Scandinavians were the lucky ones yesterday when auroras broke out during their nighttime. Here in the U.S. it was still afternoon. Auroras are mighty scarce in sunshine.
Tonight to my surprise, we had a brief display around 11 p.m. CDT. An arc rose above Boulder Lake north of Duluth, Minn., where a group of naturalists and I spent the night at the telescope under a starry sky. At the sight of a few needle-thin rays, one in our group jumped in a canoe and paddled out into the lake for a better view.
Not 15 minutes after it began, the arc and rays faded away, leaving only a faint, diffuse glow until fog settled in around midnight. The Kp index rose slightly during the evening, and the ACE satellite plot has shown a southward pointing Bz or solar magnetic field in Earth’s vicinity for many hours. This is often a good indicator of auroral activity on the way.
The show was subtle but no one was disappointed. Auroras are always welcome around here.