The northern lights could return to the sky over parts of Canada as a sunspot that contributed to a recent stunning aurora display rotates back Earth-side.

A sunspot that earlier this month unleashed a series of solar flares and the largest in nearly two decades has turned back toward Earth and let loose another powerful, but less intense, flare this week.

The U.S. National Oceanic and Atmospheric Administration, which rates geomagnetic storms on a five-point scale, is forecasting a moderate G2 storm peaking Friday, compared to the severe G4 storm in early May.