G1 – Minor Geomagnetic Storm Alert issued on June 30

A G1 – Minor Geomagnetic Storm Alert was issued on June 30, 2026 by the NOAA Space Weather Prediction Center. The Alert was triggered when the geomagnetic K-index reached 5 at 20:27 UTC. The Alert is active for the synoptic period from 18:00 to 21:00 UTC on June 30.

According to NOAA, the area of impact is primarily poleward of 60 degrees geomagnetic latitude. Possible impacts include weak power grid fluctuations and minor effects on satellite operations. Aurora may be visible at high latitudes, such as the northern tier of the United States, including northern Michigan and Maine.

The triggering event for this alert is associated with enhanced geomagnetic activity following the likely arrival of a coronal mass ejection (CME) that left the Sun on June 26–27, 2026. Solar wind parameters showed a weak enhancement, with an increase in the total field and a southern deflection of the Bz component, coinciding with the onset of storm activity. Earlier in the period, moderate solar flare activity was observed, including M1.3 and M1.4 flares from active regions 4475 and 4479. Geomagnetic conditions are expected to return to mostly quiet levels after July 2.