Solar Storm Watch Issued as Powerful CME Set to Strike Earth

August 31, 2025 - Today, space weather forecasters warned of an incoming solar storm that may spark spectacular auroral displays and modest technology disruptions over the Labor Day weekend.

According to NOAA’s Space Weather Prediction Center (SWPC), a coronal mass ejection (CME) launched by an M2.7-class solar flare from sunspot AR 4199 on August 30 is expected to impact Earth late on September 1 and into September 2 (UTC), initiating a G2 (moderate) geomagnetic storm and possibly intensifying to G3 (strong) levels as the main storm arrives.

Dr. Tamitha Skov, a space weather physicist, highlighted on X (formerly Twitter) that two sequential CMEs may merge en route to Earth, forming a so-called “cannibal CME” that could produce an initial disturbance followed by a stronger storm. “Impact is expected by late September 1. G2+ conditions possible,” she explained.

Under G3 storm conditions, NOAA modelling indicates the auroral oval could expand well beyond the Arctic Circle, offering skywatchers in the northern U.S., Canada, and parts of Europe a chance to see northern lights as far south as Illinois and Germany. The UK Met Office similarly predicts auroras might be visible under clear skies across East Anglia, the Midlands, and Wales.

While the storm poses minimal risk to everyday technology, high-latitude regions may experience intermittent HF radio blackouts, satellite navigation errors, and slight voltage fluctuations in power grids. Satellite operators are advised to monitor increased atmospheric drag and potential surface charging on spacecraft.

Skywatchers are encouraged to seek dark, unobstructed northern horizons after local midnight on the nights of September 1-2. The first quarter Moon will set around midnight, providing optimal darkness for aurora viewing.

NOAA’s Elsayed Talaat noted that although Solar Cycle 25 is at its maximum phase, pinpointing the exact solar peak will require months of data. “More surprises like this CME can occur at any time,” he cautioned, reminding observers and operators to remain vigilant as the cycle continues to ramp up.

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