San Mateo County Deploys 6-Radar Network Ahead of El Niño Storms

San Mateo County emergency officials are deploying a localized 6-radar weather monitoring network ahead of winter storms fueled by El Niño conditions, king tides, and warming coastal waters, according to Dustin Dorsey at ABC7 News.

Scanning Low-Altitude Atmospheric Rivers Below Standard Radar Beams

Developed by the Center for Western Weather and Water Extremes at the Scripps Institution of Oceanography at UC San Diego, the 6 new regional radars supplement National Weather Service data after a recent high-tide event inundated a San Mateo County park within minutes.

Dr. F. Martin Ralph, director of the Center for Western Weather and Water Extremes, explained that when atmospheric rivers cross warm coastal waters, the ocean adds heat and moisture to the air that fuels heavier precipitation.

Ryan Reynolds, assistant director for the San Mateo County Department of Emergency Management, noted that most atmospheric river systems travel very low — within a few thousand feet of the surface — where large National Weather Service radars tend to shoot over the top of them. By scanning those lower elevations directly, the 6-radar network can give emergency managers up to 1 hour of advance notice to send localized flood alerts to at-risk Peninsula neighborhoods. At the federal level, U.S. Rep. Kevin Mullin has also introduced legislation to strengthen localized safety alerts ahead of major storms.