New weather radar better tracks violent storms
Monday , March 19, 2012 - 10:03 AM
NEXRAD Radar at the WSR-88D Radar Operations Center...
FORT WORTH, Texas -- Faster and more precise storm detection radar will get its first urban test this spring in Dallas-Fort Worth, mapping weather hazards down to street levels when tornadoes, high winds or flash floods threaten.
"This is absolutely lifesaving technology," said Molly Thoerner, director of emergency preparedness for the North Central Texas Council of Governments.
The near-ground radar system, which will supplement the current NEXRAD Doppler radar network, will provide faster scans, higher-resolution images and multiple overlapping views of storm cells, said Bill Bunting, chief meteorologist for the National Weather Service in Fort Worth.
"What we're excited about is that the radar data will help us better detect damaging winds and small circulations of brief tornadoes. The other thing that it does very, very well is estimates of rainfall. So we can use that to issue more precise flash flood warnings," Bunting said.
"Wind storms and tornadoes, especially the shorter-lived ones, we expect to see those and get the word out with at least a few minutes of advanced notice, whereas now it's hard to do much at all," he said.
Four of the radar units will be installed this spring in a ring around the Metroplex: Fort Worth, Addison, the University of North Texas and the University of Texas at Arlington.
"We'll have four new looks at a storm," Bunting said, adding that four more units will be installed to broaden the coverage area before the 2013 storm season.
The new radar was proved during a four-year test in rural southwest Oklahoma, said Brenda Philips, a co-leader of the project developed by the Engineering Research Center for Collaborative Adaptive Sensing of the Atmosphere.
Funded by a National Science Foundation grant, the $40 million, 10-year project is made up of a consortium of nine universities, government agencies and industry partners, Philips said. Engineers at the University of Massachusetts Amherst have been leading the project since 2003.
Steve Chapman, emergency management director for Chickasha, Okla., said CASA radar is "a great thing. We hated to lose it."
"We were able to dissect thunderstorms down to a very minute detail," he said. "The biggest advantage is that it updates quicker than Doppler radar and you get to look lower in the storm because the farther you are away from the radar site, the higher it looks."
Dallas-Fort Worth's 6.5 million people and volatile weather made it the perfect urban test site for CASA's next five-year study phase.
"What we were looking for was a large enough metro area and one that experiences a variety of hazards, and you guys really get it all -- floods, tornadoes and remnants of hurricanes," Philips said.
DFW will also serve as a model for establishing public-private funding partnerships to cover the radar's costs, she said, noting it would eventually take 16 to 20 CASA radar systems to cover the 16-county Council of Governments area.
CASA is footing the approximate $4 million cost of the initial eight radar systems.
Local entities are responsible for the first year's operating cost, $500,000; the cost is expected to decline in the second year.
"It's a great deal for the Metroplex," Philips said.
She noted that the nation's current radar network was funded by billions of federal dollars. But "we're not in a situation now -- politically or economically -- where that is going to happen. What we're trying to do is pilot a whole new way of establishing a safety infrastructure where you have the local community engaged -- a local, private-public partnership."
The Council of Governments is working to fund the new network's operational costs, including seeking private partners who could utilize the weather data, Thoerner said.
"It would be a perfect opportunity for a company developing apps for phones. It could help the construction industry, utilities, hospitals and the logistics industries -- rail, trucking and aviation," she said.
The beauty of the white-domed $500,000 radar units, which are mounted on cellphone towers, is their low cost and small footprint compared with $4 million for each of the 159 radar units in the NEXRAD network, Bunting said.
CASA can fill in the gaps in the current warning system, made up of Doppler radar and weather spotters.
Because of Earth's curvature, Doppler radar can't observe the lower atmosphere, while CASA can scan as low as 250 meters -- about 250 yards -- above ground, Bunting said.
Frequent high-resolution radar observations can pinpoint storm activity down to a tenth of a square mile, Philips said.
That sort of precise warning will give people a better idea if they are in harm's way, said Juan Ortiz, Fort Worth's emergency management coordinator.
"It should result in a reduced number of false warnings. It is really going to create something that is going to save lives and protect property in our community," he said.
Doppler radar scans the atmosphere every four or six minutes; CASA can scan every 60 seconds.
"It will give us better ability to see small-scale damaging wind events and flash-flood events in more detail than we've seen before," Bunting said. "We will know where the heaviest rains are falling compared to what we do now."
Instead of issuing a flash flood warning for a two or three-county area, an alert could be narrowed to smaller drainage basins or streams, he said.
The CASA idea, Bunting said, is to pull the radar data into computer models that forecast how storms are expected to evolve over several hours.
"That has benefits for public safety in general. If you have a big outdoor festival going on, you can be fairly specific on where the impacts will be. That's a little longer term, but that can be started fairly quickly.
"Our vision for sometime in the future is to be able to issue a warning based on a prediction for a storm that has not yet developed."
That potential is generating wider interest, Thoerner said.
"We're already hearing from other areas of the country who want to know when they can get it."
(c)2012 the Fort Worth Star-Telegram
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