THE FIRST CME HAS ARRIVED: The first of six CMEs hurled toward Earth by giant sunspot AR3664 just hit Earth's magnetic field. This could be a 'Cannibal CME' composed of two or three individual storm clouds--or simply the first of six. Either way, it looks like a big hit, setting the stage for NOAA's predicted severe (G4-class) geomagnetic storm.

UPDATE--SIX CMEs HURLED TOWARD EARTH: The number of CMEs heading for Earth keeps increasing. The total is now six following this morning's X3.9-class flare from giant sunspot AR3664. All six storm clouds are captured in this time-lapse movie from the Solar and Heliospheric Observatory (SOHO)
The two bright objects are Jupiter (left) and Venus (right). The CMEs will miss those planets and hit Earth instead.

According to a NOAA forecast model, the first three CMEs could merge to form a "Cannibal CME." Cannibal CMEs form when fast-moving CMEs overtake and gobble up slower CMEs in front of them. Internal shock waves created by such CME collisions do an good job sparking geomagnetic storms when they strike Earth's magnetic field.