Space Weather Message Code: ALTK08

Serial Number: 23

Issue Time: 2017 Sep 07 2350 UTC

ALERT: Geomagnetic K-index of 8

Threshold Reached: 2017 Sep 07 2350 UTC

Synoptic Period: 2100-2400 UTC

Active Warning: Yes

NOAA Scale: G4 - Severe

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-explanation

Potential Impacts: Area of impact primarily poleward of 45 degrees Geomagnetic Latitude.

Induced Currents - Possible widespread voltage control problems and some protective systems may mistakenly trip out key assets from the power grid. Induced pipeline currents intensify.

Spacecraft - Systems may experience surface charging; increased drag on low earth orbit satellites, and tracking and orientation problems may occur.

Navigation - Satellite navigation (GPS) degraded or inoperable for hours.

Radio - HF (high frequency) radio propagation sporadic or blacked out.

Aurora - Aurora may be seen as low as Alabama and Northern California