EXTENDED WARNING: Geomagnetic K-index of 4 expected

A geomagnetic K-index of 4 is expected, prompting an extended warning from the NOAA Space Weather Prediction Center. This is exciting news for sky-watchers, as it indicates a higher likelihood of visible aurora at high latitudes. Sky-watchers in Canada and Alaska may be able to see aurora, and should look for weak power grid fluctuations as a sign of the geomagnetic activity.