Universe Today
The Solar Dynamics Observatory captured this view as the Sun let loose with its biggest solar flare of the year so far. It's not a real big one -- a mid-level flare classified as an M6.5 – but an associated coronal mass ejection is heading towards Earth and could spur some nice auroae by this weekend.
Spaceweather.com
predicts the expanding cloud (see animation below) will probably deliver a glancing blow to Earth's magnetic field late on April 12th or more likely April 13th. The
NOAA Space Prediction Center
forecasts this event to cause moderate (G2) Geomagnetic Storm activity, and predicts geomagnetic activity to start in the mid to latter part (UTC) of April 13. They add that the source region is still potent and well-positioned for more geoeffective activity in the next few days.
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The magnetic field of sunspot AR1719 erupted on April 11th at 0716 UT, producing an M6-class solar flare. Coronagraph images from the Solar and Heliospheric Observatory show a CME emerging from the blast site of the M6.5 solar flare. Credit: NASA[/caption]
See this NASA page
for info on solar flares, CMEs, and more.
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NASA's Solar Dynamics Observatory captured this image of an M6.5 class flare at 3:16 am EDT on April 11, 2013. This image shows a combination of light in wavelengths of 131 and 171 Angstroms. Credit: NASA/SDO.[/caption]