On Monday (Sept. 4), the sun blasted out a huge cloud of superheated plasma known as a coronal mass ejection (CME). This fast-moving CME is expected to slam into Earth overnight Wednesday, triggering strong geomagnetic storms.

Such storms often supercharge Earth’s auroras, the ghostly displays of dancing color also known as the northern and southern lights. And that could be the case Wednesday night through early Thursday morning (Sept. 7): Auroras are likely to extend southward into the continental United States, from Washington and Idaho in the West to Indiana and Ohio in the Midwest and New England in the Northeast, according to the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center (SWPC).

The moon also happens to be full Wednesday night, unfortunately, so its glare will dampen the light show to some degree.

You can track the northern lights and see if they’re likely to reach your location, using SWPC’s 30-minute aurora forecast tool here: http://www.swpc.noaa.gov/node/45

The northern and southern lights are generated by charged solar particles hitting molecules in Earth’s atmosphere. The sky show is usually restricted to high latitudes, because our planet’s magnetic field tends to funnel these particles toward the poles.

CMEs are generally associated with solar flares — powerful outbursts of high-energy radiation. Monday’s CME fit this description, erupting along with an M5 flare from a sunspot known as AR 2673. (Scientists classify flares into one of three categories, depending on their strength: C-class flares are the weakest, M flares are medium-strength and X are the most powerful.)

Source: Space.com