It’s looking like this winter will be a stormy one
Here's David Epstein's 2018-2019 winter weather outlook for New England.
It’s time to start thinking about what this winter could be like.
Every year, you’ll find all sorts of prognostication on whether New England’s winter will be filled with storminess, snow, prolonged cold, mild spells, or not much in the way of precipitation. Depending on what you want to happen, you can probably find someone who is predicting it.
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There is no shortage of long-range forecasts for this winter, and now you can add me to that list, too.
Here’s what historical data tells us about winter in New England, what forecasters have to consider, and what I’m thinking about the upcoming winter.
What history tells us:
On the most extreme ends of the spectrum, New England has winters when it rarely snows, perhaps less than 20 inches, and then we have winters when we get a lot of snow — over 80 inches. There are winters when we don’t see any prolonged cold and other winters when the cold can last for three, four, or even five weeks at a time.
The 30-year average snowfall in Boston is about 40 inches.
Snowfall is heaviest in western and northern New England on average.
In most years, January and February are the snowiest months, and January is also the coldest. Averages are virtually meaningless, though; in any given year, December through March and even April could be the month that winds up with the most snow.
Monthly climate normals for Boston.
What forecasters consider:
Usually there are all sorts of winter weather predictions before the season even begins. This year, forecasters at BAM Weather are predicting a colder than average winter for the eastern part of the country; WeatherBell is predicting a very severe winter in the East but that northern New England won’t be much colder than average; and NOAA isn’t forecasting a blockbuster cold season.
Forecasters have to consider a range of factors that will affect the upcoming winter weather, which is why there’s rarely across-the-board alignment on long-range forecasts.
One of the more important and better known variables we’re looking at is the El Niño Southern Oscillation (ENSO), which indicates whether temperatures in the Pacific Ocean, west of Peru, are warmer than average, colder than average, or simply average for the season.
Right now, forecasters are noticing a pool of warmer-than-average water in the middle of the Pacific, but not along the coastline. It’s a configuration called a “Modoki El Niño,” and if it lasts for a couple more months, it’ll become official.
Modoki El Niño years tend to put pressure on a colder-than-average East Coast winter; it’s the reason why many forecasts are predicting an average to above average snow season on the East Coast.
Water temperatures in the central Pacific are warmer than average. (NOAA)
ENSO aside, some of the other factors that go into a long-range forecast include the following:
- The ocean temperature configuration, which, depending on where areas of warm and cold water are located, directly influences our weather patterns.
- The placements of high and low pressure around the globe and their strength; for example, a trough of persistent low pressure in the East may bring us a stormy winter, but a ridge of high pressure in the East can mean mild conditions.
- The thunderstorm cluster across the Pacific Ocean, which plays a major role in how the Jet Stream controls the flow of storms and air masses in the mid-latitudes around the globe.
- Add in sunspot cycles, which are currently at a low point. Some research shows these favor colder winters in our region.
There are eight phases to clusters of thunderstorms in the Pacific Ocean. The placement of these storms throughout the winter season has a dramatic impact on the weather across the United States.
All of these things considered, you can see why it becomes very difficult to predict who’s going to see the most snow and where and when a midwinter thaw might occur. January and February are still a few months away, too. Lots of things that affect the forecast can, and certainly will, change by then.
What I’m predicting:
Meteorological winter begins December 1 and ends at the end of February, but the snow season lasts for another 30 to sometimes 45 days beyond meteorological winter. As we all remember, when March hits, there can be some big storms.
Most of the forecasts I’ve seen keep temperatures across much of the East average or cooler than average. This would tend to lead to a winter with typical snowfall or above average snowfall, which seems reasonable to me.
There are no guarantees in the forecasting business, but there are a couple of things I think are a shoo-in for this winter.
First, February 2019 will be significantly colder than February 2018. This year’s setup is different than last year because pools of warm and cold ocean water aren’t in the same positions as 2017. Last year was the warmest February on record, and it’s highly unlikely we’ll be anywhere near that.
Second, this looks to be an active winter in terms of storminess. I think there’s going to be a lot of action across the country. The challenge will be figuring out the exact track of those storms, which will determine whether New England is on the rainy side, the snowy side, or if they miss us entirely.
And finally, if El Niño kicks in stronger over the next four weeks, it could mean a later start to full-on winter weather, with December seeing milder air and less snow.
Over the next month, forecasters will be closely monitoring the temperatures in the Pacific to see how, exactly, the El Niño is evolving. A more widespread, powerful El Niño could mean less snow and more warmth for New England, but a less common Modoki El Niño could bring lots of opportunities for shoveling this winter. Stay tuned.
