As Philadelphia inches toward a snow-deprivation record that no one saw coming this time last year, the local TV meteorologists all have weighed in with their scientific reasoning and entertaining discussions to explain their estimates. They happen to track well with those publicly released by major commercial services.
But among those guaranteed not to be wrong about this season’s snow total is NBC10′s Glenn Schwartz: For the first time in 24 years, he isn’t issuing a winter outlook. Also whiff-proof in the snow department are The Weather Channel and the government’s Climate Prediction Center: They are eschewing that precarious limb.
Mike Halpert, the Climate Center’s acting director, says that given the daunting limits of predictability, forecasting seasonal snowfall is skating on thin scientific ice. That said, he added that he understands why stations do it.
“It’s ratings, man,” he said.
Philadelphia’s average snowfall is around 22 inches, but 135 years of data reveal a jumpiness in annual totals that is borderline hallucinatory. They don’t even track that well with temperature, something that snow expert Dave Robinson, the Rutgers University who is the New Jersey state climatologist, has observed.
That erratic behavior has been especially evident in recent years, and climate change might well be an agent provocateur. That’s one reason Schwartz cited for passing on the winter of 2020-21.
The region has been experiencing a remarkable snowless stretch. It has been 643 days since the last time an inch of snow was measured in Philly, dating to March 2019.
Perhaps surprisingly, that’s not a record — yet. Not an inch fell from Feb. 20, 1972, to Dec. 15, 1973, 665 days.
Schwartz said climate change has crashed his seasonal forecasting technique. “The world is so different from the way it used to be,” he said. “My recent forecasts have generally not worked out.”
But another factor this year was the cosmically somber avalanche of news. “In the end, it was very much an exercise in entertainment,” he said.
In snow records dating to 1885, Philadelphia’s official totals have ranged from a “trace,” in other words nothing, to 78.7 inches 11 winters ago.
The first-snow date has varied from Oct. 10 in the winter of 1979-80, to never, in the 1972-73 season. In any given season, one storm can skew the total radically. The winter of 1982-83, for example, finished in the top 20 for snow with 35.9 inches, but a season’s worth, 21.3, fell in one February blizzard.
Aside from snow, basic precipitation is a tougher variable than temperature, which is tough enough, and in some years snow and temperature appear to have an adversarial relationship.
In the winter of 2009-10, the one with the 78.7 inches, not a single decent cold spell — one with four straight days in which the temperature didn’t get above freezing — occurred. It finished in the middle of the pack for winter temperature.
The winter of 1959-60 was among the 50 coldest, yet produced only 5.1 inches of snow. Temperatures in the snow-less 1972-73 season were close to average.
One of the warmest 10-year winter periods on record, ending with the winter of 2017-18, was the snowiest, with an annual average of 31.9 inches. The 10-year period that ended with the 1931-32 season was almost as warm, and the average winter snowfall was a mere 13.2 inches.
An unusual consensus has coalesced among meteorologists that the winter of 2020-21 is going to be a dud here and elsewhere in the nation for snow and cold.
“This is not a pattern that supports much snow,” Cecily Tynan told her viewers. Her colleague Adam Joseph allowed that all the long-range models were in agreement in calling for a mild winter. Tynan said the best Philly could hope for was “nickel and dime” snowfalls.
Last season, the consensus was quite the opposite.