Winter's demise unfounded, but don't count out warming

In deep, Paul Hafner clears his father's Cherry Hill walk. While experts debate climate change, for businesses, the costs are still piling up.
In deep, Paul Hafner clears his father's Cherry Hill walk. While experts debate climate change, for businesses, the costs are still piling up. (DAVID M WARREN / Staff Photographer)
Posted: February 17, 2014

After last week's megastorm that solidified the legacy of the winter of 2013-14, one meteorologist confidently pronounced: "The back of winter is broken."

If that, indeed, is the case, those who have been shoveling the thousands of pounds of this stuff or have spent days without heat or lights likely would agree that winter is getting precisely what it deserves.

"It's been a long, cold winter," said Bruce Terry, senior forecaster at the government's National Weather Center, in College Park, Md. "If you like snow, it's a bonanza."

A weakish snowfall Saturday accounted for an official six-tenths of an inch, tying this winter with 1898-99 at 55.4 inches, the third snowiest in the region's history. Through Friday, 54.8 inches of snow had been measured at Philadelphia International Airport, which made it the fifth-snowiest winter in the 130-year period of record-keeping.

Jeff Masters, meteorologist at the popular Weather Underground site, and the one who claimed that winter's back "is broken," suspects our weather might be related to cold water immediately off the West Coast, and may have something do with worldwide warming.

Terry was more circumspect: "I don't think we can attribute this to anything."

Whatever the causes, the sequence of storms has made mockeries of highway department budgets, school calendars, and those seasonal forecasts that had called for a gentle winter. It also has stoked anew discussions about climate change, as in, We thought winter was extinct.

Millennial readers and other relative newcomers might not fully appreciate just how extraordinary recent winters have been around here.

Counting this season, which isn't quite over, by the way, this has been the snowiest five years in the period of record, with a little more than 183 inches. That's about 15 feet, or a yard per winter, despite two seasons in which the combined total was barely one foot. The average is about 22 inches.

This marked the first Philadelphia winter in which four storms of eight inches or more fell in a single season.

Never have the snows of yesteryear looked more appealing.

The watchword

Teasing out precisely what the incremental warming of the planet has to do with local weather is problematical, but Masters believes it is a player.

"At this point, you need to expect the unprecedented," he said. "That's my watchword for the future."

Masters holds that the recent presence of open water in the Arctic, the result of ice melting, could be interacting with the atmosphere in such a way as to affect air patterns.

That might hold water, said Deke Arndt, a researcher at the National Climate Data Center, in Asheville, N.C. But he wants to see more evidence and how it holds up to scientific scrutiny.

"I'm interested in seeing how that research plays out," he said, but "it hasn't really walked the plank yet."

Scientists caution that global warming isn't a spectator sport; so far the warming has been incremental.

During the relatively warm period of the last 30 years, global temperatures have increased at the rate of about 0.025 degrees Fahrenheit per year, or 0.25 degrees per decade, according to both the National Climate Data Center's analysis of surface stations and NASA's satellite data. In records dating to 1880, the annual change in either direction has never exceeded 0.5 degrees.

The warming is forecast to continue, but rumors of winter's extinction have been greatly exaggerated; the Arctic has plenty of cold air left, Masters said.

That air has been a frequent visitor this year. Masters said that chilly water along the U.S. and South American west coasts could be behind the strange behavior of this season.

Idiosyncratic

To simplify, cold West Coast water generally correlates with a ridge, or high pressure in the West, which promotes warmth and dryness, and a mirror opposite trough in the East, which favors storms and cold.

But Terry observes that the snow in the Philadelphia-New York corridor has been idiosyncratic - in ways that couldn't be captured in a seasonal outlook.

Severe winters typically are characterized by "blocking" upper-air patterns in the North Atlantic that end up damming cold air in the U.S. Northeast. But not this year.

In January, cold and storms were tied to the "polar vortex." That spinning mass of arctic air, which became a media celebrity last month, has since returned to the obscurity it had enjoyed for millennia.

Some of the local snows have come from "clipper" systems from the West, usually not big snow-makers around here. Last week saw the first real coastal snowstorm of the season.

Arndt cautioned that snow, given its relative infrequency on the planet, isn't a strong indicator of climate change. He pointed out that while last week's storm affected one-third of the country, that represented less than 1 percent of the planet.

Scientists describe the atmosphere as a "nonlinear chaotic system"; it is a three-dimensional fluid sloshing on a sphere spinning 1,000 m.p.h. and heated at varying intensities by the sun.

This week, it appears that some warm air will slosh this way, with the Big 5-0 temperature possible by Thursday.

Said Masters, "Relief is coming," not that he's complaining about all the cold and snow he's endured in Michigan this season.

"If you're going to have winter," he said, "you might as well have winter."


610-313-8210

twood@phillynews.com

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