The giant eyeball atop 7,533-foot-high Mount Ashland is asleep.

The giant eyeball atop 7,533-foot-high Mount Ashland is asleep.

A team of technicians contracted by the National Weather Service to upgrade the circa-1996 Doppler radar system shut it down Friday to begin installing state-of-the-art dual polarization technology.

When it is awakened near the end of this week, the radar system will be able to better see weather patterns developing in southwest Oregon and northwest California.

"With this new system, we will be able to see things like the liquid water in an updraft in a thunderstorm," observed Ryan Sandler, warning coordination meteorologist at the agency's Medford weather station, during a visit to the mountaintop.

"Dual polarization will be able to show us the long shaft of water droplets," he added. "And that's what we look for in a thunderstorm. We're looking forward to using it."

The upgrade will enable the radar to collect data on the horizontal and vertical properties of weather, he said, noting the old system featured only the horizontal.

"Before, with just the horizontal, we were only able to see how fat the raindrops were," he said. "Now we'll be able to see how tall as well as how fat it is. We will know the different shapes, and know whether they are raindrops, hail or snow."

In addition to the telltale shape, forecasters also will be able to determine the distribution more accurately, he said.

"We will know how hard it is raining," he said. "That will help with river flood warnings and flash flood warnings. Our precipitation forecasts will be greatly enhanced."

The radar site is one of 122 the agency is upgrading nationwide, as well as 38 similar Doppler sites operated by the Air Force and the Federal Aviation Administration, at a cost of about $50 million. The work is being done in a partnership by L-3 Stratis based in Reston, Va., and Baron Services Inc. out of Huntsville, Ala.

Before the Doppler system was installed on Mount Ashland in 1996, a smaller radar unit put in place in the early 1970s served as the eyes and ears for the weather service.

Known as a "radome," the mountaintop sphere is 28 feet in diameter. Inside is a spinning radar dish which is just slightly smaller than the dome.

Underneath the dome is a concrete bunker chock full of computer hardware, including a radar data acquisition unit whose mission it is to gather the information from the radar and transmit it to the NWS weather station near the Medford airport.

When the power is knocked out atop the mountain, a backup generator system kicks in, powering the site for over a week.

The workers will remove a fiberglass panel with the aid of a cherry picker, then carefully bring the new hardware in through the "window," explained Matt Wymore, an NWS electronic technician specializing in radars who has been helping maintain the site for 11 years. One item that will be installed weighs some 400 pounds, he noted.

"They will take the older radar components out, specifically the receiver, and refit the system with the new technology," Wymore said.

"We estimate the system will be down around a week," Sandler added. "Unfortunately, we think there will be some thunderstorms around here while the radar is down."

But the service will fill the gap with satellite weather tracking systems and other means.

"We won't be able to see the details of any storm over the next week," Sandler said Friday.

Yet the upgraded system with its new hardware and software will be worth the short downtime, according to the agency.

"This radar network was primarily designed to capture severe weather," Sandler said. "That was its No. 1 priority."

While the high elevation of the radar site may make it difficult to "see" low-elevation rainstorms, the radar has no problem focusing on thunderstorms whose anvil-shaped clouds may rise 40,000 to 50,000 feet above sea level, he said.

Reach Mail Tribune reporter Paul Fattig at 541-776-4496 or email him at pfattig@mailtribune.com.