Southern crown coronal hole stirring up geomagnetic storms

Earth is currently under the influence of a high speed solar wind speed, originating in negative polarity southern crown coronal hole, which is causing periods of geomagnetic storming on our planet.

Solar wind readings indicated a co-rotating interaction region (CIR) which came in advance of a negative polarity southern crown coronal hole high speed stream (CH HSS) yesterday. Enhanced density readings along with a rise in total field was followed by increased Bz variability.

Wind speed gradually increased from near 400 km/s to about 550 km/s through 18:15 UTC on February 1 when wind speeds sharply increased to a peak of 748 km/s at 20:06 UTC. 

Afterwards, wind speed averaged close to 675 km/s.

Wind speed increased again, from near 540 km/s to a maximum of 783 km/s at 05:46 UTC on February 2 before leveling off near 660 km/s.  Total field increased to a maximum of 15 nT by 01:38 UTC, but dropped to around 6 nT after 04:26 UTC. The Bz component was variable between +10 nT and -12 nT during last 12 hours.

Solar wind parameters are expected to continue to be enhanced under CH HSS influence for the next three days (February 2 – 4). 

The geomagnetic field was at quiet to minor storm (G1-Minor) levels due to aforementioned CIR and CH HSS effects during last 24 hours. Minor storming periods were observed from 21:00 UTC yesterday until 06:00 UTC today.

Unsettled to minor storm (G1) levels are expected to continue today due to CH HSS activity. Quiet to active conditions are expected by February 3 and 4.

Space Weather Message Code: WARK05
Serial Number: 961
Issue Time: 2015 Feb 02 1227 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 960
Valid From: 2015 Feb 01 2105 UTC
Now Valid Until: 2015 Feb 03 0000 UTC
Warning Condition: Persistence

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

Featured image: Aurora over Reykjavik. Taken by Magnus (ReykjavikPhoto.com) on February 2, 2015 @ Reykjavik, Iceland (via SpaceWeather.com)