G2 – Moderate geomagnetic storm in progress

After strong G3 geomagnetic storm on March 6 and 7, solar wind parameters increased again around 04:00 UTC on March 11. 

The cause is most likely a Coronal Mass Ejection (CME) from March 6. Interplanetary magnetic field (IMF) total field (Bt) valuese steadly increased from 4 to 26 nT after 04:00 UTC. 

Geomagnetic K-index of 5 (G1 – Minor geomagnetic storm) threshold was reached at 13:00 UTC. At 14:41 UTC, geomagnetic storming increased to G2 – Moderate levels.

Due to continued CME effects, solar wind parameters are expected to remain enhaced on March 11 and 12 and then followed by the onset of a positive polarity coronal hole high speed stream (CH HSS).

Image credit: NOAA/SWPC

Meanwhile, solar activity is very low and only background flaring is being observed.

SWPC alerts

Space Weather Message Code: ALTK06
Serial Number: 398
Issue Time: 2016 Mar 11 1441 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2016 Mar 11 1441 UTC
Synoptic Period: 1200-1500 UTC

Active Warning: Yes
NOAA Scale: G2 – Moderate

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

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents – Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft – Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio – HF (high frequency) radio propagation can fade at higher latitudes.
Aurora – Aurora may be seen as low as New York to Wisconsin to Washington state.

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Space Weather Message Code: ALTK05
Serial Number: 939
Issue Time: 2016 Mar 11 1301 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2016 Mar 11 1300 UTC
Synoptic Period: 1200-1500 UTC

Active Warning: Yes
NOAA Scale: G1 – Minor

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 credit: Sacha Layos. Captured on March 11, 2016 at Fairbanks, Alaska. Via SpaceWeather.com