What Pacific winds say about Connecticut’s winter

The Pacific Ocean winds are pushing its equatorial waters westward, toward Java and Sumatra.

So, wind and weather permitting, expect New England — a half world away — to be mild and rainy rather than cold and snowy.

Unless, of course, changes off Iceland or the North Pole have their say. Not to mention the Madden-Julien Oscillation.

All of this is to make it clear that long-range weather forecasting is fraught with ifs and maybes.

What we do know now is this: There is a La Nina — and a strong one — brewing in the Pacific Ocean.

“In the last 70 years, this one is ranked number 8,” said Michelle L’Heureux, climate scientist with the US Climate Prediction Center, which is part of the National Oceanic and Atmospheric Administration. “Statistically, it’s one we would get every 10 years or so.”

La Nina, the Little Girl, means that the central and eastern waters of the Pacific Ocean are colder than normal. It’s the reverse of an El Nino — the Little Boy — when the Pacific’s waters warm up.

La Nina winters occur when winds blow the warmer surface waters of the Pacific Ocean near South America to the west toward Indonesia. Cold water from lower depths rises to take its place.

Often, the two phenomena occur in succession: an El Nino followed a year later by a La Nina.

L’Heureux said this year is unusual. Not only is the

La Nina a strong one, but also it’s occurring after a normal, neutral year before it.

La Nina years make the southern tier of the country warm and dry, while making the northern tier colder and, hence, more snowy. That’s especially true in the Northwest Pacific states and the northern Plains.

Normally, La Nina effects don’t reach us.

“The East Coast is a wild card,” L’Heureux said.

“It washes out before it reaches New England,” said Bill Jacquemin, senior meteorologist with the Connecticut Weather Center in Danbury.

But he said that this year could be different. Combined with overall trends showing East Coast winters getting milder, the Climate Prediction Center is forecasting La Nina could warm temperatures from southern California east, up the entire East Coast to

Maine.

“We are fairly confident of La Nina,” said Randy Adkins, a meteorologist with AccuWeather, the regional weather forecasting center in State College, Pennsylvania.

However, local meteorologists are unconvinced by this call.

“I know everyone is calling for a mild winter,” said Gary Lessor, director of The Weather Center at Western Connecticut State University in Danbury. “I’m not 100 percent sold.”

Lessor allows that, by and large, we’ve had a warm November. That points to a winter, which for meteorologists runs from Dec. 1 to Feb. 28, that may be mild as well.

But there are large, unpredictable changes that can disrupt these trends.

Lessor said one of these is the Madden-Julian Oscillation, discovered in 1971 by American meteorologists

Roland Madden and Paul Julian. It’s a traveling weather pattern, moving east to west across the Indian Ocean and western Pacific Ocean, alternating between cycles of rainy and dry weather.

It can show up in North American in winters when one storm follows another and the snow never ceases. The winter of 1995-96 was like that, dumping more than 100 inches of snow on the state.

There are two other oscillations to contend with. There’s the North Atlantic Oscillation, an atmospheric pattern that develops over the North Atlantic Ocean from Iceland to the Azores. When it’s in its positive phase, winters in eastern North American can be wet and warm. When it’s in its negative phase, the winter winds blow cold and the people who plow snow for a living go to work.

And there’s the Polar

Vortex, the swirling mass of frigid air that spins around the North Pole and, on occasions, pushes south into the United States, inducing frostbite.

L’Heureux said the problem with these oscillations and vortexes is that meteorologists can’t predict them until about two weeks or so before they begin. They also aren’t long-lived. So we could have a mild, La Nina winter, with a crash or two of very cold weather along the way.

Jacquemin said he’s expecting a cold December, a January thaw, a normally miserable February and wetter March and April. Add to that the cabin fever brought on by COVID-19, he said, and people may really feel the winter in their bones this year.

“It’s a psychological thing,” he said.