After the X-class flare on 1 December, the Sun was relatively quiet despite the large and complex sunspot groups present. Then, late on 6 December, NOAA 4299 produced another strong flare. Based on the SIDC's forecaster PRESTO:
- A halo coronal mass ejection (SIDC CME 605) was first detected in the LASCO/C2 coronagraphic imagery starting at 19:24 UTC on 6 December ... . The CME is associated with the M8.1 flare from SIDC Sunspot Group 687 (NOAA Active Region 4299) that peaked on 20:39 UTC. Related Type II radio emissions were registered between 20:40 UTC and 20:56 UTC on 6 December (NOAA/USAF), and a large coronal dimming with post-eruptive arcade was detected as well (see the SDO/AIA imagery underneath). The CME has an estimated velocity of 850 km/s and is directed predominantly to the north-east.
- Preliminary analysis suggests a possible arrival at Earth late on 8 to early 9 December, which may result in a strong geomagnetic storm (Kp = 7).
- Small enhancements in the proton flux were registered as a result from this M-class flare, but no proton events were observed and the greater than 10 MeV GOES proton flux has remained below 10 pfu. Further enhancements of the proton flux are possible in case of new strong flaring activity and there are chances for mild particle acceleration from the observed halo CME."
Solar activity then shifted into a higher gear on 8 December with 3 M-class flares and an X1.1 flare in less than 7 hours. An M2.4 in NOAA 4299 (same source location as the M8 flare) peaked at 00:12 UTC. M-class flares were also observed at 00:36 (M2.0) from the large sunspot group NOAA 4294, and an M1.8 at 06:54 UTC from a filament eruption in a small active region just east of NOAA 4299. In between, a short-lived X1.1 flare erupted from NOAA 4298, a relatively simple sunspot group to the west of NOAA 4294. Imagery in H-alpha (a line in the red portion of the solar spectrum ; see GONG imagery underneath and this compilation) and extreme ultraviolet seem to indicate material was ejected from the Sun, but it remains to be seen if any associated CME has an earth-directed component. Standing-by additional coronagraphic imagery and the analysis of the SIDC space weather forecaster.
