Geomagnetic Storm underway – May 12, 1250UTC – 1800UTC

WARNING: Geomagnetic K-index of 7 or greater expected

Valid From: 2021 May 12 1250 UTC

Valid To: 2021 May 12 1800 UTC

Warning Condition: Onset

NOAA Scale: G3 or greater – Strong to Extreme

NOAA Space Weather Scale descriptions can be found at

Potential 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.