Since the local surfers seem to be tuned into the N. Swell conditions and predictions I find that their sites are often the most accurate and informative. This site has some other USVI and BVI locations available on a drop down menu and a good amount of down island info as well.Since I look down at one of the USVI locations posted I know from personal experience the forecast is fairly accurate on size and close on timing.

http://www.swellinfo.com/surf-forecast/tortola <img src="http://www.traveltalkonline.com/forums/images/graemlins/titanic.gif" alt="" />