Philly’s lack of snow cover is about to set a record, in another mild winter

Barring a snow blitz and a decent cold spell or two in March — and computer models aren’t seeing either right now — Philadelphia is about to set a new standard for snow scarcity.

Officially, Philly will have had fewer days with observed snow cover in the last 10 years than in any similar period since the National Weather Service began taking measurements at Philadelphia International Airport in the winter of 1940-41.

Overall, it has been a decent run for those who view winter as a pre-spring hazing ritual, but for snow-lovers, this has been the definition of tough sledding. And temperatures are due to rocket into the 60s again Wednesday. (Is the groundhog gloating?)

The Dec. 1-Feb. 29 meteorological winter of 2023-24 has all but clinched 10th place on the all-time Philly warm list in records dating to 1872, Eric Hoeflish, a meteorologist with the National Weather Service Office in Mount Holly, said Tuesday. The winter of 1879-80 would fall to No. 11.

» READ MORE: Winters around have become milder during the last half century

With the current seasonal snow total at 11.2 inches, this likely will mark the sixth winter of the last 10 with below “normal” snowfall, which is 23.1 inches.

And the rising sun evidently hasn’t been beaming over snow covers very often in recent years. An inch or more of snow has been observed on the ground at the airport at 7 a.m. — how the weather service reports snow cover — only nine times this winter. The long-term average for the season is about 15, and that number has been exceeded only twice in the last 10 winters.

The annual snow-cover average for those 10 seasons has been 9.4 days. The previous record was 9.9 in the decade ending with the winter of 1958-59.

Although the balmy winters of 1931-32 and 1889-90 are out of reach, this will be the fourth in the last 10 to finish in the 10 mildest. The average temperature was 39.7 degrees as of Tuesday, said Hoeflich.

Hoeflich added that it’s also going to finish as the fourth wettest winter by the time the latest batches of rain shut off Wednesday night or early Thursday and it turns cold for an entire day.

While warmth and wetness are two climate-change calling cards, meteorologists caution that snowfall is a more-elusive indicator, given that it can be so random, and that a single storm can boost a seasonal total to near or above normal.

For example, snowfall in Philly in the winter of 2015-16 was above normal at 27. 5 inches; however, 22.4 of that came in one January storm. Allentown is one place that has had near-normal snow this season, largely because it got caught under a renegade snow band on Feb. 13 and got clocked with over 9 inches.

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The current 30-year “normal” snowfall in Philadelphia, calculated based on the 1990-2020 period, is higher than the long-term average in the period of record.

The snow-cover data may be more representative of the character of the winters, but it is by no means perfect. Those measurements are taken at the airport, which is near the Delaware River and a swamp. Since the station was relocated to the airport, it has had at least three different measurement contractors, and for a period the totals actually were reported from across the river in National Park.

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However, the airport does have a long record set, and there are “too few stations that take consistent snow depth” observations, says David A. Robinson, the Rutgers University professor who is the nation’s longest serving state climatologist and an international expert on snow cover.

The warming world isn’t the only variable affecting snow around here, said Paul Pastelok, the veteran long-range forecaster for AccuWeather Inc. “There are other things to blame,” he said.

Clusters of mild and snow-deprived winters have occurred in the past, and Pastelok said those could have been related to ponderous changes in the oceans, where temperatures aren’t nearly as jumpy as they are on land.

» READ MORE: In Philly winters, expect anything

This winter, the persistent El Niño warming over vast expanses of the equatorial Pacific overwhelmed portions of North American with warm air, erasing snow cover to the north and west of region and shutting off cold air, he said.

The equivalent of a “marine heat wave” north of Hawaii may have contributed to the persistent, warmth-bearing west-to-east winds in the upper-atmosphere, he added. Despite those snows out West, across the contiguous United States this could become one of warmest — or the warmest — winter on record.

With the oceans warming, particularly in the midlatitudes, said Pastelok, more moisture has become available for storms. “We can get more snow, but less frequent,” he added.

» READ MORE: Monster snowstorms have been a relatively modern development

Philly’s snow records date to the winter of 1884-85, and five of the 10 biggest snowstorms have occurred since 1996.

The weather tends to come “in cycles,” said Pastelok. “Are those cycles changing? That’s what’s challenging to us.

“We’re changing the climate. ... Now we need new examples in a new climate era.”