Space Weather Message Code: ALTK05 Serial Number: 1323 Issue Time: 2021 Apr 16 2027 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2021 Apr 16 2025 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: WARK05 Serial Number: 1593 Issue Time: 2021 Apr 16 1923 UTC WARNING: Geomagnetic K-index of 5 expected Valid From: 2021 Apr 16 1925 UTC Valid To: 2021 Apr 17 0600 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: ALTK04 Serial Number: 2211 Issue Time: 2021 Apr 16 1840 UTC ALERT: Geomagnetic K-index of 4 Threshold Reached: 2021 Apr 16 1838 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

Space Weather Message Code: WARK04 Serial Number: 3878 Issue Time: 2021 Apr 16 1334 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2021 Apr 16 1335 UTC Valid To: 2021 Apr 16 2100 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: 1322 Issue Time: 2021 Apr 15 0901 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2021 Apr 15 0859 UTC Synoptic Period: 0600-0900 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: 1591 Issue Time: 2021 Apr 15 0712 UTC WARNING: Geomagnetic K-index of 5 expected Valid From: 2021 Apr 15 0712 UTC Valid To: 2021 Apr 15 1200 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: 3877 Issue Time: 2021 Apr 15 0548 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 3876 Valid From: 2021 Apr 14 2342 UTC Now Valid Until: 2021 Apr 15 1200 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: 2210 Issue Time: 2021 Apr 14 2358 UTC ALERT: Geomagnetic K-index of 4 Threshold Reached: 2021 Apr 14 2358 UTC Synoptic Period: 2100-2400 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: 3876 Issue Time: 2021 Apr 14 2343 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2021 Apr 14 2342 UTC Valid To: 2021 Apr 15 0600 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: WATA20 Serial Number: 894 Issue Time: 2021 Apr 14 1940 UTC WATCH: Geomagnetic Storm Category G1 Predicted Highest Storm Level Predicted by Day: Apr 15: None (Below G1) Apr 16: None (Below G1) Apr 17: 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.