Sunspot region 2403, M-class solar flares

Friday, 21 August 2015 17:32 UTC

Moderately strong M1.23 solar #flare from #sunspot region 12403 - Follow live on http://t.co/XHATH0OOfT pic.twitter.com/2NetxQ7vz1

— SpaceWeatherLive (@_SpaceWeather_) 21 augustus 2015

Moderately strong M1.43 solar #flare from #sunspot region 12403 - Follow live on http://t.co/XHATH0OOfT pic.twitter.com/QYTWpVwkAe

— SpaceWeatherLive (@_SpaceWeather_) 21 augustus 2015

The first of these M-class events (M1.2) did not launch a coronal mass ejection. The second M-class solar flare was associated with both Type II and Type IV radio sweeps and peaked at the M1.4 class. This event did launch a coronal mass ejection which we can classify as a partial halo coronal mass ejection that extends more than 180 degrees around the C2 coronagraph. The bulk of this coronal mass ejection is heading southward but a very faint northward extension can be seen if you look very closely meaning that a small part of this plasma cloud could very well be directed towards our planet. There is however also some bad news: we have to conclude that this coronal mass ejection is rather weak (faint halo) and very slow meaning we do not think it wil leave a notable trace in the solar wind here at Earth. A significant geomagnetic distrubance from this plasma cloud is unlikely.

Image: SOHO/LASCO C2 animation showing the coronal mass ejection launched by the M1.4 solar flare.

ALERT: Type II Radio Emission
Begin Time: 2015 Aug 21 0959 UTC
Estimated Velocity: 490 km/s

ALERT: Type IV Radio Emission
Begin Time: 2015 Aug 21 0942 UTC

It is not just bad news as high latitude sky watchers will have a chance to catch aurora this weekend: we did had a coronal hole facing Earth the past few days and expect a solar wind stream from this coronal hole to cause enhanced geomagnetic conditions in the coming days.

Image: The Sun right now in the 211 Angstrom wavelength as seen by SDO. Coronal holes show up as black areas on this image.

M-class flare probability for the coming 24 hours: 55% chance
X-class flare probability for the coming 24 hours: 5% chance

Images: Sunspot region 2403 as seen by SDO's HMI instrument.