Kite Wind Surf has a live weather station (the cam has been down for a while). Here's the link for them: http://www.kitewindsurf.com/store/windcam.aspx
Also, iKite has a few free wind charts in the Alameda area. One is at the Oakland airport and the other is at the Alameda Ports. Here are those links respectively:http://www.ikitesurf.com/windandwhere.i ... siteID=338http://www.ikitesurf.com/windandwhere.i ... siteID=337
For wind forecasts, I've found windguru to be pretty good.http://www.windguru.cz/int/index.php?sc=75401
As for a good wind range for a 12m, it really depends on a number of things (your skill, weight, etc.) but I would say 15-20 mph would be ideal.
Hope this helps.