G2 geomagnetic storm, northern Bz, coronal hole

Tuesday, 8 September 2015 18:33 UTC

Header image: Marcel de Bont (Skellefteå, Sweden)

Image: Marcel de Bont (Skellefteå, Sweden)

Image: Ve Or‎ (Wiefels, Germany)

Image: Christian Hering-Junghans‎ (Alberta, Canada)

Image: Travis Novitsky (Grand Portage State Forest, MN, USA)

Image: Mark Ferrier (Scotland)

Image: Beate Behnke (Northern Sweden)

Image: Yvonne Johannesström (Northern Sweden)

Image: Jüri Voit (Estonia)

Image: Kris Williams (Anglesey, UK)

Current conditions

The direction of the IMF (Bz) has now shifted to a northward direction, which plummeted us back to quiet geomagnetic conditions. We think this shift to a constant northward Bz might be from a weak coronal mass ejection associated with a filament eruption. Geomagnetic conditions are expected to be quiet (Kp2 or less) in the coming hours unless the Bz shifts southward again but this is unlikely.

UPDATE 00:29 UTC: The direction of the IMF (Bz) has finally shifted southwards and European magnetometers are already responding. The NOAA SWPC reported a Kp of 4 already which stands for active geomagnetic conditions. If the Bz continues to point southwards then sky watchers in northern Scotland and around the US-Canadian border should be alert for aurora near the horizon.

What can we expect the coming days

More aurora is possible in a few days as we have yet again a coronal hole in an earth-facing position. Solar wind flowing from this coronal hole could arrive on Friday and a minor G1 geomagnetic storm can be expected.

Image: A coronal hole is now facing Earth as can be seen on this image from SDO.