Does a cold November mean more snow for Boston this winter?
BOSTON - We're on to December. But before we get there, I think it is worth taking a deeper dive into November 2023. There's an old saying/rule amongst meteorologists that goes something like. . . "as November goes, so goes the winter." Meaning, the weather conditions in November can often be a hint as to what the upcoming winter may be like.
And, because I know that just about all of you would LOVE to know what we are in for this winter, let's get nerdy for a few minutes!
Putting it simply, November 2023 was dry and chilly, at least compared to averages.
The month is going to finish about 1.7" below the normal precipitation. We really only had one or two days with meaningful rainfall.
Perhaps even more interesting, November 2023 will finish with temperatures just shy of 2 degrees below normal.
Anytime we get a below average temperature month these days it seems worth noting. Interestingly enough, over the last 10 years, exactly half of the Novembers have would up below average. That is more than any other month, tied with April. Most months, as you might imagine in this warmer climate, tend to finish above average more often than not with September and December chief among them.
If you go back a bit further since the year 2000, 14 of the 23 Novembers have been below average!
Does a cold November lead to a cold or snowy winter?
I am glad you asked! For the purposes of this blog, we will look back to all the Novembers and the following winters since the year 2000.
Not including this year, there have been 13 below average Novembers in this span. Ten of the 13 winters that followed had ABOVE average snowfall! I would say that is a pretty significant correlation!
However, there is a flip side to that coin: In the last five years, we had two very cold Novembers, not all that different from this year. In 2019, November temperatures averaged 2.2 degrees below average and in 2018, 2.1 below average and BOTH those winters had very little snowfall. So, perhaps something has changed in just the last few years? Does the "November Rule" no longer hold? Possible Conclusion: Expect above average snow this winter.
Let's keep digging. . .
If we look at winter temperatures (Dec-Feb) following cold Novembers, we get a very similar story. Again, since 2000 there have been 13 colder than average Novembers (not including this year). Nine of the following winters (Dec-Feb) finished with below average temperatures. Another very interesting correlation!
But again, 2018 and 2019 were outliers. In fact, despite a very cold November in 2019, the winter that followed was extremely mild, nearly 5 degrees above the average. Possible Conclusion: Expect below average temperatures this winter.
What about snow in November? Boston did not have any measurable snowfall this November. This is nothing new. Since 2000, the city has only measured snow in five of 23 Novembers.
When we have a snowless November that leads to about a 66% chance (two in three) of a below average snowfall that winter (Again since 2000). In those five years when we measured snow in November, four of the five (80%) had above average snowfall in the winter that followed. Another pretty good correlation! Possible Conclusion: Expect below average snow this winter.
Lastly, it has been quite dry in the last few months...might that portend something for the months ahead?
Looking at dry Novembers alone, there have been 15 Novembers with below average precipitation since 2000. Seven of the 15 led to below average snow. . . nothing to see here.
If we take the dry October and Novembers together (Boston will finish more than 4" below average this Oct/Nov) there is a bigger correlation here: There have been eight years since 2000 with October-November stretches that finished 2" or more below average. Six of the eight years had ABOVE average snowfall that winter! Possible Conclusion: Expect above average snow this winter.
If you are still reading this, I will give you props. . . this is a lot of data!
What's the winter weather forecast for New England?
Given the November we just had, the quick takeaway would be that odds seem to favor a cold and snowy winter ahead.
But, 2018 and 2019 give me pause and reason to question the data. How much does climate change and our warming oceans play a part in all of this? Are we seeing the ramifications of that now? Not to mention, there are several other atmospheric conditions (including a strong El Nino) going on this winter that seem to point toward a milder than average winter.
For now, I will stick by our WBZ winter forecast that we made a few weeks ago. Despite the cold November, we are forecasting a milder than average and slightly less snowy than average winter.
Seasonal weather forecasting is very challenging. Native New Englanders certainly know that our weather can change on a dime, and we need to be prepared for anything.
This weekend seems like as good a time as any to gas up the snowblowers and to ready ourselves for whatever Mother Nature has in store for us. The one thing I know for sure, our team is ready to go!
Stick with WBZ-TV, WBZ.com and CBS News Boston all winter long, we got your back!