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What factors are contributing to Central Pennsylvania’s mild winter?

  • Scott LaMar

Airdate: February 16, 2023

Most of the buzz in the region this week has been about the unusually warm weather in central Pennsylvania.

Temperatures in the 60s Wednesday and Thursday spawned even more people to wear shorts and a lot of car windows down. Sixties in February aren’t normal but this winter has been unusual anyway.

Other than just a few days here and there, temperatures have been above normal most days this winter and there’s been very little snow.

So, what’s going on? What are the factors that have led to this mild winter and will it continue?

On The Spark Thursday was ABC27 meteorologist Dan Tomaso, who explained why the winter has been so mild,”We are in a third consecutive year of La Nina conditions over the Pacific Ocean now, where I’m talking about the Pacific Ocean is near the equator and west of South America. And I think that’s really hard for people to understand that an area of the ocean that’s thousands of miles away could have such a large impact. But it really does drive how the weather can behave across Mexico, the Caribbean and North America. The reason being is when La Nina is present, there’s cooler waters over the eastern equatorial Pacific, and that really slows down our southern jet stream. So we talk about the jet stream a lot on television. We talk about it in terms of bringing weather to our region. But the jet stream itself is often split into three. You have a subtropical jet stream. You have basically a high metal jet stream and an arctic jet stream of air. And the subtropical jet stream is the one that may be responsible for some pretty large storms, whether it’s winter storms like nor’easters or coastal storms. And when we don’t really see a large connection with that, unfortunately, in years when we have La Nina, there’s not a lot of storms coming from that direction and that really grinds to a halt. The number of snowstorms we can get from the south and our big ones generally come from the south. Our smaller storms come from the west and northwest, straight out of the Arctic. But if you can imagine, you know, the warm Gulf waters, there’s a lot of moisture there off the Gulf Coast. And when we pick up that moisture and it heads north with an area of low pressure, that’s when we get some pretty big snowstorms. Now, the other part of this argument should be a fairly simple one for everyone to understand. We simply have not had the cold air available either.”

Tomaso was asked whether climate change is a factor in this winter’s weather,”climate change is 100% always in the background of everything going on. And I remind our team this all the time that unfortunately we try to look at the past to try to help predict the future. So we look at past weather patterns that could be similar to this one to help predict maybe on a seasonal scale like we’re looking ahead to spring or summer. The problem is we’re kind of in a territory now where it’s hard to find similar years with similar warming. And what I mean by that is if the planet is constantly warming in the background, those conditions weren’t present 30 or 40 years ago. So even if climate change is changing the background temperature, one or two degrees, that does have a pretty profound impact on the overall global weather pattern. Doesn’t seem like it would. But again, when you’re trying to compare to the past to predict the future, we’re already seeing that it’s been really hard to find similar conditions before to help predict the next season or the next year.”

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