Positive polarity CH HSS sparks G3 – Strong geomagnetic storm
A G3 (Strong) geomagnetic storm is in progress on October 2, 2025, driven by a positive-polarity coronal hole high-speed stream (CH HSS). The U.S. Space Weather Prediction Center (SWPC) issued an active warning valid until 12:00 UTC, with aurora sightings possible as far south as Pennsylvania, Iowa, and Oregon.

