Improved Forecasts Headed This Way

National Weather Service getting better radar technology

Pittsburgh Post-Gazette
4 July 2011
By Lauren Rosenthal

Cutting edge weather forecasts are about to hit the Pittsburgh area before the rest of the country -- but don't expect to see space-age satellites dotting local farmland or glitzy new maps on the evening news.

Dual polarization radar technology will be installed near the National Weather Service office in Moon beginning Wednesday. When the installation -- which requires technicians to replace a few parts in the doppler radar systems that have sat at the NWS station for more than a decade -- is complete, local meteorologists will start using the radar to deliver more detailed and accurate forecasts. Installation takes about 10 days.

Pittsburgh is one of five beta testing sites to receive the radar, which emits signals in both horizontal and vertical directions. Traditional doppler radar emits only horizontal signals. Dual polarization radar is scheduled to be installed at every NWS station by 2013.

"We're lucky!" said Richard Kane, meteorologist in charge at the Pittsburgh NWS office. "The opportunity came along for us and we decided to take it."

Because of its wealth of rivers, lakes and streams, Western Pennsylvania is vulnerable to floods, Mr. Kane said. Though doppler radar can help predict the likelihood and severity of storms, the single horizontal pulse prevents forecasters from gauging how large the raindrops are and how quickly they will fall -- crucial information for predicting flash floods, Mr. Kane said.

Dual polarization radar will provide that level of detail, resulting in improved flash flooding alerts and increased warning time for residents in flood zones, he said.

Though tornados are less common in the greater Pittsburgh area than in Norman, Okla., another beta test site for the dual polarization radar, KDKA-TV Chief Meteorologist Jeff Verszyla said Western Pennsylvania residents will still benefit from improved tornado warnings.

Mr. Verszyla pointed to a tornado that unexpectedly hit Westmoreland County in March with 120 mph winds as a prime example.

"In that particular case, the dual polarization radar would have given us a higher degree of certainty that a tornado was occurring on the ground," Mr. Verszyla said. "It would have given a heightened sense for people within the path of a storm that they needed to take appropriate action."

Dual polarization radar is more sophisticated than doppler radar, but Mark Hamilton, an electronics technician at the Pittsburgh NWS office, said the new system doesn't require any additional maintenance. Mr. Hamilton said he and other technicians will be keeping an eye on the radar to learn which parts burn out fastest.

"It's like getting a brand new car," Mr. Hamilton said. "You assume it's going to last, but new cars have problems, too. The new sites are going to help us gather that information."

Dual polarization has one immediate drawback: The Greater Pittsburgh area will be without radar while the new system is installed. The NWS will rely on radar from the Federal Aviation Administration as well as NWS outposts in State College, Centre County; Cleveland; Wilmington, Ohio; and Charleston, W.Va., to make predictions for the Pittsburgh area.

"The chances that we'll get severe weather between July 6 and July 16 -- well, it's a pretty good chance," Mr. Kane said.

Mr. Kane said he expects the patchwork radar to work well: The NWS used the same plan when the Moon radar system broke down last summer.

Lauren Rosenthal: lrosenthal@post-gazette.com.