A long-duration solar flare measuring M2.7 at its peak erupted at 20:02 UTC on August 30, 2025. The eruption produced an asymmetric full halo coronal mass ejection (CME), with impact expected late on September 1 into September 2. A G3 – Strong geomagnetic storm watch is in effect.
The event began at 19:11 UTC, peaked at 20:02 UTC, and ended at 20:41 UTC. The eruption originated from Active Region 4199 (Beta), located near the center of the solar disk.
An asymmetric full halo CME was first observed in LASCO C3 imagery at approximately 20:30 UTC on August 30. Impact analysis suggest Earth-arrival after 20:00 UTC on September 1.
As a result, NOAA Space Weather Prediction Center (SWPC) has issued a G2 – Moderate geomagnetic storm watch for September 1 and G3 – Strong for September 2.
The primary area of potential impact is poleward of 50° geomagnetic latitude.
Under G3 geomagnetic storm conditions, power systems may experience voltage irregularities, with possible false alarms on some protection devices. Spacecraft could be affected by surface charging, increased drag on low Earth-orbit satellites, and orientation difficulties.
Satellite navigation systems (GPS) may be intermittently disrupted, with potential loss of lock and increased range errors. High frequency (HF) radio communications may also be intermittent while auroras could be visible as far south as Pennsylvania, Iowa, and Oregon.
Solar activity is forecast to remain at moderate levels over the next three days, with a 65% chance of M-class and a 20% chance of X-class solar flares through September 2.