Overview

• A Coronal Mass Ejection from a May 31 M8.1 solar flare arrived on June 1 at speeds exceeding 1,000 km/s.
• Space Weather Prediction Center forecasters confirmed G4 (Severe) storm conditions after solar wind observatories recorded a strong southward magnetic field.
• Auroras have been reported from Washington and Michigan to Alabama and Northern California, with the best viewing between 10 p.m. and 2 a.m. local time.
• High-voltage grid operators and satellite controllers have been alerted to implement protective measures against geomagnetically induced currents.
• The storm coincides with the rising phase of Solar Cycle 25’s maximum, with elevated solar activity expected to continue into 2026.