SOLAR FLARE UPDATE: NOAA forecasters say that a CME hurled into space by today's M6.7-flare might deliver a glancing blow to Earth's magnetic field on April 20th. High-latitude sky watchers should be alert for auroras during a possible G1-class geomagnetic storm.
BIG SUNSPOT ERUPTS: Surprise! Quiet sunspot AR2529 isn't so quiet, after all. The heart-shaped active region erupted on April 18th (00:39 UT), producing a strong M6.7-class solar flare and shortwave radio blackouts around the Pacific. Visit http://spaceweather.com for more information.
A pulse of UV radiation from the flare ionized the top of Earth's atmosphere. This, in turn, disrupted shortwave radio communications over the daylit side of our planet. Mariners, aviators, and ham radio operators around the Pacific Ocean may have noticed fading signals at frequencies below ~15 MHz. A NOAA blackout map shows the frequencies and territories affected.
More M-class flares are possible in the days ahead. AR2529 has developed a 'beta-gamma' magnetic field that harbors plenty of energy for this kind of explosion. Although the sunspot is no longer directly facing Earth, it can still affect our planet by causing radio blackouts and glancing-blow CMEs. Stay tuned.