Mailbag: What is the polar vortex, and when the heck will it feel like winter?
Hello friends! We’re back and happy to jump right back in with another weather mailbag post. We’ve been hard at work collecting questions and gathering answers. Let’s dive right in, shall we?
Is there a winter-centric complement to the Atlantic hurricane season? something like the “Arctic polar vortex season”? (@vegitalist)
This is such a cool question. The short answer is no, at least not as it directly relates back to the polar vortex. The polar vortex exists year round. Think of it this way – the polar vortex gets smaller and retreats closer to its home near the North Pole during the summer. During the winter season, the polar vortex grows in strength and size. When its at its strongest, it dominates the pattern and much of the cold air can stay bottled up near the poles and the Arctic. When it gets weaker and disrupted, pieces of it can often swing southward closer to us. When the polar vortex pays us a visit, its actually just a piece of a larger vortex that exists year round.
When it comes to seasonality, there is definitely a propensity for stronger mid-latitude cyclones during the winter months. We live in the middle latitudes of the Earth, and during the summer the jet stream retreats to our north. In winter, it swings back down towards us. The strong jet dynamics can lead to the development of stronger cyclones in our area during the winter months.
For more on the polar vortex, you can visit our article from a few years ago where we broke it down in some further technical detail!
I feel like we used to have a solid fall season in NYC,but over the years, possibly due to climate change, it’s been encroached upon by longer summers and winters. Is this true or am I making this up? (@chillbutvibrant)
We spent some time trying to figure out the best way to visualize this and ultimately settled on a simple temperature trend during the months of Fall in Central Park. Taking pure, raw data the temperature on average has increased 2 degrees or more in Central Park since weather data collection began. That is certainly not a nominal trend – it’s fairly significant. I think it’s fair to say that the Fall season has gotten warmer in general.
Length of the season is a bit more difficult to plot, but we’re working on a few ideas. We’re trying to figure out a temperature or dew point threshold that could be used as a good dividing line between Summer and Fall. We will revisit this in our next mailbag with a more in-depth response as to whether or not Fall has gotten shorter.
Can you have a 10/10 day in the winter? (@etu001)
We’ve been receiving quite a bit of feedback regarding our weather rating system over the past few weeks, so we figured answering this one in a straightforward manner was the best approach. The short answer is yes! But it’s important to note that the rating scale is based on how comfortable the weather is. An ideal 10/10 weather day has temperatures of 60-75 F with low dew points and zero precipitation. It would be more difficult to get this type of day in the winter, but it’s not impossible.
When will real winter weather begin? (Email)
The burning question on everyone’s mind. It has been a very warm two weeks with record warm temperatures in NYC last week and more warmth expected during the week ahead. The weather pattern is undergoing some changes, though, mainly in the Arctic regions. High latitude blocking, or ridges of high pressure that develop in the Arctic regions, is forecast to become quite notable by Christmas. This will act to disrupt and dislodge cold air and move it southward into Canada and eventually the United States.
Our hunch is that the weather pattern will turn colder in early January. It’s far from a sure thing when it comes to snow, but there does appear to be growing support for colder than normal temperatures during that time. It will be a welcomed change from the apocalyptic-like warmth of the weeks past.
