Space Weather Message Code: ALTK04 Serial Number: 2537 Issue Time: 2025 Mar 21 1731 UTC ALERT: Geomagnetic K-index of 4 Threshold Reached: 2025 Mar 21 1730 UTC Synoptic Period: 1500-1800 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

Space Weather Message Code: WARK04 Serial Number: 4881 Issue Time: 2025 Mar 21 1712 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2025 Mar 21 1715 UTC Valid To: 2025 Mar 22 0900 UTC Warning Condition: Onset 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

Space Weather Message Code: ALTK05 Serial Number: 1720 Issue Time: 2025 Mar 19 2103 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2025 Mar 19 2059 UTC Synoptic Period: 1800-2100 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: WARK04 Serial Number: 4880 Issue Time: 2025 Mar 19 2052 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 4879 Valid From: 2025 Mar 17 0345 UTC Now Valid Until: 2025 Mar 20 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: WARK05 Serial Number: 1995 Issue Time: 2025 Mar 19 2039 UTC WARNING: Geomagnetic K-index of 5 expected Valid From: 2025 Mar 19 2039 UTC Valid To: 2025 Mar 20 0300 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

Space Weather Message Code: WARK05 Serial Number: 1994 Issue Time: 2025 Mar 19 0750 UTC WARNING: Geomagnetic K-index of 5 expected Valid From: 2025 Mar 19 0749 UTC Valid To: 2025 Mar 19 1800 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

Space Weather Message Code: WARK04 Serial Number: 4879 Issue Time: 2025 Mar 19 0515 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 4878 Valid From: 2025 Mar 17 0345 UTC Now Valid Until: 2025 Mar 19 2359 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: 4878 Issue Time: 2025 Mar 18 2352 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 4877 Valid From: 2025 Mar 17 0345 UTC Now Valid Until: 2025 Mar 19 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: WARK04 Serial Number: 4877 Issue Time: 2025 Mar 18 0556 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 4876 Valid From: 2025 Mar 17 0345 UTC Now Valid Until: 2025 Mar 18 2359 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: ALTK04 Serial Number: 2536 Issue Time: 2025 Mar 17 2102 UTC ALERT: Geomagnetic K-index of 4 Threshold Reached: 2025 Mar 17 2059 UTC Synoptic Period: 1800-2100 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