A G2 – Moderate geomagnetic storm watch has been issued by the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center (SWPC) for August 8, 2025. The watch is followed by a G1 – Minor storm watch on August 9.
The alert is based on forecasts predicting the arrival of a coronal mass ejection (CME) associated with an M4.4 solar flare that erupted at 15:53 UTC on August 5.
The CME is expected to arrive during the first half of August 8, accompanied by a co-rotating interaction region (CIR) originating from a large southern hemisphere coronal hole. This combined solar wind structure is forecast to enhance interplanetary magnetic field strength, density, and speed, triggering geomagnetic storm conditions.
The area of expected impact is primarily poleward of 55° geomagnetic latitude. Anticipated effects include possible power grid fluctuations, particularly in high-latitude power systems where voltage alarms may be triggered. Satellite operations may be affected by orientation irregularities and increased drag on low Earth orbit satellites.
High frequency (HF) radio propagation may experience degradation at higher latitudes. Auroral activity could extend farther south than usual, potentially becoming visible as far south as New York, Wisconsin, and Washington state in the United States.
Solar activity is expected to continue at moderate levels with a high chance for M-class flares (55%), and a slight chance for X-class (10%) through August 9. Higher probabilities are being driven by the complexity and current activity of Region 4168.