AIA / LMSAL / NASA

A color-coded image from the Atmospheric Imaging Assembly on NASA's Solar Dynamics Observatory highlights the solar flare thrown off from the sun's disk today in shades of gold and yellow.

For the second day in a row, the sun has sent a blast of electrically charged particles toward Earth — and according to SpaceWeather.com, that means we're in for a double shot of geomagnetic activity early Saturday. But not to worry: The most noticeable effect of the twin M-class blasts should be heightened auroral displays.

Both of the coronal mass eruptions, or CMEs, originated in a sunspot region known as AR1504, which is currently pointing in Earth's direction. AR1504 has been shooting off a series of flares in recent days, including an M1.2-class flare on Wednesday and an M1.5 today. None of the flares have approached the X-class level, which would have the potential for significant disruptions in power grids or satellite-based communication.

SpaceWeather.com projects that the CMEs thrown off by those two flares will merge into one wave of particles that's due to hit Earth's magnetic field around 6:16 a.m. ET Saturday. The National Oceanic and Atmospheric Administration's Space Weather Prediction Center, meanwhile, predicts that the CME will arrive "late on 16 June." The prediction center noted that today's flare sparked a minor radio blackout and "has the potential" to produce more such storms.

Bottom line? Polar regions will have a better chance of seeing auroral lights over the weekend, although the midnight sun will put a damper on viewing in the north. If you catch a great auroral view, please consider sharing it with us via our FirstPerson upload page. In the meantime, keep a watch on SpaceWeather.com and the prediction center's Facebook page for updates — and feast your eyes on the imagery below:

NASA

NASA's STEREO-Ahead spacecraft records the massive coronal mass ejection thrown off by today's solar eruption. The glare of the sun's disk is blocked at the center of the image.

More sun imagery:

• Your views and videos of the Venus transit
• Thrill to a sunspot's parting shot
• Graphic: Anatomy of a solar storm
• Cosmic Log archive on the sun

Alan Boyle is msnbc.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.