A large, previously active sunspot has rotated toward Earth over the past week, elevating our solar flare and geomagnetic storm chances in an otherwise quiet period of space weather. Sunspot AR2339 is the largest sunspot on the Earth-visible side, and has been been grumbling out some low-level, C-class flare activity with minor radio impacts over the past couple of days. It hasn’t produced any large flares since one week ago when it whipped out an X-class flare just after coming into view on the Sun’s horizon. The X2 flare did have an associated coronal mass ejection, but since it was pointed out into space, Earth did not get a geomagnetic storm (or aurora) from the event.

Given AR2339’s size — much larger than the planet Earth itself — and its recently active history, the Space Weather Prediction Center is forecasting a 30 percent chance of at least an M-class solar flare over the next two days, and a five percent chance of an X-class flare.High-latitude skywatchers will likely continue to see some active aurora nights over the next couple of days. “An interplanetary shock wave hit Earth’s magnetic field during the early hours of May 12th,” says spaceweather.com, “setting the stage for auroras. NOAA forecasters estimate a 60% chance of geomagnetic storms.” FULL REPORT