A federal weather-monitoring agency says the northern lights may be visible from northern U.S. and Canada through Friday, predicting powerful geomagnetic storms.
The National Oceanic and Atmospheric Administration issued a G3 (strong) geomagnetic storm watch, with isolated periods potentially reaching G4 (severe) levels, making the aurora visible across 23 states in the Northeast, the Midwest and the West.
Geomagnetic storms are disturbances in Earth’s magnetic field caused by solar activity. They produce the colorful ribbons of green, red and purple light known as the northern lights, or aurora borealis, in the Northern Hemisphere.
Stronger instances can disrupt radio communications, GPS systems and satellite operations. NOAA rates geomagnetic storms on a scale of G1 (minor) to G5 (extreme).
The event is driven by a combination of solar disturbances, including multiple coronal mass ejections — massive bursts of plasma and magnetic energy released from the sun’s surface — combined with a high-speed solar wind stream.
A G1 geomagnetic storm is expected Thursday because three separate solar wind disturbances may arrive at Earth simultaneously, increasing the chances of aurora activity. A G3 or G4 storm is possible Friday.
A bright waning gibbous moon rising after midnight could interfere with fainter aurora displays. Note that space-weather forecasts are subject to rapid change.
