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CME impact sparks geomagnetic storms reaching G2 moderate levels

cme-impact-sparks-geomagnetic-storms-reaching-g2-moderate-levels

Coronal Mass Ejection (CME) unleashed by a long duration M3.7 solar flare on November 4 reached our planet at 18:25 UTC on November 6, almost a full day earlier than it was expected. An enhanced magnetic field, coupled with winds speeds approaching 700 km/s have produced G1 – G2 (Minor – Moderate) geomagnetic storms at Earth.

Solar wind parameters were steady at background levels until 17:35 UTC when the interplanetary shock wave impacted ACE spacecraft. Solar wind speeds increased from 440 km/s to over 600 km/s and total field strength values increased from 5 nT to 19 nT. Bz briefly reached -13 nT shortly after shock passage but was mostly northward, according to SWPC.

Solar wind parameters are expected to remain enhanced over the next three days (November 7 – 9) due to continued CME effects early in the period followed by the onset of a positive polarity coronal hole high speed stream (CH HSS) later in the period.

Geomagnetic K-index of 5 (G1 – Minor geomagnetic storm) threshold was reached at 02:59 UTC on November 7. Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.

Under G1 conditions, weak power grid fluctuations can occur. Minor impact on satellite operations is possible. Aurora may be visible at high latitudes.

Geomagnetic K-index of 6 (G2 – Moderate geomagnetic storm) threshold was first reached at 04:11 UTC and then at 07:31 UTC. Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.

Under G2 conditions, power grid fluctuations can occur. High-latitude power systems may experience voltage alarms. Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible. HF (high frequency) radio propagation can fade at higher latitudes. Aurora may be seen as low as New York to Wisconsin to Washington state.

G1 -Minor geomagnetic storms are likely on November 8 due to the onset of positive polarity CH HSS influence. Unsettled to active field conditions are expected on November 9 due to weakening CH HSS influence.

SWPC alerts

Space Weather Message Code: ALTK05
Serial Number: 884
Issue Time: 2015 Nov 07 0301 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2015 Nov 07 0259 UTC
Synoptic Period: 0000-0300 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.

***

Space Weather Message Code: ALTK06
Serial Number: 381
Issue Time: 2015 Nov 07 0417 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2015 Nov 07 0411 UTC
Synoptic Period: 0300-0600 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.

***

Space Weather Message Code: ALTK06
Serial Number: 382
Issue Time: 2015 Nov 07 0740 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2015 Nov 07 0731 UTC
Synoptic Period: 0600-0900 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.

Featured image: Aurora forecast at 07:20 UTC on November 7, 2015. Image credit: SWPC

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