Back for more?! Thanks for checking in for another edition of….Will this winter be bad? The past two winters have been anything but winter in New England with limited snow and cold.
Note that the past TWO winters have landed on that list! For a snow lover like me….ridiculous! The lack of cold is even more telling. This chart here shows the past two winters and the number of cold days (below normal) versus the number of warm days (above normal).
Incredible. Over the past two winters, there were only 22 days (out of a possible 181 days) that were deemed cold. Some of this is climate change doing its thing, meaning, it either dampens a cold pattern or amplifies a warm pattern, so having a winter where the cold days outnumber the warm days by a large margin is rarity these days.
I think for our upcoming winter, we will likely see a few more cold days and more snow than these past two winters , but a mild winter with below normal snow appears likely.
That’s the TL:DR summary…..Read on to get yer nerd on!
ENSO
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, a phenomenon known as the El Niño-Southern Oscillation (ENSO). During the cool phase of the oscillation, cool water exists along the equatorial pacific, while warm water exists in the same region during the warm phase. Last year the ENSO state was in a rather strong El Niño state, but this fall and upcoming winter we are most likely returning to a La Niña state. Check out the latest sea surface temperature anomalies:
That cool patch of water along the equatorial Pacific is the dead giveaway to a La Niña state. For many La Niñas, the global patterns look like this:
Here is a closer look to what a typical La Niña winter looks like across North America:
Now in terms of winter snow during a La Niña winter, this is typically what happens:
Notice a swath of above normal snow (blue shading) across the northern tier of states (including interior New England) yet farther south the brown-tan shading indicating a dearth of snow extends up into eastern New England.
Recall that like El Niño, La Niña varies in intensity and this La Niña looks to be weak at best so you might be wondering if a weak La Niña leaves a different seasonal snowfall footprint? The answer is yes! Check it out:
You still see the same general theme with above average snow across the northern tier of states BUT there are two areas of deep blue in the upper Midwest and much of southern-central New England, indicating way above normal snow.
Computer Models
The computer modeling for the upcoming winter is loaded with mild air. First up, the European Centre for Medium-Range Weather Forecasts (ECMWF) seasonal model:
Eesh….a lot of yellow-orange colors across the United States…..which implies above normal temps. Second opinion? Sure! Below is the North American Multi-Model Ensemble (NMME), a collection of seasonal models that shows the probability of above normal temps:
This map is a little different than the ECMWF temperature map, as it shows the probability (likelihood) of seeing above normal temps. For New England, that will most likely look like a 60-70% chance of seeing above normal temps for the winter.
Keep in mind that even with these two different models advertising the likelihood of mild/warm temps this winter it does not mean there will be no cold air, rather, the mild days will outnumber the cold days. In terms of snowfall, if you have limited cold, you’re less likely to have a lot of snow.
Fall Drought
To say it’s been dry would be a vast understatement. We have fallen into a fairly significant drought this fall as many cities and towns have picked up less than 30% of their normal fall rainfall (hence all the brush fires recently)
As of this publication (November 20th), we are on pace for the driest fall on record. Our driest falls typically portend to a low amount of snow. Check out the driest falls on record for Boston and Worcester:
The above list also shows winter snow totals following those dry falls. For Worcester, every one of those dry falls listed went out to produce only half the total snow in a typical winter. For Boston, four of the five dry falls were followed by limited winter snow. Snow lovers, you can hang your hat on that 2013 example. That was a winter with no La Niña or El Niño (ENSO neutral), more on that later.;o)
Snow Drought—Revisited
In last year’s winter outlook, I pointed out that while Boston’s seasonal snow average is 49”, most winters produce between 40-49” of snow (less than average). The reason being is that those big snowy winters, like 2014-2015 with 111”, will increase average snow totals. Now in terms of a snow drought we appear to be in, yes, I still believe that is the case and a refresher over the past nine years shows only two winters with above normal snowfall!
But look at the winters from 2004/2005 until 2014-2015…there are some meteorological bangers in there!
Now, lemme take you waaaay back to the winters of Jeremy Reiner’s childhood in the 80s!:
look at all those snowless winters! The point here is that snowy winters ebb and flow here in New England, the question is, when does our snow drought end? This year? It’s possible but not probable.
Winter Predictions
With all of this in mind, I think we’ll finish this winter with below normal snow for much of the region but more than we have seen in the past two winters.
Fear not if you ski, I think snow totals should be pretty close to normal up north across northern New York and New England:
What Could Go Wrong?
The short answer is…a lot. For starters, instead of ENSO being in a weak La Niña state, ENSO could end up being “neutral”. When in the “neutral” position, other components of the atmosphere can more readily exert their influence on our weather patterns:
This cute little cartoon shows what I am talking about. You see two acronyms on the gentlemen in that picture, AO and MJO. Without getting too deep into the weeds, the MJO stands for Madden Julian Oscillation which is a tropical wave that moves eastward completing its cycle every 30-60 days.
The MJO affects precipitation, atmospheric circulation as well as temperature. The AO is short for Arctic Oscillation, and there are two phases: a positive and negative:
Basically, a positive AO reduces the odds of a cold and snowy pattern for New England, whereas a negative AO usually increases the odds of cold/snow for New England.
So with a neutral ENSO condition and the right combination of the other parameters in the atmosphere in place, New England could end up with at or above normal snowfall this winter (like that 2013-2014 snowy winter referenced earlier in the blog). Just some food for thought.
All in all, I’m predicting a little more winter than we have seen over the past two years and while this snow lover is hoping for a very snowy winter like those we’ve seen in the past, it’s probably unlikely to happen.
~JR