Welcome back to another installment of “how much snow am I getting this winter?” because let’s face it, that’s all anyone who reads a Winter Outlook is really interested in, amiright? Well, let’s not waste any time…let us do this!
Before we move forward, let’s take a quick recap of last….winter?? I mean, yes, we technically had winter, but it was like living on easy street (or Nightmare On Elm Street depending on your point of view) with the incredible lack of snow and warm temps.
It was 4th Least Snowiest winter and the 5th warmest winter for Boston. Can that happen all over again? Doubtful, as I think we’ll see more snow than last winter and have a little more cold air to experience than last winter as well.
In a nutshell, here is what I am expecting:
Let’s look into the players for the upcoming winter.
For starters, I like to look at the state of Equatorial Pacific Ocean temperatures and more directly, their anomalies (warmer or colder than normal) as the Pacific Ocean, the largest ocean in the world, has a huge impact on global weather patterns. Recall, the anomalies oscillate up and down between warm and cool and this oscillation is more formally known as the El Niño-Southern Oscillation (ENSO). During the cool phase of the oscillation, cool water exists along the equatorial pacific, and in the warm phase, warm water exists in the same region. The past three years the ENSO state has been in the cool phase, more commonly referred to as La Niña. Well, La Niña is gone and has been replaced by El Niño.
LOL…a classic SNL skit. I digress….When checking out the latest Sea Surface Temperature Anomalies, you can see the warm water along the equatorial pacific at this time:
Compare/contrast that to a year ago at this time and look at the cool water in nearly the same location!
OK, so we have an El Niño now, but will that carry us through winter? The answer is yes and it’s likely a strong El Niño when checking out some of the seasonal model predictions:
Model consensus predicts this El Niño as moderately strong…certainly our strongest since 2015-2016. In terms of what El Niño means to the Nation as a whole, this is the typical El Niño winter across the United Sates:
An El Niño usually means limited arctic air into the United States, dry conditions across the Northern Plains into northern New England (ski country), and wet conditions along the Mexican-US border through the Gulf States as well as Florida (pack your rain gear for any winter trips to FL).
But not all El Niño’s are created equal and a weak El Niño leaves a different footprint on southern New England snowfall than a strong El Niño. Check out this graphic! (Created by Josh Timlin, https://twitter.com/joshtimlin ; Science teacher/Weather enthusiast. Thanks Josh!!)
It looks at all the El Niño’s and La Niña’s in Boston (as well as ENSO neutral conditions) and the corresponding snowfall for a particular winter. The takeaways from that graphic are:
Strong El Niño’s don’t usually produce big snowy winters for Boston (same can actually be said about strong La Niña’s!), and Boston’s snowiest winters usually occur when ENSO is in a weak El Niño.
OK, so based on a moderately strong El Niño, snowfall likely below normal for Boston (normal being 49”).
When putting together a Winter Outlook I try to find similarities between the upcoming winter versus previous winters, and for this winter I wanted to find El Niño winters that followed 3 La Niña winters- a rarity! What I found were the three following winters: 2002-2003, 1986-1987, and 1957-1958.
Yowza…Those three winters produced average/above average snowfall with February 2003 producing a whopping 41″ of snow! Using just three analogs is probably not a strong enough signal to latch onto. The other thing about analog forecasting is that the Earth is warmer, especially the oceans, than 30-60 years ago, so the response from our warmer oceans onto the atmosphere may not be the same as 30-60 years ago. Food for thought.
The computer models we use for seasonal forecasting are a bit different than the models we use for daily forecasting, but they can still be very helpful in putting together a Winter Outlook. When starting the ECMWF seasonal model, the model does see an El Niño in play for the upcoming winter and its subsequent effects on global atmospheric patterns (i.e., limited arctic air for the United States and enhanced precipitation across the southern states as well as up the Eastern Seaboard).
What is of interest is the 500mb level (also known as the jet stream level).
Lotta yellow. ;o)…..in particular, across much of Canada. That is not a temperature forecast but rather an indication of what we call Blocking, High Latitude Blocking in particular. When High Latitude Blocking is present, it can force the jet stream and cold air farther south. IF Blocking were to occur, it would set up a storm track across/just south of New England and provided the air is cold enough (a challenge in an El Niño winter), produce snowstorms. Interesting to note is that we had a fair amount of High Latitude Blocking this summer across Canada. That led to an unusual number of wildfires across Canada (and subsequent smoke here in New England) and helped to contribute to our rainy summer pattern.
That’s just one model though…what are the other models saying about Blocking? Solid Question!
There are certainly some similarities, and it would be very rare to have all three models look exactly the same, but overall, there does seem to be at least a hint of High Latitude Blocking at times during winter. If/when the blocking occurs, it would tip the scales in favor of a stormy pattern for New England. The wildcard, as previously noted, would there be enough cold air in place for the storms? Tough to know here in November what a storm may or may not look like in February.
“We didn’t get any snow last year; we are totally getting crushed with snow this winter!!”-New England Snow Lover
I hear that most often from the snow lovers during/after a winter like last year (only 12” of snow) and in reality….that’s not how it works. When you look at Boston’s average seasonal snowfall it’s around 49” but…when you look at the distribution of seasonal snowfall for Boston, more winters fall short of that number versus exceed that number. Check out Boston’s seasonal snowfall distribution:
Based on these data, Boston will average between 40-49” of snow in the winter months. Now, if you look back through Boston’s snowfall history you will see stretches of snowy winters and snowless winters. There are two such stretches: we just came out of a snowy stretch a few years ago, from 2004-2005 to 2014-2015. Check out this 11-year stretch:
Seven out of eleven of those winters had above normal snow fall with three of those winters placing in top-10 snowiest winters!! Yowza. Now check out this 10-year stretch from 1982-83 to 1991-92:
A brutal stretch for the snow lovers. I bring this up because we may be in such a stretch now. It’s hard to know for sure if you’ve hit a snow drought until you are well into it, but it certainly feels like it could be the case. The last five winters have been meager at best, certainly three of the last five have been way below normal.
So, with all this information here is what I am thinking for snowfall this winter:
Some notes on the snowfall:
- Overall, below normal compared to normal.
- El Niño winters tend to produce more snow in mid-late winter (including March) versus early winter.
- Even with below normal amounts, we are most likely receiving more snow this winter versus last winter.
Welp, that’s what I have for ya….we shall see. Seasonal forecasting is difficult at best….so let’s all #EmbraceWinter and see how this thing ages!