Space Weather Message Code: WARK05 Serial Number: 1349 Issue Time: 2017 Apr 23 1821 UTC EXTENDED WARNING: Geomagnetic K-index of 5 expected Extension to Serial Number: 1348 Valid From: 2017 Apr 21 1920 UTC Now Valid Until: 2017 Apr 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 60 degrees Geomagnetic Latitude. Induced Currents –

Space Weather Message Code: ALTK05 Serial Number: 1110 Issue Time: 2017 Apr 23 1802 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2017 Apr 23 1759 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: ALTK05 Serial Number: 1109 Issue Time: 2017 Apr 23 1444 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2017 Apr 23 1442 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: ALTK05 Serial Number: 1108 Issue Time: 2017 Apr 23 1034 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2017 Apr 23 1034 UTC Synoptic Period: 0900-1200 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: 385 Issue Time: 2017 Apr 23 0852 UTC EXTENDED WARNING: Geomagnetic K-Index of 6 expected Extension to Serial Number: 384 Valid From: 2017 Apr 22 2255 UTC Now Valid Until: 2017 Apr 23 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 55 degrees Geomagnetic Latitude. Induced Currents –

Space Weather Message Code: ALTK05 Serial Number: 1107 Issue Time: 2017 Apr 23 0754 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2017 Apr 23 0754 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: ALTK06 Serial Number: 430 Issue Time: 2017 Apr 23 0001 UTC ALERT: Geomagnetic K-index of 6 Threshold Reached: 2017 Apr 22 2359 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: WARK06 Serial Number: 384 Issue Time: 2017 Apr 22 2255 UTC WARNING: Geomagnetic K-Index of 6 expected Valid From: 2017 Apr 22 2255 UTC Valid To: 2017 Apr 23 0900 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: 1106 Issue Time: 2017 Apr 22 2240 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2017 Apr 22 2240 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: WATA30 Serial Number: 155 Issue Time: 2017 Apr 22 2046 UTC WATCH: Geomagnetic Storm Category G2 Predicted Highest Storm Level Predicted by Day: Apr 23: G2 (Moderate) Apr 24: G1 (Minor) Apr 25: 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 55 degrees Geomagnetic Latitude. Induced Currents