Source - Space Weather News for Sept. 9. 2011: http://spaceweather.com
GEOMAGNETIC STORM: A strong geomagnetic storm (Kp=7) is in progress following the impact of a CME during the middle hours of the day on Sept. 9th. This could be the first of several hits from a series of CMEs expected to reach Earth during the weekend. High-latitude sky watchers should be alert for auroras after nightfall. (Observing tip: The hours around midnight are often best for aurora sightings.) Check http://spaceweather.com for more information and updates.
SPACE WEATHER ALERTS: Would you like a call when geomagnetic storms are in progress? Storm alerts are available from http://spaceweathertext.com (text) and http://spaceweatherphone.com (voice).