Try spinning a 28-foot radar dish millions of times for 24 years and you'd get a bit worn out, too.

The radar at the National Weather Service office at Wakefield in Sussex County is back in service this week after a major mechanical problem forced it offline on Feb. 14.

Meteorologists rely on its constant 360-degree scans to see the subtle shifts between rain and snow, measure flooding downpours from hurricanes, and issue early warnings for severe storms from the Piedmont to the Eastern Shore.

 

"It's only shut off for maintenance or if there's a problem," said Jeff Orrock, meteorologist in charge at the Wakefield office.

Since the Wakefield radar went online in 1994, the other extended outages were due to a damaging lightning strike in 2009 and a major — but planned — technology upgrade in 2012.

Wakefield is home to one of the 159 "WSR-88D" or "NEXRAD" Doppler radars operated by the National Weather Service throughout the United States and its territories.

Other NWS radar sites near Raleigh, Blacksburg, Washington and Dover provided a partial but less-detailed view of our local weather for the past three weeks while Wakefield awaited a fix.

In February, the bull gear — one steel ring that turns inside another using ball bearings — failed and prevented the motor from spinning the radar around on its pedestal.

The repair couldn't be done immediately or with on-site tools.

A team of six National Weather Service technicians had to travel from Oklahoma to work on the problem last week.

That involved hoisting heavy equipment to the 83-foot high platform that holds the dome, then jacking the huge parabolic dish up to replace the parts that usually hold its weight.

"It's a dangerous job," said Orrock.

The technicians returned the radar to service on Tuesday, a few days ahead of schedule.

Several other NWS radars have encountered the same problem in recent years, including the Floyd County radar operated by the weather service's Blacksburg office.

It's a sign of age: The NEXRAD radar network was designed in the 1980s and installed in the early-to-mid 1990s.

Under the hood, under the dome

Travelers on U.S. Route 460 can spot the red-and-white metal radar tower tucked into a clearing in the pine forest northwest of Wakefield.

Access is only for technicians — and only when the radar isn't powered up — though mud daubers are known to find their way up to the lofty perch.

Wednesday's quiet weather provided an opportunity to accompany electronic systems analyst Ron Boyle up the grated, wind-swept metal stairs and through the hatch for a very brief look at the repaired pedestal.

There isn't much clearance between the large dish and its protective fiberglass dome, which filters bright sunlight into an amber shade.

Voices and metal clangs take on odd resonance inside the spherical enclosure, and the air hangs still and cool like an auto garage.

Most of the time — about 99.9 percent of the time — that large dish is spinning.

Spinning and listening.

A transmitter in a nearby building feeds rapid microwave pulses up to the antenna, and the huge reflector dish collects the signal sent back by distant rain, hail, snow or sleet into a receiver.

Even when there isn't any active weather, it scans in "clear air mode" and can continue to detect anything that happens to be in the sky, such as large flocks of birds, insects, or smoke plumes.

When there are dangerous storms, operators switch the radar to spin faster and gather data at extra altitudes.

All of that scanning and tilting gradually takes a toll on the electronic and mechanical components, and it's already past its designed 20-year service life.

Later this spring, the transmitter component is scheduled to be replaced, and sometime in the next few years an overhaul of the pedestal itself is aimed at extending the radar's operation well into the 2020s.

Upgrading the U.S. radar network to more advanced phased array technology could be decades away.

 
 

Check Richmond.com/weather for John Boyer's videos and updates as the forecast evolves. Contact him at (804) 649-6209 or JBoyer@timesdispatch.com, and follow him on Twitter, @boyerweather.