming of the ocean waters along a certain section of the Pacific Ocean near the equator. Along with that, it is an atmospheric response that's coordinated with that warming. So, it's kind of two pieces. You need the warming of the ocean waters in this area of the Pacific Ocean, but you also need this atmospheric response, which is a shift in global weather patterns. You need that combination for several months together. It's like a three-month period over five overlapping consecutive three-month periods to actually be considered an El Niño.
Wheeler: It's brewing in the Pacific, which seems so far away from us, but it really does have a global impact on our weather, right?
Borisoff: Yes, absolutely. In general, we expect these specific patterns to emerge. It's not a lock-in, right? Every El Niño is different. Every year is different, and there are other factors that influence these weather patterns. But, in general, with an El Niño during winter, we would expect the active storm track to be across the Southern U.S., and that tends to go up the East Coast, as well. That tends to mean that the East Coast gets an increased number of nor'easters. So, we have that part of it. Then, the northern half of the U.S., not all parts, but some parts, tend to be warmer than normal. Then, the Ohio Valley tends to be drier than normal. Again, that's what we expect; that's not always the case. But, when we get strong events like we're expecting this year, we tend to see that pattern emerge more frequently.
Wheeler: What does that look like though Northern New York? We're a little bit further back from the coast.
Borisoff: For Northern New York, one of the things that we see during most El Niño events, is, generally, below-normal snowfall related to lake effect because the active storm track is across the Southern U.S. and up the East Coast. In general, the cooler air tends to be a little bit more locked up to the north, and we get fewer cold air outbreaks. We don't get the setup for lake effect that we would typically need. In general, it's a reduced amount of lake effect snow, but there are always caveats, right? So, that's what we would expect. But if it is warmer, those lakes can stay open and warmer longer, so you get one blast of cold air or a prolonged cold period, then you could still get the lake effect. So, it's not saying, "Oh no, no, we're not getting it." It's just, in general, we tend to see reduced lake effect if we get the right conditions.
Wheeler: I had read that in a previous stronger El Niño year. There was a reduced amount of lake effect snow around Buffalo, Syracuse, Watertown and those areas that really get hit pretty hard, right?
Borisoff: Yes, so the least snowy winter on record since 1950 for Buffalo, Syracuse, and Watertown is 1982-83 during one of the strongest El Niños on record.
Wheeler: What does that look like for temperature around Northern New York?
Borisoff: Temperature is a little bit more tricky, a little bit more nuanced. During El Niño events, parts of the northern tier of the U.S. can be warmer. We do see more generally that colder air tends to be locked up, but even with that said, we can still get cold air outbreaks. This is just a generalized pattern. Each day, each week, each month within the winter season can look a little bit different. We tend to see that cooler air tends to stay locked up a little bit more frequently, but then we also have to factor in the fact that, in general, winters are warming across the U.S., right? That also has an influence. So there are many factors that go into what a winter could be like.
Wheeler: El Niño is a natural process, but how is it impacted by human-caused climate change?
Borisoff: We know that ocean temperatures are warming, right? And, El Niño is a warming of the equatorial Pacific Ocean. So, there's an interplay there. We also know that our climate is warming, as well, right? So, with the warmer climate, we have warmer temperatures, which keep lakes open more during the winter, things like that, but also warmer air can contain more moisture. So, sometimes when we get these nor'easters, we get a sweet spot where we get a little bit more moisture infused into that just because there's the sweet spot in temperature where you can get this heavy snow, but also we have more fuel in warmer ocean water. So, there are these kind of factors that kind of come into play.