This aurora came about from a "coronal hole", where the solar wind can blow directly from the Sun. The hole was nearly dead center and very large, and hit the Earth strong enough to become visible at middle latitudes. The Kp index averaged 6, which is very often at the low limit of igniting a noticeable glow on the northern horizon, and initially that is how it started, but given time it erupted with a few moderately weak spires, and even a northwesterly red coloration. Indeed it was a bit of a surprise that the event was decent, and also the best observed aurora here in 7 years, but was still falls far short of the best events I have seen from here over the decades.