The same storm that’s expected to dump 1 inch of rain on San Francisco later this week is going to really let loose in Northwestern California. Over 19 inches of rain could fill empty river and stream beds and head toward the Shasta, Whiskeytown and Trinity reservoirs, which need the water. Jan Null, a meteorologist with Golden Gate Weather Services, says this moisture is a result of the Pacific storm Typhoon Songda. He says while this amount of rain is unusual for October, it’s really not that unusual for that part of California.