Press Releases

Feinstein Announces Weather Radar Upgrade in San Joaquin Valley

New technology will improve local weather forecasts and warnings

Washington—Senator Dianne Feinstein (D-Calif.) today announced that the National Weather Service’s San Joaquin Valley Forecast Office has upgraded the Doppler radar that serves Central California with new, life-saving technology.

The new radar technology—called dual polarization, or “dual pol”—gives meteorologists enhanced information about the atmosphere so they can more accurately track, assess and warn the public of approaching weather.

“The new radar technology will help the National Weather Service keep a sharper eye on the sky, leading to better forecasts and warnings for Central California residents,” said Senator Feinstein. “This new radar technology will also help forecasters make better decisions about when to issue warning for flash floods, which in an average year cause more damage and deaths than any other kind of severe weather event.”

The San Joaquin Valley Forecast Office serves nearly 3 million people in Kern, Kings, Fresno, Mariposa, Madera, Merced and Tulare counties, as well as California’s Yosemite National Park.

The upgrade to dual-pol is the most significant enhancement ever made to the nation’s NEXRAD radar network since Doppler radar was first installed in the early 1990s. The upgrade includes new software and a hardware attachment to the radar dish allowing it to send and receive both horizontal and vertical pulses, providing a much more informative, two-dimensional picture of the size and shape of the objects detected. This provides meteorologists with the ability to determine the kind of object, whether rain, snow, hail or birds. Conventional Doppler only provides information about the intensity of precipitation.

“Using dual-pol, forecasters will have improved information about the amount of snow in storms moving across central California,” said Steven Mendenhall, meteorologist-in-charge, San Joaquin Valley forecast office. “For instance, the radar will help us pinpoint where rain turns to snow, sleet or freezing rain which can mean the difference between normal traffic flow and zero traffic flow on Interstate 5 between the Valley and Los Angeles - a route traveled by thousands of vehicles each hour. Fine-tuned winter weather forecasts will be beneficial to state and local emergency managers as well as motorists.”

Businesses in the region will also benefit from the enhanced information dual-pol brings. The multi-billion dollar San Joaquin Valley agriculture industry, utility companies, airlines, visitors to national parks/Sierra Nevada, several military installations and other federal government agencies, and others who rely on weather forecasts will have a clearer picture of current weather conditions and better information to protect their lives and livelihoods.

The nationwide upgrade to dual-pol is part of NOAA’s efforts to build a Weather-Ready Nation. Dual-pol radars also could save the nation about $700 million annually by reducing weather-related damages. NOAA has posted an online video with more about the new weather radar.

Media inquiries can be directed to Steven Mendenhall, meteorologist-in-charge at the San Joaquin Valley Forecast Office. He can be reached at 559-584-0583 or