G1 – Minor Geomagnetic Storm Alert issued on May 4, 2026

A G1 – Minor Geomagnetic Storm Alert was issued on May 4, 2026. The alert confirms that the geomagnetic K-index reached 5 at 23:55 UTC. The alert is valid for the synoptic period from 21:00 to 24:00 UTC on May 4, 2026.

Potential impacts from this geomagnetic storm are primarily expected poleward of 60 degrees geomagnetic latitude. Weak power grid fluctuations may occur in these areas, and minor impacts on satellite operations are possible. Aurora may be visible at high latitudes, potentially observable in the northern tier of the U.S., including areas such as northern Michigan and Maine.

According to the latest SWPC forecast discussion, solar wind parameters reflected weak influences from a negative polarity coronal hole high speed stream (CH HSS), with total interplanetary magnetic field mostly below 5 nT and no significant deflections. No Earth-directed coronal mass ejections (CMEs) were observed. The geomagnetic field is expected to remain at quiet to unsettled levels as these influences wane.