- Associated Press - Friday, July 17, 2015

MEDFORD, Ore. (AP) - The white sphere on top of Mount Ashland may be motionless on the outside, but a peek underneath the hood reveals there’s a lot of activity going on.

A 28-foot dish lurks beneath the wintry fiberglass globe of a cover, rotating 24/7 and sending out blink-and-you’ll-miss-it pulses of electromagnetic energy. When the pulses bounce off storm clouds and come back, they contain a plethora of data: how hard and heavy the rain or hail is coming down, air circulation, wind speed. Lightning strikes are tracked separately.

This facility, the Next Generation Weather Radar, or NEXRAD, is the National Weather Service’s lifeline when the thunder rolls.

“The network of these Doppler radars were put in for severe storms,” says meteorologist Ryan Sandler. “For tornadic storms, storms with large hail and strong winds.”

But NEXRAD, going on 20 years, is not immune to Father Time. The National Oceanic and Atmospheric Administration is hoping to extend this station’s life and the network’s 121 others scattered across the U.S. with a $16.7 million budget request from the federal government. If approved, the money will fund repairs and maintenance on the network that was originally installed in the mid-1990s.

Officials say the maintenance would extend the system’s shelf life until the year 2030, when another, more advanced system would be phased in to take its place.

“Without this continued investment, NEXRAD availability will degrade beginning in 2020, resulting in radar outages and gaps and negatively impacting tornado and flash flood warnings,” a budget summary reads.

The upkeep would go toward new receivers and signal processors and pedestal refurbishment. It’s all part of what officials call a service life extension program, or “SLEP.”

“We just want to do a big upgrade and make sure they can last the next 15 years,” says Aria Remondi, NOAA budget analyst.

Sandler says the wear and tear on the stations is to be expected. The dishes rotate constantly and pivot up and down.

“Eventually the whole pedestal and all the gears have to be replaced,” Sandler says. “That’s what they’re thinking is going to happen real soon. And that’s a big deal. You’ve got to remove the dome, that cover, and you’ve got to basically pull the whole radar dish off to replace the pedestal, because it’s underneath.

“It’s a big project. It costs a lot of money, and it’s a lot of effort.”

The SLEP would start in 2016 and conclude by about 2022, the budget document says.

The 122 NEXRAD stations were installed at a cost of $3.1 billion. According to the budget document, they had “an original design life of 20 years,” and the proposed repairs would extend its life by about 15 more, “until the next generation of weather radars is identified, developed and deployed.”

“Like a used car,” Sandler says. “I mean, if it’s 10 years old and starting to break down, you’d rather fix it than buy a brand new car. It’s the same thing.”

The Medford National Weather Service NEXRAD went live in April 1996.

Prior to that, the agency had relied on WSR-57, or weather surveillance radar 1957, the first year it was built. Some of the technology went back as far as World War II.

“It was some old stuff,” Sandler says. “Vacuum tubes, that kind of stuff.”

A WSR-57 system was up on Mount Ashland from 1971 to 1995. Unlike WSR-57, NEXRAD can detect the height and width of individual raindrops and hail stones. It can also estimate one- and three-hour rainfall amounts, used for flash flood and flood forecasts and warnings. WSR-57 system images appeared as murky smudges and dots, while NEXRAD can put out renderings in full color. Storm cross sections are also available to view.

“It really is night and day what we can look at,” Sandler says. “It’s like a CAT scan versus an X-ray.”

It’s a reliable system, he adds, a key resource in keeping tabs on nasty storms. However, the farther out the signal pulses go, the poorer the data. It’s not that great at tracking steady rain that’s falling along the Oregon Coast, for example.

“By the time you get to Brookings, the center of that beam - it goes out as a cone - is almost 15,000 feet above the ocean. A lot of that rain is below 15,000. So it looks like really light rain when it’s pouring out at the coast,” Sandler says.

It’s uncertain what the state-of-the-art system of 2030 and beyond will produce.

“They are doing research right now as to what it would be,” Remondi says. “There’s no outright winner or anything right now.”

___

Information from: Mail Tribune, https://www.mailtribune.com/

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