There is a 50% chance of polar geomagnetic storms on September 17, 2014, as another CME is en route to Earth.
The icoming CME was triggered by the eruption of a magnetic filament near the center of the solar disk four days ago .
You can watch in the original movie from the Solar and Heliospheric Observatory that the Earth-directed CME is almost overwhelmed, visually, by a brighter farside CME headed in the opposite direction.
The impact will not be as intense as the double-blow Earth experienced on September 12, 2014. But NOAA estimates a 50% chance of polar geomagnetic storms on September 17, 2014.
So high-latitude sky watchers, prepare yourself for dancing and swirling auroras!