K-index of 4 – Geomagnetic Storm Alert issued on July 3

An ALERT: Geomagnetic K-index of 4 was issued on July 3, 2025, by NOAA’s Space Weather Prediction Center. The threshold was reached at 14:40 UTC, with the alert covering the synoptic period from 12:00 to 15:00 UTC. This alert indicates geomagnetic field activity approaching active storm conditions.

According to the alert, potential impacts are expected primarily poleward of 65 degrees geomagnetic latitude. Weak power grid fluctuations can occur due to induced currents. Additionally, aurora may be visible at high latitudes, such as across Canada and Alaska.

The latest forecast discussion notes that enhancements in the interplanetary magnetic field (IMF) on July 3 are likely due to the arrival of a coronal mass ejection (CME) that left the Sun on June 28, 2025. This event is contributing to the increased geomagnetic activity observed today.