New Delhi: A cluster of sunspots designated as Sunspot Group 687 by the Solar Influences Data Analysis Centre (SIDC) operated by the Royal Observatory of Belgium and Active Region 4274 by the US National and Oceanic Administration (NOAA) has fired off the fifth X-class solar flare. The X4.0 solar flare lasted for nearly an hour, peaking at 08:30 UTC on 14 November. After rotating into view, AR 4274 fired off an X1.8 solar flare, the first X-class outburst since June. This solar flare was not aimed at the Earth, but the sunspot cluster erupted in three more flares while crossing the central meridian of the Sun, all of which were aimed straight at the Earth.
AR 4374 produced an X 1.7 flare on 09 November, followed by a long-duration X1.2 flare on 10 November, and then an X5.1 flare on 11 November. This last flare was the strongest solar flare of the year, as well as the sixth-strongest solar flare in the ongoing 11 year solar cycle. The coronal mass ejections (CMEs) associated with these solar flares washed over the Earth, with the second moving fast enough to catch up to the first, resulting in a severe geomagnetic storm. AR 4274 is expected to rotate out of view of the Earth between 16 and 17 November.
Space Weather Foreacst
There is uncertainty on the modelling of the CME from the 14 November eruption. Minor geomagnetic storming is possible in combination with the influence of a coronal hole high speed stream (CH HSS) becoming geoeffective. According to the forecast by the SWPC, “Mostly quiet to unsettled levels are expected for 16 Nov. However, if the shock from the CME associated with the X4 flare from 14 Nov does impact Earth, and our timing is correct, brief enhancements could be seen during the first half of 16 Nov prompting possible G1 (Minor) storm conditions.” According to the latest forecast by the SIDC, “Over the next 24 hours, conditions should range between quiet and unsettled. A glancing blow from the coronal mass ejection (SIDC CME 601) early on 16 November could lift activity to active and minor storm levels, followed around midday by high-speed streams from SIDC Coronal Hole 126 (mid-latitude, negative polarity) that may prolong active to minor strom conditions with a chance of isolated storm intervals.”