Nuclear fallout and wind patterns

How will we know if a nuke is dropped which areas would have the least or most fallout? Exp if a bomb was dropped in Los Angeles, San Fran or San Diego how would that effect me where I live (San Fernando Valley)?

Does it change day to day or is there a bigger underlying wind pattern that is consistent?

Try this site.
www.webpal.org...

The information seems a little old but there is still some good stuff on this site. I like the fact that you can also check each state individually.