Geomagnetic Storm Continues; Auroras Down to Illinois Possible Tonight

The Planetary K index remains at unusually high levels between 5 and 6, indicative of a G2 geomagnetic storm ongoing across Earth. Effects of a G2 storm include:


-High latitude power issues
-Transformer damage from prolonged storms
-Spacecraft orbit issues
-Auroras seen as far south as New York and Idaho

This geomagnetic storm is expected to continue for a little while longer.

The K index does something more than tell the strength of a geomagnetic storm. It can also tell how far south the Aurora Borealis, or Northern Lights, may extend. Let's take a look.

When the K index is at 5, like it has been recently, the aurora borealis can be seen as far south as northern Michigan into Maine. When at 7, the aurora can be spotted through the Northeast and Lower Great Lakes into the Northern Plains.

Using the observed K index, as well as observed data from the ACE spacecraft roughly 1 million miles from Earth, I would expect the aurora borealis to extend to the 5 line shown above, with the potential of sightings of the Northern Lights in areas just to the south of that 5 line. I would not count aurora sightings in extreme southern Wisconsin/northern Illinois out this evening, although the potential is not too great.

Andrew