Southern California Weather Force has issued a Thunderstorm Watch effective now through the evening, effective for Big Bear, Wrightwood, Barstow to Fort Irwin, Ridgecrest, Las Vegas, Riverside County Mountains (Not on the map),  and Yucaipa to Cherry Valley.

A ridge similar to that of the monsoon will move into place today.  Instability is expected to develop further by this afternoon and evening, with the upper-level lifting zone moving into the region as well.  As this happens, rapid moisture influx will bring precipitation to the area.  The onshore flow combined with the offshore component will have storms developing in the Yucaipa/Cherry Valley area first and then the rest will follow this forecast.

In addition to the lightning, some hail, at times large, and strong winds will accompany the storm …