A significant geomagnetic storm, classified as G3 (strong), is anticipated to impact Earth between September 1st and 2nd, 2025. This event is a consequence of a powerful coronal mass ejection (CME) originating from the Sun.
NOAA's Space Weather Prediction Center has issued an alert, indicating that a stream of solar wind, propelled by an M2.7 class solar flare from active region AR 4199 on August 30th, 2025, is en route to our planet. The solar wind stream's trailing edge is expected to escalate the phenomenon to a G3 level, potentially causing auroral displays visible at lower latitudes than usual. Some forecasts suggest the possibility of G4 (severe) conditions if successive solar flows merge, amplifying their impact.
This influx of charged particles carries the potential to disrupt technological systems. Impacts could include interference with radio communications, malfunctions in satellites, and instability in power grids. While concerning, the predicted intensity does not represent an extreme G5 event. Under G3 conditions, power systems may experience voltage irregularities, and spacecraft could face increased drag or charging issues. Satellite navigation systems like GPS might also suffer intermittent disruptions.
The CME responsible for this alert was generated following an M2.7 class solar flare associated with active region AR 4199. The phenomenon of a "cannibal CME," where a faster solar ejection overtakes a slower one, may contribute to the storm's intensity. Auroras, typically seen at high latitudes, may be visible in mid-latitude regions. Forecasters suggest that under G3 conditions, auroral glows could extend as far south as states like Oregon, Illinois, and New York in the U.S., and similarly in Europe. The best viewing times are anticipated to be during the night of September 1st into the early morning of September 2nd, provided skies are clear and light pollution is minimal. The proximity to the equinox is also noted as a factor that can contribute to the strengthening of auroras.
Scientists emphasize that the Sun is currently near the peak of its 11-year cycle, leading to heightened solar activity. This means that further geomagnetic events are possible in the coming months. The NOAA Space Weather Prediction Center continuously monitors solar activity and issues watches, warnings, and alerts to inform critical infrastructure operators and the public about potential space weather impacts.