I know I've been away from home for a while but I know tornado weather when I see it.
If you're in a building with a basement get to it, but I don't think we have many here. Interior rooms, no windows, bathrooms or closets usually work well. Grab some pillows to cover your head, a mattress if you're able to move one around. Bike helmets are good, too.
Somehow I don't think San Francisco has tornado sirens. Keep a TV or radio on for warnings, the weather people are freaking out but I figure they can still manage that much.
Dads, I'm leaving school, if one of you can write me a note that'd be great. I don't know if they'll close or not, this obviously isn't normal here. Molly is leaving, too.