Weather radar goes offline for 2 weeks

For two weeks starting Monday, Central Arkansas’s main weather radar will be silent.

KLZK, a WSR-88D radar operated by the National Weather Service, will be offline as it undergoes critical upgrades.

Located at the North Little Rock Airport and first built in the early 1990s, the pedestal on which the radar dish sits will be replaced for the first time in an effort to extend the life of the radar.

“Basically, there’s a big dish in the radar dome, and that dish sits on top of a pedestal, and that pedestal rotates,” said Willie Gilmore, a meteorologist with the National Weather Service in Little Rock. “Virtually 24/7/365 that dish is running.” The WSR-88D radars were originally designed to last 25 years.

The refurbishment is the third step in a four-step project to refurbish all 159 radars that make up the NWS network across the country.

The first phase of the project was the installation of the new signal processor. The second step was the renovation of the transmitter. The fourth step is the renovation of the equipment shelters.

The eight-year project, NEXRAD Service Life Extension Program (SLEP), is a $135 million program from the NWS, the United States Air Force and the Federal Aviation Administration that aims to extend the life of the WSR-88Ds into the 2030s. Completion of the project is scheduled for 2023.

“I think it’s two to four [dishes being renovated] across the country every few weeks until they are all replaced by the upgraded or refurbished systems,” said Gilmore, who has been with the NWS’s Little Rock branch since 2009.

Central Arkansas will not be without radar coverage during the two-week period that KLZK is off the air. Instead, the WSR-88Ds in Springfield, Mo. (KSGF); Millington, Tenn. (KNQA); Brandon, Ms. (KDGX); Shreveport, La. (KSHV) and in Fort Smith (KSRX) intervene.

It’s not an entirely unusual situation for the Little Rock NWS.

The radar has been taken offline due to lightning strikes, forcing Little Rock to rely on other radars.

“We also have other tools that we use, such as high-resolution satellite data that we can use to compensate,” Gilmore said. “We always have eyes out there. We won’t have our local radar for up to two weeks.” Even with the neighboring radars in place, there can be blind spots.

“The biggest thing we can run into is that as the radar beam goes over the land, the Earth curves,” Gilmore said. “As that happens, the radar beam gets higher and higher off the ground as you get further out. The farther you are from the radar, the higher in the atmosphere it sees. There is a possibility that we will not be able to see some near-ground features.” Cases like this are why the NWS uses its network of storm spotters.

The NWS’ human “eyes and ears on the ground” include local law enforcement, fire departments and volunteer storm spotters.

“We use those on a daily basis,” Gilmore said. “We always try to use everything we have at our disposal to accomplish our mission.”

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