Space Weather Message Code: ALTK06 Serial Number: 441 Issue Time: 2017 Sep 08 0028 UTC ALERT: Geomagnetic K-index of 6 Threshold Reached: 2017 Sep 08 0027 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: 1148 Issue Time: 2017 Sep 08 0022 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2017 Sep 08 0022 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: ALTK08 Serial Number: 23 Issue Time: 2017 Sep 07 2350 UTC ALERT: Geomagnetic K-index of 8 Threshold Reached: 2017 Sep 07 2350 UTC Synoptic Period: 2100-2400 UTC Active Warning: Yes NOAA Scale: G4 – Severe NOAA Space Weather Scale descriptions can be found at www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 45 degrees Geomagnetic Latitude. Induced Currents – Possible widespread voltage control problems and

Space Weather Message Code: ALTK07 Serial Number: 106 Issue Time: 2017 Sep 07 2325 UTC ALERT: Geomagnetic K-index of 7 Threshold Reached: 2017 Sep 07 2325 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: ALTK06 Serial Number: 440 Issue Time: 2017 Sep 07 2306 UTC ALERT: Geomagnetic K-index of 6 Threshold Reached: 2017 Sep 07 2302 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: 1147 Issue Time: 2017 Sep 07 2257 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2017 Sep 07 2256 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: WARK06 Serial Number: 395 Issue Time: 2017 Sep 07 2244 UTC WARNING: Geomagnetic K-Index of 6 expected Valid From: 2017 Sep 07 2255 UTC Valid To: 2017 Sep 08 0600 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: WARK04 Serial Number: 3309 Issue Time: 2017 Sep 07 1426 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 3308 Valid From: 2017 Sep 06 2330 UTC Now Valid Until: 2017 Sep 08 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: 3308 Issue Time: 2017 Sep 07 0902 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 3307 Valid From: 2017 Sep 06 2330 UTC Now Valid Until: 2017 Sep 07 1800 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: 1393 Issue Time: 2017 Sep 07 0857 UTC EXTENDED WARNING: Geomagnetic K-index of 5 expected Extension to Serial Number: 1392 Valid From: 2017 Sep 07 0003 UTC Now Valid Until: 2017 Sep 07 1500 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 60 degrees Geomagnetic Latitude. Induced Currents –