ALERT: Geomagnetic K-index of 4 Alert issued on July 8

A Geomagnetic K-index of 4 Alert was issued on July 8, 2025, by the NOAA Space Weather Prediction Center. The alert was triggered when the K-index reached 4 at 05:59 UTC during the synoptic period between 03:00 and 06:00 UTC. This alert remains active as of the latest update.

The area of impact is primarily poleward of 65 degrees geomagnetic latitude. According to the alert, induced currents may result in weak power grid fluctuations, and aurora may be visible at high latitudes such as Canada and Alaska. These impacts are generally limited to high-latitude regions and do not typically affect lower latitudes.

According to the latest forecast discussion from NOAA SWPC, geomagnetic activity has been influenced by a negative polarity coronal hole high-speed stream (CH HSS). The geomagnetic field reached G1 – Minor storm levels during the 00:00–03:00 UTC period as a result of this influence. The field has been active to unsettled otherwise, and solar wind parameters are expected to remain mildly elevated through July 8 as CH HSS effects diminish.