G1 – Minor Geomagnetic Storm Alert issued on October 12

A G1 – Minor Geomagnetic Storm Alert was issued on October 12, 2025. The Alert, released at 18:49 UTC, indicates the K-index reached a value of 5 at 18:42 UTC. The valid period for this alert extends from 18:00 UTC to 21:00 UTC. The NOAA Space Weather Prediction Center (SWPC) currently lists the alert as active.

According to official guidance, G1 – Minor Geomagnetic Storms primarily impact regions poleward of 60 degrees geomagnetic latitude. Potential effects include weak power grid fluctuations, minor impacts on satellite operations, and the possible visibility of auroras at high latitudes, such as the northern tier of the United States—including northern Michigan and Maine.

This geomagnetic activity is being driven by persistent enhanced solar wind conditions associated with a negative polarity coronal hole high speed stream (CH HSS) located at the northwest quadrant of the solar disk. Solar wind speeds have been recorded between 400 km/s and 750 km/s. SWPC forecasts indicate that active to G1 – Minor storm levels are expected to persist over October 12 and 13 due to continued influence from the coronal hole high speed stream.