ALERT: Geomagnetic K-index of 8 -- ALERT: Geomagnetic K-index of 8

Space Weather Message Code: ALTK08
Serial Number: 21
Issue Time: 2015 Jun 22 1858 UTC

ALERT: Geomagnetic K-index of 8
Threshold Reached: 2015 Jun 22 1852 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G4 - Severe

NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/NOAAscales

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.

SEVERE GEOMAGNETIC STORM IN PROGRESS: A severe G4-class geomagnetic
storm is in progress on June 22nd. This follows a series of
rapid-fire CME strikes to Earth's magnetic field during the past
24 hours. Magnetic fields in the wake of the latest CME are strongly
coupled to Earth's own magnetic field. This is a condition that could
sustain the geomagnetic storm for many hours to come. High- and
mid-latitude sky watchers should be alert for auroras tonight,
especially during the hours around local midnight.