My meters, graphs and gauges indicate a chance for northern lights overnight for the northern U.S. and southern Canada. Although the official forecast doesn’t sound promising, the Kp index, an indicator of magnetic activity overhead, is in the yellow zone (Kp=4) and satellite plots of the auroral oval show it spreading across Canada and pushing southward toward the U.S. border. This as of 10:30 p.m. CDT.
Either a coronal mass ejection – an outburst of high speed subatomic particles from the sun – or a stronger than usual gust of solar wind from a coronal hole is behind the enhanced activity. Coronal holes are open regions in the sun’s atmosphere not buckled down by solar magnetism. Strong winds of electrons and protons can flow from the holes and spark auroras on Earth.
Unfortunately I can’t do a sky check here in Duluth because the only thing pouring from my sky tonight is rain. Chances for more auroras continue through tomorrow evening Oct. 15-16. As always, keep an eye.