From the Rice University Spaceweather listserver:
The listserver moderator writes in a separate email:
WOW – a real honest substorm coming!
As those in our “spacalrt” email listserver have just heard, the ACE spacecraft is measuring a high speed southward IMF, so the the Boyle Index (BI) went above 200 for the first time in a number of years! If this level of solar wind continues (it is falling slowly), there will be geomagnetic activity with Kp of 5 or more in the next three hours, according to our neural net predictions. Depending on how sustained the solar wind is, the prediction may go above 6… stay tuned!! At the very least this may be the best event of the new solar cycle… whew!
Unfortunately for skywatchers in the western hemisphere, we will be in daylight, but European and Asian colleagues should be on the lookout for auroras in the next few hours.
To watch the BI and our real-time 3 and 1-hour ahead Kp predictions, go to
(it also shows the “realtime” Kp estimates in red, which arrive well after our predictions for that time interval).
The Boyle index (BI) gives the value of the “asymptotic polar cap potential” – i.e. the value that the electric potential across the ionospheric flow WOULD get to if the solar wind is steady for 4 hours. It does NOT include a saturation term, so it will overestimate the true potential for major storms. However, since certain measures of geomagnetic activity don’t saturated, a
BI of 300 does imply a stronger storm than a BI of 200, even though the actual polar cap potential may turn out to be about the same because of saturation.
For those not yet on our “spacalrt” email warning system, you can get free email warnings by sending an email to:
Unrelated to Rice U, but also of interest, is the recent plot of TSI (Total Solar Irradiance) by the SORCE spacecraft. – Anthony