This is the fourth X-class solar flare since November 9, and the sixth since November 4. If we look just at Region 4274, this is its fifth X-class since X1.8 at 17:34 UTC on November 4, X1.7 at 07:35 UTC on November 9, X1.2 at 09:19 UTC on November 10, and X5.1 at 10:04 UTC on November 11.
A Type II Radio Emission, with an estimated velocity of 1 525 km/s, was associated with today’s X4.0 event, suggesting a coronal mass ejection (CME) was produced.
Source Region 4274 is positioned near the west limb of the Sun, a location that generally reduces the likelihood of producing Earth-directed CMEs. However, if the eruption generates a halo CME, it would still be expected to contain an Earth-directed component despite the unfavorable geometry.
Radio frequencies were forecast to be most degraded over SE Africa and the Indian Ocean at the time of the flare.
Additionally, the position of Region 4274 is highly favorable for proton storms, as regions near the west limb have optimal magnetic connectivity to Earth along the Parker spiral. Eruptions from this sector can inject energetic particles directly onto magnetic field lines that connect to Earth’s magnetosphere, increasing the likelihood of a rapid rise in proton flux and the onset of a radiation storm.
This is exactly what we see now on the GOES Proton Flux plot — a sharp rise in proton flux counts. It is likely we are about to see another episode of at least S1 – Minor solar radiation storm.
At 09:17 UTC, SWPC has issued an S1 storm warning, valid to 23:59 UTC today. S1 storms can cause minor impacts on polar HF (high frequency) radio propagation, resulting in fades at lower frequencies. About 50 such storms occur per 11-year solar cycle.
S1 – Minor Solar Radiation Storm threshold was reached at 09:20 UTC, about 50 minutes after the flare peaked.
This latest bout of increased solar activity over the past 7 days has brought us G4 – Severe geomagnetic storming, spectacular auroras all the way south to Mexico, and 3 days of solar radiation storming, peaking at S3 – Moderate levels on November 12.
Solar activity is expected to be low with moderate levels likely and a chance for X-class activity through November 16, mostly due to the flare potential of Region 4274.
