Blizzard's coming: Will records fall?

The region braces for what meteorologists warned could be its first all-out blizzard in at least 20 years, with thunder, lightning, "gravity waves," whiteout conditions, coastal flooding, and one of the biggest snowfalls in 132 years of recordings.

Hours before the first flake sightings in Philadelphia, the monstrous nor'easter was taking shape. Airlines canceled more than 6,000 flights, from Charlotte, N.C., to New York City. There will be no flights in or out of Philadelphia, and SEPTA also suspended Saturday service.

Computer projections Friday had meteorologists declaring that what had seemed all week to be a major threat would perhaps turn even more menacing.

"The models are angry, my friends, very angry," tweeted Gary Szatkowski, meteorologist in charge of the National Weather Service office in Mount Holly.

Blizzard warnings took effect for the Baltimore-Washington area, where snow started falling Friday afternoon, and along the I-95 corridor from Wilmington to Manhattan. Snow moved into the Philadelphia region about 7 p.m., and by 11 p.m. some areas were reporting 2 inches on the ground. The weather service predicted 20 inches in and around Philadelphia, and said the snow on Saturday would be the wet-heavy variety that can be the bane of utilities and their customers.

"We are concerned that there will be widespread power outages with this storm," said Alyson Hoegg, a meteorologist with AccuWeather Inc.

Gov. Christie, campaigning in New Hampshire, said he would fly back to New Jersey for the storm. Pennsylvania, where Gov. Wolf has declared a state of emergency, activated its emergency center Friday. Just about every municipality with a working government, including Philadelphia, declared a snow emergency.

And if you hoped to attend almost any event Saturday, consider it canceled. Among the casualties was the annual Academy of Music Anniversary Concert and Ball, a tradition since 1957 - a first-ever cancellation.

You can't even take a walk in a Montgomery County park; all of them are closed. Not only was the Scrapplefest at the Reading Terminal canceled, the entire market decided to shut down.

With a full moon swelling the surf, and high tides coinciding with the storm's peak ferocity, the weather service said major coastal flooding was possible.

But no one could complain about a lack of warning.

With a possibly unprecedented steadfastness, according to Louis W. Uccellini, a snowstorm expert who heads the National Weather Service, the world's major computer models have been seeing a potential megastorm for several days.

"We are ready for this storm because we've had so much advanced warning about it," said Rich Peterson, a spokesman for Ocean County, N.J., where beach towns were mutilated by Sandy in 2012 and where portions of Barnegat Light were evacuated Friday.

AccuWeather's Hoegg said bands of heavier snow would set up from Washington to Philadelphia to New York.

"Some area is going to get mauled out of this," she said, with a potential for up to 30 inches.

In addition to banding, "gravity waves" - powerful disturbances in the upper atmosphere that can generate profoundly heavy snow - are possible, said Uccellini, who has called the coming storm a "potentially paralyzing" blizzard.

During a storm, the atmosphere, a three-dimensional fluid, can behave like a stormy ocean, with rising and falling waves. Snow forms when warm air rises over cold air, and when air is rapidly rising, it snows heavily. The waves can extend for a few hundred miles, affecting a narrow corridor.

Meanwhile, the air away from the wave crest has to sink, aided by the pull of gravity. Snow in those areas lightens, but they are subject to potent winds that can create whiteout conditions.

"That's a phenomenon reserved for intense storms such as this," said Lance Franck, a meteorologist at the local weather service office. Throughout the region government, utility and transportation officials said they were prepared.

If the storm does qualify as a blizzard - that is, winds of 35 m.p.h. or visibilities of a quarter-mile or less - it would be the first in Philadelphia in at least 20 years.

The 30.7-inch snowstorm of Jan. 7-8, 1996, did not quite qualify, but the conditions were so extreme that the weather service did log it in the record books as a blizzard, said meteorologist Tony Gigi, now retired from the weather service.

The March 1993 "superstorm" did meet the criteria.

Whatever comes, Mayor Kenney offered the following recommendations:

"I suggest Netflix, pay-per-view," he said. "Make sure you're all stocked up. Enjoy being home, and don't go out until it's really safe to go out.

"We'll give you the all clear."

twood@phillynews.com610-313-8210@woodt15

Staff writers Michaelle Bond, Tricia L. Nadolny, Mari A. Shaefer, and Jacqueline L. Urgo contributed to this article.

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