156
WOXX20 KWNP 181841
WATA20

Space Weather Message Code: WATA20
Serial Number: 1056
Issue Time: 2025 Aug 18 1839 UTC

WATCH: Geomagnetic Storm Category G1 Predicted
Highest Storm Level Predicted by Day:
Aug 19:  G1 (Minor)   Aug 20:  G1 (Minor)   Aug 21:  None (Below G1)
THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

Comment: Isolated periods of G1 (Minor) geomagnetic storming are likely 19 August due to recurrent, negative polarity CH HSS effects. Isolated periods of G1 (Minor) geomagnetic storming are likely again on 20 August with continued CH HSS effects coupled with the possibility of glancing influences from a CME that left the Sun on 17 August.
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.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

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