Tuesday, 17 March 2015

Space Weather Alert: Geomagnetic K-index of 8 (G4)

Image: Aurora Australis captured only moments ago by Eddie Griffiths from New Zealand.
 Image: OVATION model run for the northern hemisphere valid at 2015-03-17 09:15 UTC.

The coronal mass ejection likely associated with the C9 solar flare has arrived at Earth, much earlier than expected. A sudden increase in the solar wind and IMF parameters were observed but the direction of the IMF stayed north until around 06:00 UTC when it turned southward for a couple of hours to about -20nT. The geomagnetic field responded and a moderate G2 geomagnetic storm followed.

Current conditions

Coronal mass ejection effects continue at the time of writing with the solar wind speed being close to 600km/s and the strength of the IMF being close to a high value of 25nT. The direction of the IMF is however pointing north now around 12nT which should cause the geomagnetic conditions to calm down a bit in the hours ahead. Nonetheless, the geomagnetic field is disturbed and more auroral outbreaks are possible. Sky watchers in Tasmania and Victoria (Australia) and the southern island of New Zealand along with the upper United States should remain alert for aurora providing skies are clear at your location.
It is still too early to tell what European sky watchers should expect but CME effects will likely persist for another 12 to 24 hours. The direction of the IMF could very well turn southward in the hours ahead which could spark more aurora over Europe this coming evening. Keep an eye on the stats as European evening hours approach.