Space Weather Message Code: WARK04 Serial Number: 3899 Issue Time: 2021 May 13 0531 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 3898 Valid From: 2021 May 12 0600 UTC Now Valid Until: 2021 May 13 1500 UTC Warning Condition: Persistence 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 –

Space Weather Message Code: WARK04 Serial Number: 3898 Issue Time: 2021 May 12 1759 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 3897 Valid From: 2021 May 12 0600 UTC Now Valid Until: 2021 May 13 0600 UTC Warning Condition: Persistence 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 –

Space Weather Message Code: ALTK06 Serial Number: 480 Issue Time: 2021 May 12 1542 UTC ALERT: Geomagnetic K-index of 6 Threshold Reached: 2021 May 12 1542 UTC Synoptic Period: 1500-1800 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

Space Weather Message Code: ALTK05 Serial Number: 1331 Issue Time: 2021 May 12 1529 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2021 May 12 1528 UTC Synoptic Period: 1500-1800 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.

Space Weather Message Code: ALTK07 Serial Number: 115 Issue Time: 2021 May 12 1259 UTC ALERT: Geomagnetic K-index of 7 Threshold Reached: 2021 May 12 1258 UTC Synoptic Period: 1200-1500 UTC Active Warning: Yes NOAA Scale: G3 – Strong NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic Latitude. Induced Currents – Power system voltage irregularities possible, false

Space Weather Message Code: WARK05 Serial Number: 1600 Issue Time: 2021 May 12 1252 UTC EXTENDED WARNING: Geomagnetic K-index of 5 expected Extension to Serial Number: 1599 Valid From: 2021 May 12 0700 UTC Now Valid Until: 2021 May 12 1800 UTC Warning Condition: Persistence 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 –

Space Weather Message Code: WARK07 Serial Number: 77 Issue Time: 2021 May 12 1249 UTC WARNING: Geomagnetic K-index of 7 or greater expected Valid From: 2021 May 12 1250 UTC Valid To: 2021 May 12 1800 UTC Warning Condition: Onset NOAA Scale: G3 or greater – Strong to Extreme NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic

Space Weather Message Code: ALTK06 Serial Number: 479 Issue Time: 2021 May 12 1232 UTC ALERT: Geomagnetic K-index of 6 Threshold Reached: 2021 May 12 1232 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

Space Weather Message Code: ALTK05 Serial Number: 1330 Issue Time: 2021 May 12 1230 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2021 May 12 1230 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.

Space Weather Message Code: WARK06 Serial Number: 443 Issue Time: 2021 May 12 1228 UTC WARNING: Geomagnetic K-Index of 6 expected Valid From: 2021 May 12 1225 UTC Valid To: 2021 May 12 1800 UTC Warning Condition: Onset 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