INCOMING CME? A coronal mass ejection (CME) that flew off the sun’s western limb on May 17th might hit Earth after all. NOAA forecasters say a shock wave from the blast could deliver a glancing blow to Earth’s magnetic field on May 18th or 19th. The CME, pictured below, was propelled by an M5-class solar flare from departing sunspot AR1476.

The speckles in the movie are caused by energetic protons hitting the observatory’s detector. Those protons may have been accelerated in part by the shock wave en route to Earth.

According to NOAA, there is a 40% chance of minor geomagnetic storms and a 15% chance of strong storms when the shock arrives. High-latitude sky watchers should be alert for auroras.

fr/spaceweather.com