NOAA forecasters say there is a 55% to 60% chance of geomagnetic storms on May 15th and 16th when a series of coronal mass ejections (CMEs) could hit Earth’s magnetic field. Storm levels are expected to range between category G1 and G2. This means auroras could be sighted in northern-tier US states such as Montana, Minnesota, and upstate New York.
Three and possibly four CMEs are en route to Earth following a series of explosions near sunspot AR2741. The most potent so far occurred on May 12th when a filament of magnetism surrounding the sunspot became unstable and erupted. The blast zone was more than 200,000 km in diameter:
Full story at Spaceweather.com