Mere hours after emerging over the sun's eastern limb on Dec. 31st, big sunspot AR3536 erupted, producing a major X5-class solar flare. NASA's Solar Dynamics Observatory (SDO) recorded the extreme ultraviolet flash:
This is the strongest flare of Solar Cycle 25 (so far) and the most powerful eruption the sun has produced since the great storms of Sept. 2017.
Radiation from the flare has caused a deep shortwave radio blackout over the Pacific Ocean: blackout map. Mariners and ham radio operators may have noticed loss of signal at all frequencies below 30 MHz for more than 60 minutes after the flare's peak (2155 UT).
The explosion also caused a solar tsunami. The blast wave can be seen in this animation from SDO:
Solar tsunamis are closely linked to CMEs. Indeed, coronagraph images from the Solar and Heliospheric Observatory (SOHO) show a CME emerging from the blast site.
Normally we would expect a CME leaving the sun's extreme-eastern limb to have no Earth-directed component. This case appears to be different. According to a NASA model, the CME will graze our planet Jan. 2nd. G2-class geomagnetic storms are possible when the CME arrives.
SOURCE: https://www.spaceweather.com/