The below link will take you to NOAA's server to access their shape files. If you have a program that reads these files, it's an excellent way to get more information through your website. IE StormLab.
http://www.hpc.ncep.noaa.gov/html/about_gis.shtmlYou can either use an FTP download program to pull the files from their server or directly download through Internet explorer. For shape files, make sure you download .dbf, .shx, and .shp.
They also have KML files for use with Google Earth.
I already added the Significant Flood Outlook to StormLab and it's a nice addition.