Local meteorologists seeing big picture with new radar

As the storm known on social media as #gobblegeddon swept toward Pittsburgh on Monday, local meteorologists consulted their computer models to predict its impact on holiday travelers.

Unlike the "Snowmageddon" -- are we sensing a naming trend here? -- of February 2010, however, they now have a new technology at hand.

Nearly 30 years in development, the National Weather Service's "dual polarization radar" doesn't just detect precipitation and determine its movement, as with conventional Doppler radar. The "dual pol" system creates a two-dimensional picture that can identify different sizes of raindrops, hail, snow, ice pellets and other flying objects, including insects.

Pittsburghers greet snow with shovels and smiles

The Pittsburgh region woke up this morning to a blanket of snow. (Video by Nate Guidry; 11/26/2013)

"It sends a pulse out in two different planes, a horizontal plane and a vertical plane," explained Jack Boston, expert senior meteorologist with AccuWeather in State College.

The dual pol system is installed at 160 sites throughout the U.S. at a cost of $50 million. According to the NWS, researchers estimate it could save the federal government $700 million annually by reducing weather-related damages.

The technology can also be used to track tornadoes and other severe storms by identifying flying debris.

Pittsburgh was an early adopter of dual pol, which was available here about two years ago. That was too late for the big winters of 2010 and 2011, but the arrival of #gobblegeddon appears to be a perfect test case because of its complex mix of elements.

"Absolutely," said Jeff Verszyla, KDKA-TV chief meteorologist. "Not only are we dealing with various types of precipitation, it's playing havoc with [forecasting] the amount of snowfall, which is one of the main things people want to know."

The first edges of the storm arrived in the wee hours of Tuesday, bringing a coating of snow, some rain, and a lot of headaches. A bigger wallop of pure snow was expected to move into the region overnight, when frigid air from the northwest ran into a large system of moist air from the south.

The National Weather Service said 2 to 3 inches of snow would fall by 6 this morning, with another 1 to 3 inches possibly coating the region today. Thanksgiving Day may see some light flurries and will remain chilly, topping out at 28 degrees.

Each of the three local television stations has its own weather tech, with WTAE recently installing Weather Systems International's "Max Weather" computer graphics program. Real-time radar pictures are rendered in a choice of models.

"Whereas before you might be stuck with one model, whether it was right or wrong, now we can use one of six, or maybe one of eight," said Mike Harvey, the station's chief meteorologist.

WPXI-TV news director Mike Oliveira said the technologies have grown over recent years, but so has the demand for up-to-the minute weather coverage.

"Echopath" is a future radar scan that helps predict when rain will turn to snow, up to two hours in advance. "That's huge, in a situation like today," Mr. Oliveira said.

WPXI also draws on information from its Traffic Tracker system, which has sensors in the air and road surfaces to determine temperature and detects potentially hazardous road conditions. The station also crowd-sources weather conditions via social media, asking viewers to post photos using the #wpxistorm hashtag.

By Tuesday morning, images included snow-covered buildings at Washington & Jefferson College, an icy Forbes Avenue near the University of Pittsburgh and a ruler displaying 4 inches of snow in North Huntingdon.

"It allows us to take those pictures and stream them on television or the website immediately. It works really well for breaking news and weather situations because we can get those pictures to the viewers before we get a live truck set up," Mr. Oliveira said.

PennDOT's traffic cameras can be accessed by the stations, which of course provides a live look at road conditions. Mr. Verszyla said that tech is great, but it's also nice to have the visuals.

"It's always good to have eyes," he said. "Eyes never lead you astray."

Maria Sciullo: msciullo@post-gazette.com or 412-263-1478 or @MariaSciulloPG.

First Published November 26, 2013 7:38 AM

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