SWPC warnings will transition to be based on an estimate or predictionof the Planetary indices Kp and Ap

From: SWPC Product Subscription Service

As announced on our website, effective November 16, 2011, the Space
Weather Prediction Center (SWPC) will be making numerous changes to its
geomagnetic product suite. SWPC's nowcast and forecast products, alerts,
watches, and warnings will transition to be based on an estimate or
prediction of the Planetary indices Kp and Ap. Currently all of these
products are based off of the K-index computed from the Boulder
magnetometer and the A-index from Fredericksburg, Virginia. The impact
of the change should be minimal and no changes to product subscriptions
will be required.

For more details on the change, please see the customer announcement on
our website at:

http://www.swpc.noaa.gov/geomag/geomag.html