Space Weather Message Code: ALTK06 Serial Number: 514 Issue Time: 2023 Mar 23 1946 UTC ALERT: Geomagnetic K-index of 6 Threshold Reached: 2023 Mar 23 1942 UTC Synoptic Period: 1800-2100 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: 1444 Issue Time: 2023 Mar 23 1725 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2023 Mar 23 1722 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: 125 Issue Time: 2023 Mar 23 1531 UTC ALERT: Geomagnetic K-index of 7 Threshold Reached: 2023 Mar 23 1449 UTC Synoptic Period: 1500-1800 UTC Active Warning: Yes NOAA Scale: G3 – Strong Comment: This alert is a correction. G3 conditions were first observed at 1449 UTC and not 1446 UTC as previously alerted on 23 Mar 2023 at 1450 UTC. This alert supercedes

Space Weather Message Code: ALTK07 Serial Number: 124 Issue Time: 2023 Mar 23 1450 UTC ALERT: Geomagnetic K-index of 7 Threshold Reached: 2023 Mar 23 1446 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: WARK07 Serial Number: 88 Issue Time: 2023 Mar 23 1447 UTC WARNING: Geomagnetic K-index of 7 or greater expected Valid From: 2023 Mar 23 1447 UTC Valid To: 2023 Mar 23 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: 513 Issue Time: 2023 Mar 23 1426 UTC ALERT: Geomagnetic K-index of 6 Threshold Reached: 2023 Mar 23 1423 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: WARK05 Serial Number: 1757 Issue Time: 2023 Mar 23 1421 UTC EXTENDED WARNING: Geomagnetic K-index of 5 expected Extension to Serial Number: 1756 Valid From: 2023 Mar 23 0905 UTC Now Valid Until: 2023 Mar 24 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 60 degrees Geomagnetic Latitude. Induced Currents –

Space Weather Message Code: WARK06 Serial Number: 475 Issue Time: 2023 Mar 23 1420 UTC WARNING: Geomagnetic K-Index of 6 expected Valid From: 2023 Mar 23 1420 UTC Valid To: 2023 Mar 23 2100 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

Space Weather Message Code: ALTK05 Serial Number: 1443 Issue Time: 2023 Mar 23 1236 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2023 Mar 23 1234 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: WARK05 Serial Number: 1756 Issue Time: 2023 Mar 23 0905 UTC WARNING: Geomagnetic K-index of 5 expected Valid From: 2023 Mar 23 0905 UTC Valid To: 2023 Mar 23 1500 UTC Warning Condition: Onset 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