Third M-class solar flare of the day erupts from Region 2403: Long duration M1.1


At 20:34 UTC on August 21, Region 2403 erupted with its third M-class solar flare of the day. The event started at 19:10, peaked at 20:34 as M1.1 and ended at 20:50 UTC.

This was a long duration event. However, there were no recorded radio signatures that would suggest a Coronal Mass Ejection (CME) was generated. 

Region 2403 has Beta-Gamma magnetic configuration, it's rotating into a more geoeffective position, and is capable of producing strong eruptions on Sun. CMEs produced by this region in the days ahead could be directed toward Earth.

1st M-class of the day: M1.2 at 02:18 UTC. 2nd: M1.4 at 09:48 UTC.

The M1.2 event was the first M-class solar flare since July 6, 2015.


There are currently 3 numbered sunspot regions on the Earth side of the Sun.

Region 2403 exhibited slight growth in its leader and intermediate spots yesterday, with the majority of the growth in the leader spot area. The region continued to develop today, showing both consolidation and growth in both the leader and trailer spot.

Region 2401 was mostly inactive, and exhibited slight decay in its trailer spots area yesterday. It rapidly decayed today.

Region 2404 remains mostly simple and inactive with a slight decay.

Image credit: ESA / PROBA2/SWAP.

2401 – Beta
2403 – Beta-Gamma
2404 – Beta


Solar activity is expected to be low, with a slight chance for M-Class (R1-R2, Minor-Moderate) activity over the next 3 days (August 21 to 23), SWPC said in their Forecast Discussion issued 12:30 UTC on August 21.

The greater than 2 MeV electron flux is expected to be at moderate to high levels, with a chance for very high levels, over the next three days. The greater than 10 MeV proton flux is expected to remain at background levels (Below S1-Minor). 

The solar wind environment is expected to remain slightly disturbed on August 21 and 22 as the positive polarity CH in the north remains in a potentially geoeffective position.

Early on August 23, a recurrent, equatorial, positive polarity CH is expected to further influence the solar wind environment, enhancing the wind speed, mag field, temperature, and density. G1 – Minor geomagnetic storm levels are expected as a result.

Featured image: NASA SDO/AIA 304 at 20:34 UTC on August 21, 2015 – M1.1 solar flare.

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