Space Weather Message Code: WARK04 Serial Number: 3222 Issue Time: 2017 May 23 0545 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2017 May 23 0544 UTC Valid To: 2017 May 23 1200 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: WARK04 Serial Number: 3221 Issue Time: 2017 May 21 1755 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 3220 Valid From: 2017 May 19 1614 UTC Now Valid Until: 2017 May 22 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 65 degrees Geomagnetic Latitude. Induced Currents –

Space Weather Message Code: WARK05 Serial Number: 1353 Issue Time: 2017 May 20 1450 UTC EXTENDED WARNING: Geomagnetic K-index of 5 expected Extension to Serial Number: 1352 Valid From: 2017 May 20 0729 UTC Now Valid Until: 2017 May 20 2100 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: WARK05 Serial Number: 1352 Issue Time: 2017 May 20 0730 UTC WARNING: Geomagnetic K-index of 5 expected Valid From: 2017 May 20 0729 UTC Valid To: 2017 May 20 1500 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: 3220 Issue Time: 2017 May 20 0241 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 3219 Valid From: 2017 May 19 1614 UTC Now Valid Until: 2017 May 21 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: ALTK04 Serial Number: 1978 Issue Time: 2017 May 20 0240 UTC ALERT: Geomagnetic K-index of 4 Threshold Reached: 2017 May 20 0235 UTC Synoptic Period: 0000-0300 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: 3219 Issue Time: 2017 May 19 1614 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2017 May 19 1614 UTC Valid To: 2017 May 20 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: ALTK04 Serial Number: 1977 Issue Time: 2017 May 18 0139 UTC ALERT: Geomagnetic K-index of 4 Threshold Reached: 2017 May 18 0139 UTC Synoptic Period: 0000-0300 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: 3218 Issue Time: 2017 May 18 0119 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2017 May 18 0115 UTC Valid To: 2017 May 18 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: WATA30 Serial Number: 160 Issue Time: 2017 May 17 1752 UTC WATCH: Geomagnetic Storm Category G2 Predicted Highest Storm Level Predicted by Day: May 18: G1 (Minor) May 19: G2 (Moderate) May 20: 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