A powerful storm dropping drenching rain on flood-prone Southern California is raising concern among forecasters that it could produce a dangerous, widespread outbreak of tornadoes, damaging winds and fires along with a blizzard as it crosses the entire United States in the coming days.

A colossal storm is threatening to bring severe weather to much of California this week and could impact travel over the Grapevine. Here's what to know.

A sweeping storm system moving across the U.S. threatens to bring tornadoes, blizzards and possibly wildfires to different regions of the country

On Sunday at 2:43 p.m. the NWS Medford OR released an updated winter storm warning in effect until Monday at 5 a.m. The warning is for Western Siskiyou County, South Central Siskiyou County and North Central and Southeast Siskiyou County.

Monday morning commuters woke up to a soggy start to their day in Northern California as the region is set to receive another round of rain and snow. The KCRA 3 weather team issued an Impact Day on Monday because rain and snow are expected to affect travel and outdoor activities.