ALERT: Geomagnetic K-index of 4 Alert issued on June 24

An ALERT: Geomagnetic K-index of 4 was issued by NOAA SWPC on June 24, 2026, after the K-index threshold was reached at 17:46 UTC. The alert is valid for the synoptic period between 15:00 and 18:00 UTC, with an active warning currently in effect.

Potential impacts from this event are expected to occur primarily poleward of 65 degrees geomagnetic latitude. These impacts include the possibility of weak power grid fluctuations due to induced currents. In addition, aurora may be visible at high latitudes such as Canada and Alaska. These impacts remain consistent with the thresholds and expectations for a K-index of 4 event on the NOAA Space Weather Scales.

According to the latest Forecast Discussion issued by NOAA’s Space Weather Prediction Center, the geomagnetic activity is associated with enhanced solar wind conditions. These are expected to continue through June 26 due to the anticipated onset of negative polarity coronal hole high-speed stream (CH HSS) influences, as well as a potential minor glancing blow from a CME that left the Sun on June 20. The geomagnetic field has been at quiet to unsettled levels, but periods of active conditions are likely to persist over the coming days.