To accomplish this mission, the NWS gathers information from a variety of sources and uses that information to determine the potential hazard for any given area. Some of the sources of information are surface observations, balloon observations, severe weather spotters , law enforcement agencies, remote automatic sensors, radar and satellites . Severe Weather Tornadoes and severe thunderstorms are the most violent of all weather phenomena that occur in nature. Fortunately, these storms rarely occur in Northwest California. The threat from tornadoes is obvious and the threat from severe thunderstorms are varied.
Thunderstorms can produce deadly lightning, hail, heavy rain, violent winds.
During the dry season they can also produce forest fires. You should not rely on this source for you primary source of getting this information. Instead check our NOAA Weather Radio or a local media source. Today's Severe Outlook Map and Text Tomorrow's Severe Outlook Map and Text Significant or Winter Weather Non-severe, yet significant weather events are common across Northwest California. During the summer months, fog advisories are typical, while during the winter, Wind Advisories and Winter Storm Warnings are commonly issued.