Space Weather Message Code: ALTK07 Serial Number: 127 Issue Time: 2023 Mar 24 0157 UTC ALERT: Geomagnetic K-index of 7 Threshold Reached: 2023 Mar 24 0155 UTC Synoptic Period: 0000-0300 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: ALTK06 Serial Number: 516 Issue Time: 2023 Mar 24 0027 UTC ALERT: Geomagnetic K-index of 6 Threshold Reached: 2023 Mar 24 0025 UTC Synoptic Period: 0000-0300 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: 1446 Issue Time: 2023 Mar 24 0015 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2023 Mar 24 0014 UTC Synoptic Period: 0000-0300 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: 126 Issue Time: 2023 Mar 23 2355 UTC ALERT: Geomagnetic K-index of 7 Threshold Reached: 2023 Mar 23 2354 UTC Synoptic Period: 2100-2400 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: 89 Issue Time: 2023 Mar 23 2251 UTC WARNING: Geomagnetic K-index of 7 or greater expected Valid From: 2023 Mar 23 2250 UTC Valid To: 2023 Mar 24 0300 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: 515 Issue Time: 2023 Mar 23 2148 UTC ALERT: Geomagnetic K-index of 6 Threshold Reached: 2023 Mar 23 2146 UTC Synoptic Period: 2100-2400 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: 1445 Issue Time: 2023 Mar 23 2136 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2023 Mar 23 2133 UTC Synoptic Period: 2100-2400 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: WATA20 Serial Number: 940 Issue Time: 2023 Mar 23 2122 UTC WATCH: Geomagnetic Storm Category G1 Predicted Highest Storm Level Predicted by Day: Mar 24: G2 (Moderate) Mar 25: G1 (Minor) Mar 26: 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 60 degrees Geomagnetic Latitude. Induced Currents

Space Weather Message Code: WARK04 Serial Number: 4322 Issue Time: 2023 Mar 23 2006 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 4321 Valid From: 2023 Mar 23 0827 UTC Now Valid Until: 2023 Mar 24 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: WARK06 Serial Number: 476 Issue Time: 2023 Mar 23 1950 UTC EXTENDED WARNING: Geomagnetic K-Index of 6 expected Extension to Serial Number: 475 Valid From: 2023 Mar 23 1420 UTC Now Valid Until: 2023 Mar 24 0300 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 55 degrees Geomagnetic Latitude. Induced Currents –