"Later, however, Young sent Sky & Telescope an update: the CME's initial velocity was less than initially thought, about 875 miles (1,400 km) per second. Therefore, the shock front now crossing interplanetary space should reach Earth on Friday at about 12h Universal Time (5 a.m. Pacific Daylight Time). The SWPC's predicted geomagnetic disturbance is G3, a medium-intensity level that could trigger auroras over locations roughly northward of latitude 45° north (Oregon, Illinois, New England, and northern Europe). - See more at: http://www.skyandtelescope.com/astronomy-news/observing-news/powerful-solar-flare-091020143/#sthash.uOfeivu8.dpuf"
http://www.skyandtelescope.com/astronomy-news/observing-news/powerful-solar-flare-091020143/