A beautiful aurora lit up the sky last night above the high latitudes. Some people as far south as Albert were able to see the lights, thanks to a G3-strong geomagnetic storm that emanated from a coronal hole on the surface of the sun.
The same region caused a G2-moderate storm last month, and lit up a brilliant aurora in the process. Yesterday’s storm was stronger, but we didn’t see the aurora south of Canada. But this region could also generate a storm next month around Nov. 21.
We watch the planetary K-index to determine how far south the aurora will reach. If it’s at 7 and the sky is dark, areas in the Midwest could see the northern lights, especially with a long-exposure photo. If it spikes higher than 7, it’s possible that areas in the Midwest could see it with the naked eye, and people in the D.C. region could catch it in a photo.
Yesterday the K-index peaked at 7 late in the afternoon and then faded to 5 and 6 after dark in North America. That means the Lower 48 was out of luck, but Canada and other higher latitudes got some beautiful photos of the light show.