El Niño returns: What's in store for Worcester and New England this winter?

A woman shovels snow from her walkway on Tatman Street in a file photo.
A woman shovels snow from her walkway on Tatman Street in a file photo.

WORCESTER – Are we going to get frigid temperatures and a lot of snow this winter?

It’s a question we New Englanders ask this time of year when the thermostat starts to drop and we see a few snowflakes in the air, a sign that more of the white stuff could be on the way.

To get an answer, there’s a wrinkle that must be considered this year when it comes to prognostications. It’s El Niño, as the naturally occurring phenomenon is back in the Pacific after the last one in 2018.

Scientists explain El Niño creates warmer ocean surface temperatures in the central and eastern Pacific near the equator. The warming impacts the jet stream and generally results in colder and wetter weather in the southern U.S., and warmer and drier conditions in the northern half of the country.

But’s it’s more complicated than that, and to get a handle on what it all means for Worcester, the Telegram and Gazette spoke with several climate experts. Here are their takes, including the chances of the quintessential New England snowstorm, the nor’easter, bearing down on us in the months ahead.

'Not the hugest of impact'

Here's how Lauren Casey, a meteorologist at Climate Central, sees El Niño’s local impact: “(Worcester) will not have the hugest impact from El Niño, in contrast to other parts of the country.”

Two jet streams are in play, the Polar and the Pacific. Casey said El Niño pulls the Pacific jet stream further east, and any effects in Worcester will likely be minimal. It could mean cooler, wetter and stormier weather in the southern U.S.

But pay attention to the Polar jet stream. It hovers above Canada, and El Niño could cause it to dip our way, bringing an occasional arctic blast of air.

Climate change in the mix

New England winters are warming, so a warmer/drier stretch from El Niño shouldn't disrupt us too much. In fact, average temperatures over the past 53 years (1970-2023) in New England climbed at least 5 degrees Fahrenheit during the “meteorological winter” from Dec. 1 through March 1, according to Climate Central.

The five-degree swing is the biggest increase of any sector in the U.S. over the past half century during the meteorological winter, according to Climate Central's winter warming analysis. The finding is based on Climate Central’s review of data from the National Oceanic and Atmospheric Administration and NASA.

Climate Central's national winter warming map includes Boston and Springfield. Both cities experienced rising average temperatures over the past 53 years: 3.4 degrees Fahrenheit in Boston and 4.9 degrees Fahrenheit in Springfield. Nationally, winters warmed by 3.8 degrees Fahrenheit on average across 233 U.S. locations.

In the Worcester area, the meteorological winter's mean average temperature from 1970 to 2023 for December, January and February is 29.8, 24.3 and 26.7, respectively, according to the National Weather Service. NOAA has a 40% to 50% confidence level that this year's meteorological winter in Worcester will have average temperatures above normal.

So, what’s causing New England winters to warm up over the past 50-plus years? “Climate change,” said Casey. “There’s extra carbon in the atmosphere.”

Drier conditions can mean more storms

Drier air in the Northern U.S. from El Niño can create a paradox, said Richard Rood, professor emeritus of climate and space sciences and engineering at the University of Michigan.

“There might be more snow if snowstorms do occur,” said Rood. He explained that drier air normally causes shifts in storm tracks, pushing them to the coast or out into the ocean. Since ocean surface temperatures are rising due to climate change, Rood said the warm water feeds storm tracks with moisture, creating more intense storms.

“If you see a storm like that, you’ll likely see a lot of snow,” said Rood.

Is this year's El Niño more powerful than 2015-2016?

The last El Niño that scientists recognized as packing a powerful punch was in 2015-2016, and this year's version doesn't appear to have the same strength. In 2015-2016, the Worcester area had 47.2 inches of snow, including 20.6 inches in February, according to the National Weather Service.

Johnna Infante, a meteorologist in NOAA’s Climate Prediction Center, has the data to support that comparison. This year’s El Niño increased surface temperatures in the Pacific Ocean 1.8 degrees Celsius above normal levels from September through November. That is less than the 2.4 degrees Celsius in the 2015 El Niño over the same three-month period.

“So it’s getting there, but not quite at the level of 2015,” said Infante, who is a New England native.

Not an exact science

Predicting what El Niño will do in Worcester and elsewhere is not an exact science.

Casey, Infante and Rood noted that just because El Niño generally means warmer and drier conditions in the North, that doesn’t mean Worcester and the rest of New England will see that type of weather day in and day out this winter. Sure, there will be warm days with no precipitation. But there could be days with a deep freeze, heavy rains and snowstorms.

In short, there can be variability in weather patterns, because no two El Niños are alike. Plus, El Niño forecasts are based on historical information that is a statistical average, and Mother Nature doesn’t always follow what happened in the past. Or go on averages.

Infante gave examples of this variability, noting the 1983 "Megalopolitan Snowstorm" and the late January 2016 blizzard along the I-95 corridor in what were considered mild winters.

Another case of variability is NOAA's prediction that Massachusetts could experience up to a 40% chance of above-normal precipitation from December to March. That appears to run counterintuitive to El Niño's general take that New England will have a drier winter. Infante explained that El Niño's strong rainfall band in the Southeast can extend up the coast into Massachusetts.

Will we get a nor'easter? There's a caveat

Any discussion of the potential for huge snowstorms during El Niño has to take quasi-biennial oscillation into account. Casey explained this caveat as a band of wind located high in the stratosphere that normally swirls west to east around the equator.

But the direction can shift and that is what happened with this year’s El Nino. The quasi-biennial oscillation is now moving east to west and that can affect the polar vortex. A wavier jet stream can result, and it can send cold air our way.

“A shift in quasi-biennial oscillation can change things into big snows or cold arctic outbreaks,” said Casey.

What will future bring? Let's see what happens

While it would be nice to predict what El Niño will do to our Worcester weather, all we can say for sure is that El Niño is back.

“Until we see what happens, we don’t know if this is an exceptionally strong or super El Niño or not,” said Rood.

“No two El Niño events are the same,” said Infante. “Historical composites can tell us what happens on average, and how often certain impacts occur, but a range of outcomes is always possible."

Contact Henry Schwan at henry.schwan@telegram.com. Follow him on X: @henrytelegram.

This article originally appeared on Telegram & Gazette: El Niño brings unpredictability to winter in Worcester County