Special Weather Statement issued May 29 at 3:18PM PDT until May 31 at 12:00AM PDT by NWS

...SPECIAL WEATHER STATEMENT... At 318 PM PDT, Doppler radar was tracking a strong thunderstorm over Kyburz, or 12 miles northwest of Kirkwood. This storm was nearly stationary. Half inch hail and winds in excess of 30 mph will be possible with this storm.

from Current Watches, Warnings and Advisories for the United States Issued by the National Weather Service http://ift.tt/2rdAyKQ