Geomagnetic storm in progress, CH HSS influence expected until October 27

Earth is passing through a stream of high speed solar wind produced by a recurrent, polar connected, positive polarity coronal hole. This is causing isolated periods of G1 class geomagnetic storming. G2 – Moderate geomagnetic storm watch is in effect for October 25 and 26.

At 09:00 UTC today, solar wind speeds were around 430 km/s but are expected to reach around 700 km/s today.

Geomagnetic K-index of 5 (G1 Minor geomagnetic storming) threshold was reached at 05:59 UTC today. Area of impact was primarily poleward of 60 degrees Geomagnetic Latitude. Under G1 conditions, weak power grid fluctuations can occur, minor impact on satellite operations is possible and aurora may be visible at high latitudes.

A G2 Moderate geomagnetic storm watch is in effect for October 25 and 26. G2 storm impact is 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 and increased drag on low Earth-orbit satellites is possible. HF (high frequency) radio propagation can fade at higher latitudes and aurora may be seen as low as New York to Wisconsin to Washington state.

This episode of increased geomagnetic activity is expected to last at least until October 27.

Space weather overview. Credit: SWPC

Meanwhile, solar activity is very low. No solar flares were observed yesterday and there is just a chance for C-class flaring over the next three days.

There is only one numbered sunspot region on the Earth side of the Sun, Region 2603 (Beta).

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Space Weather Message Code: WATA30
Serial Number: 148
Issue Time: 2016 Oct 24 2112 UTC

WATCH: Geomagnetic Storm Category G2 Predicted

Highest Storm Level Predicted by Day:
Oct 25:  G2 (Moderate)   Oct 26:  G2 (Moderate)   Oct 27:  G1 (Minor)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

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: 1032
Issue Time: 2016 Oct 25 0601 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2016 Oct 25 0559 UTC
Synoptic Period: 0300-0600 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: Coronal hole as seen by NASA’s SDO on October 23, 2016.