X9.3 CME impact, Severe G4 storm

Friday, 8 September 2017 03:37 UTC

X9.3 CME impact, Severe G4 storm

The X9.3 coronal mass ejection has arrived at Earth and boy does it pack a punch! While the M5.5 coronal mass ejection turned out to be a huge dissapointment, the X9.3 coronal mass ejection is much stronger than expected and we are seeing some of the strongest geomagnetic storming of the current solar cycle.

The plasma cloud was fashionably early actually, something we do not see so often. It passed DSCOVR already yesterday (7 september) at 22:29 UTC which is 7,5 hours earlier than our prediction and almost a full day earlier than NOAA's prediction.

The total interplanetary magnetic field strength (Bt) increased to 26nT at impact with a further increase slightly later peaking out at exactly 34nT at 22:58 UTC. The north-south component of the IMF (Bz) reached a maximum southward value of -32.9 nT at 22:57 UTC. Solar wind speeds increased from about 500 to almost 700km/s. Our automated coronal mass ejection impact system detected the shock wave as it passed DSCOVR and was of course on duty to report the event.

These conditions quickly sparked a severe G4 geomagnetic storm which means middle latitude sky watchers have a real chance to see aurora!

Any mentioned solar flare in this article has a scaling factor applied by the Space Weather Prediction Center (SWPC), the reported solar flares are 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.

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