To minimize potential flooding, SFPUC crews have been preparing in advance of the weekend storm by flushing the sewer lines and cleaning catch basins.
You can help too: before you go out and about shopping for the holidays, just sweep away leaves and debris away from catch basins.
In SF, to report clogged catch basins or street flooding, contact 311 or @sf311. You can also go to http://www.sf311.org/.
Stay dry and good luck shopping in the rain!