EXTENDED WARNING: Geomagnetic K-index of 7 or greater expected
Extension to Serial Number: 77
Valid From: 2021 May 12 1250 UTC
Now Valid Until: 2021 May 12 2359 UTC
Warning Condition: Persistence
NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanationPotential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic Latitude.
Induced Currents - Power system voltage irregularities possible, false alarms may be triggered on some protection devices.
Spacecraft - Systems may experience surface charging; increased drag on low Earth-orbit satellites and orientation problems may occur.
Navigation - Intermittent satellite navigation (GPS) problems, including loss-of-lock and increased range error may occur.
Radio - HF (high frequency) radio may be intermittent.
Aurora - Aurora may be seen as low as Pennsylvania to Iowa to Oregon.