The National Weather Service radar system on Mount Ashland will be down for five days this week for system upgrades.

Technicians began installing a new signal processor on the WSR-88D radar dish today, which will improve processing speed and data quality, Weather Service officials reported.

Radar coverage will be available from adjacent radar sites in Eureka, Sacramento, Portland, Pendleton and Reno, but local coverage will be impacted.

"That’s why it’s good we’re not expecting a big outbreak of thunderstorms this week," said meteorologist Ryan Sandler. "That would have been bad news."

The work is part of a four-phase, $150 million project spanning five years, intended to extend the life of the  20-year-old dish and 121 other Next Generation Weather Radar — NEXRAD — facilities across the U.S. into the 2030s. The service-life extension program includes major component replacements on the dishes, including the signal processors, transmitters, pedestals and equipment shelters.

The National Weather Service, U.S. Air Force and Federal Aviation Administration all use the technology.

The Medford NEXRAD system went live in April 1996. The 28-foot dish beneath a white fiberglass globe on Mount Ashland sends out pulses of electromagnetic energy and can gather data from storm clouds that include the intensity and size of rain and hail, air circulation and wind speed.

From 1971 to 1995, the agency used WSR-57, or Weather Surveillance Radar 1957, named for the year the technology was built.

— Reach reporter Ryan Pfeil at 541-776-4468 or rpfeil@mailtribune.com. Follow him at www.twitter.com/ryanpfeil.