From a coronal hole high speed stream/ plasma density increase: Space Weather Message Code: ALTK04 Serial Number: 2257 Issue Time: 2021 Dec 27 1258 UTC ALERT: Geomagnetic K-index of 4 Threshold Reached: 2021 Dec 27 1257 UTC Synoptic Period: 1200-1500 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.
