At approximately 8:55 UT a large filament on the northwest of the sun erupted and at nearly the same time in sunspot active region 11902, a C3 flare occurred. In addition to the flare, a coronal wave can be seen coming from the sunspot group. Nearly 10 hours later another filament, southeast of the first filament, also erupted.
Two CMEs were produced from this set of events and should impact the earth on Aug 4th and 5th. These may produce some aurora and solar storms but the effect is predicted to be minimal. In as far as we can tell at this time these CMEs are not fast or otherwise extraordinary.
The flare and the first filament eruption seem to occur together in what scientists often refer to as a “sympathetic” event – a set of events where one event appears to have caused the other event. So the big question is, “Which came first, the flare or the filament eruption?” This difficult yet important question is precisely one of the reasons the Solar Dynamics Observatory was built to answer.
This video produced at the Lockheed Martin Solar Astrophysics Lab is a composite of 3 different wavelength images from the Solar Dynamics Observatory (SDO). This mostly shows the hot corona but some darker chromospheric material (filament) can be seen.