For the 3rd day in a row, active sunspot AR3078 is producing strong M-class solar flares. The latest, an M2-category explosion on Aug. 17th (1345 UT), hurled a plume of cool dark plasma into space:
A CME will almost certainly emerge from the blast site (confirmation awaits fresh data from SOHO). But will it hit Earth? Like all the other CMEs AR3078 has produced this week, this one will skate the southern edge of the Earth strike zone. If it does hit us, the blow will be grazing, not full strength. However, even a grazing blow can cause a geomagnetic storm.