Space Weather Message Code: ALTK05 Serial Number: 1770 Issue Time: 2025 May 17 0053 UTC ALERT: Geomagnetic K-index of 5 Threshold Reached: 2025 May 17 0052 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: WARK05 Serial Number: 2043 Issue Time: 2025 May 17 0051 UTC WARNING: Geomagnetic K-index of 5 expected Valid From: 2025 May 17 0050 UTC Valid To: 2025 May 17 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: ALTK04 Serial Number: 2560 Issue Time: 2025 May 16 2336 UTC ALERT: Geomagnetic K-index of 4 Threshold Reached: 2025 May 16 2331 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: 4967 Issue Time: 2025 May 16 2256 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2025 May 16 2255 UTC Valid To: 2025 May 17 2359 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: 1041 Issue Time: 2025 May 16 1900 UTC WATCH: Geomagnetic Storm Category G1 Predicted Highest Storm Level Predicted by Day: May 17: None (Below G1) May 18: G1 (Minor) May 19: G1 (Minor) THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT Comment: Coronal Hole High Speed Stream influences will likely lead to G1 storm potential 18-19 May. NOAA Space Weather Scale descriptions can be

Space Weather Message Code: WARK04 Serial Number: 4966 Issue Time: 2025 May 16 0742 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2025 May 16 0742 UTC Valid To: 2025 May 16 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: WATA20 Serial Number: 1040 Issue Time: 2025 May 15 2252 UTC WATCH: Geomagnetic Storm Category G1 Predicted Highest Storm Level Predicted by Day: May 16: None (Below G1) May 17: None (Below G1) May 18: 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.

Space Weather Message Code: WARK05 Serial Number: 2042 Issue Time: 2025 May 15 0509 UTC WARNING: Geomagnetic K-index of 5 expected Valid From: 2025 May 15 0508 UTC Valid To: 2025 May 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: ALTK04 Serial Number: 2559 Issue Time: 2025 May 15 0349 UTC ALERT: Geomagnetic K-index of 4 Threshold Reached: 2025 May 15 0345 UTC Synoptic Period: 0300-0600 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: 4964 Issue Time: 2025 May 15 0333 UTC WARNING: Geomagnetic K-index of 4 expected Valid From: 2025 May 15 0332 UTC Valid To: 2025 May 15 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