Updated

The National Weather Service has issued a tornado warning for parts of Southern California as the region is being pounded by wild weather including torrential downpours.

The weather service said at 4:38 p.m. Thursday that Doppler radar was tracking a tornado moving south near Moreno Valley in Riverside County.

A KABC-TV helicopter in the area has shown an overturned big rig blocking a highway and a half-dozen freight cars toppled over on nearby railroad tracks.

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