There is some discussion of the prediction methods under the discussion forum found at the page I mentioned last night: http://www.spacew.com/www/aurora.html If you page past the "oh wow" messages you'll find a couple of experts on line pretty much continuously with good explanations of the various indices and predictors. The arrival of the big events can be anticipated by events on the Sun itself (obviously) but also there's a spacecraft stationed upstream that takes some relevant measurements that gives warnings on the order of an hour ahead. Someone like Jeff Medkeff or Rik Hill can provide some additional on-line info links. \Brian --- This message is from the AZ-Observing mailing list. If you wish to be removed from this list, send E-mail to: AZ-Observing-request@xxxxxxxxxxxxx, with the subject: unsubscribe. The list's archive is at: //www.freelists.org/archives/az-observing This is a discussion list. Please send personal inquiries directly to the message author. In other words, do not use "reply" for personal messages. Thanks.