G1 – Minor geomagnetic storm in progress

A negative polarity, southern crown coronal hole extension has moved into a geoeffective position enhancing the solar wind environment. Unsettled levels are expected on April 21 as high speed stream (HSS) effects persist. By late April 22 (UTC), a positive polarity coronal hole high speed stream (CH HSS) is expected to become geoeffective causing quiet to unsettled conditions.

Geomagnetic K-index of 4 threshold was reached at 08:57 UTC on April 20, followed by K-index of 5 (G1 – Minor geomagnetic storm) at 10:44 UTC.

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Space Weather Message Code: ALTK04
Serial Number: 2154
Issue Time: 2020 Apr 20 0857 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2020 Apr 20 0855 UTC
Synoptic Period: 0600-0900 UTC

Active Warning: Yes

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

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents – Weak power grid fluctuations can occur.
Aurora – Aurora may be visible at high latitudes such as Canada and Alaska.

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Space Weather Message Code: ALTK05
Serial Number: 1293
Issue Time: 2020 Apr 20 1045 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2020 Apr 20 1044 UTC
Synoptic Period: 0900-1200 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.

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Featured image credit: NOAA/SWPC