X-FLARE! (UPDATED): Active sunspot AR3386 erupted again on Aug. 5th (2221 UT), producing a long-duration X1.6-class solar flare. NASA's Solar Dynamics Observatory recorded the extreme ultraviolet flash:

The flare ionized the top of Earth's atmosphere. This, in turn, caused a shortwave radio blackout over the Pacific Ocean: map. Mariners and ham radio operators may have noticed loss of signal and other propagation effects at frequencies below 30 MHz. 

A CME is emerging from the blast site. It is not heading directly for Earth, but its flank might deliver a glancing blow on Aug. 8th or 9th, adding its energy to that of another CME already en route. Stay tuned for an updated forecast after we receive more data from SOHO coronagraphs. Solar flare alerts: SMS Text

SpaceWeather.com