How much total snow is Massachusetts forecast to get this winter? The WBZ NEXT Weather team shares their prediction and a look at how this forecast compares to past winters.
BOSTON - Last year, we started out our winter outlook by saying it couldn't possibly be more lame than the previous winter. Welp.
While the 2022-23 season produced 12.4 inches of snow, 2023-24 followed it up with a truly pathetic 9.8" of snow, the third least snowy ever recorded in Boston.
It's been 1,000 days since Boston had a 4" snowfall, the longest stretch on record. I am still working off the same bucket of salt I bought in November of 2022.
It's safe to say there's never been a weaker set of back-to-back winters. They weren't just snowless but extremely mild (the fifth and seventh warmest on record). The outlook for a milder and less snowy than average winter certainly verified.
So, we can't do that again, can we?
Let's look at where the atmospheric variables stand heading into this winter, and what they may mean for the months ahead!
We usually start out talking about the state of ENSO, the El Nino Southern Oscillation. Last year we had a strong El Nino event which is just about guaranteed to produce a weak winter in Massachusetts. El Nino overpowered everything and panned out about as expected. This year there's a significant shift to La Nina conditions, meaning warmer than average water in the equatorial Pacific has switched to cooler than average.
The expectation is that this La Nina event will remain pretty weak, and I don't feel it will have an outsized influence over the winter pattern. That said, it is coupled with a negative Pacific Decadal Oscillation, or -PDO. This features warmer water over the northwest Pacific and cooler water near the west coast of North America. In fact, the last two months have been the most strongly negative on record.
A significant portion of our quieter winters feature a -PDO and La Nina combo. I tend to feel the PDO region is an even bigger indicator of where our winters will head than ENSO, and since it's a decadal oscillation we can get locked into similar winters for a while. It may be a big reason we've been on a pretty benign stretch for years now.
Top of mind for many in Massachusetts is the extremely dry fall we've had. It's been the driest on record, though some towns may fall a couple spots in the rankings before the end of November. Common sense may lead you to think that since it's been so dry, that's likely going to change in winter to balance out. But historical data says that has not been the case.
The five driest autumns on record have been very low in the snow department, with an average of 21" for the whole season in Boston. All of them had under 30". Nine out of the twelve driest had below average snow, and the few that did produce more than average had cold Novembers leading into the season.
Speaking of November, it often points into the direction of the winter pattern. Cold Novembers frequently turn into snowier winters, while mild ones do not. Every single one of the Top 10 warmest Novembers on record had below average snowfall in Boston. This one probably won't finish inside the Top 10, but it will certainly go into the books as warmer than average (Sixth warmest on record through the 20th).
Something some seasonal forecasters keep an eye on during the autumn is the runup of snow cover in Siberia. It's thought that a fast onset helps load a pattern that can weaken the polar vortex, allowing more cold to spill into the U.S. and Europe (with the opposite being true as well). This October ended with the smallest snow cover reading in the past decade, which is not a bullish sign for cold here.
As for the polar vortex, it's going to be starting the season in near record-strong fashion. Strong may sound scary, but that's actually what keeps arctic air more bottled up near the pole.
Now even with a strong polar vortex, it can "stretch" and allow intrusions of cold air. We may see one of these right at the end of November and start of December, giving us a shot of winter weather. After that I expect it to retreat to a milder December pattern.
The million-dollar question is whether the polar vortex truly pairs to the stratosphere where our weather happens. A couple years ago we had a strong polar vortex, but it never really "spoke" to our part of the atmosphere. The result being that we still got some cold shots and a couple storms.
As for seasonal computer guidance, there's not a whole lot to say here except that multiple models are all in agreement of a mild winter locally. They're certainly not gospel, but something to consider.
Putting it all together, it's looking like another fairly tame winter here in the Boston area.
I don't expect it to be as quiet as the last two winters, but we are calling for less than 30 inches of snow for the season in total. That's more than the 9.8 inches that fell in Boston in 2023-2024, but below the overall snow total average for a Boston winter, which is 49.2 inches.
I also expect more cold shots than we had during the last two winters, even if, overall, the winter ends up warmer than average over the three-month period. La Nina winters can be quite variable with significant cold shots and significant warm-ups as well. Look for periods of Pacific ridging allowing for dumps of cold air to be deposited into the lower 48 states at times, with the main focus being on the western and central U.S. but some of them spilling our way too.
The combination of cold air being available to our west and some ridging across the southeastern U.S. should yield more active weather than we've had this fall, and that overrunning setup should also produce a pretty snowy winter across the northern New England mountains where there's more access to that cold. Good for ski season!
And as always this is just us trying to read the tea leaves. Nature always has the final word, so we'll see what it dishes out!