Weak CME could give us a glancing blow

Thursday, 29 June 2017 23:13 UTC

Minor coronal dimming was observed yesterday afternoon near sunspot region 2664 which could be an indicator that some solar plasma was ejected into space. The eruption was related to a long duration B1 solar flare at the same time. Coronagraph imagery from SOHO/LASCO shows us a slow partial halo coronal mass ejection as you can see in the animation below.

⇧ The coronal mass ejection as captured by the SOHO/LASCO C2 coronagraph.

The plasma cloud is slow (at most 300km/s) and can be seen as a partial halo structure that reaches almost 180 degrees as seen on these SOHO/LASCO C2 images which sees the expanding plasma cloud from earth's point of view. Note that there is a second coronal mass ejection heading towards the east. This is from an unrelated event and should be ignored.

Our conclusion is that this plasma cloud could arrive as a glancing blow at Earth on July 2nd or 3rd due to the relatively favourable earth-directed position of the eruption and the near 180 degrees partial halo outline. Geomagnetic storming is not expected as the plasma cloud is too slow and likely will not impact us head on but it could be an interesting event to keep an eye on for high latitude sky watchers that aren't plagued by the midnight sun.