4th M-class flare: M1.2 from Region 2403 peaks at 06:49 UTC on August 22 producing a CME


Region 2403 erupted with its fourth M-class solar flare at 06:49 UTC on August 22, 2015. The latest event started at 06:39, peaked at 06:49 as M1.2, and ended at 06:59 UTC. Radio signatures indicate a Coronal Mass Ejection (CME) was produced.

A Type II Radio Emission with estimated velocity of 1 149 km/s was observed starting 06:50 UTC. Additionally, a Type IV emission was observed starting at 06:56 UTC. Type IV emissions occur in association with major eruptions on the Sun and are typically associated with strong CMEs and solar radiation storms.

The responsible region, AR 2043 (Beta-Gamma), is still in a growing phase with a majority of the increase located within its intermediate area. It is now more than 90 000 km (55 920 miles) wide and poses a threat for both M- and X-class solar flares. It is moving toward the center of the Sun, into a perfect geoeffective position. Should it produce more CMEs over the coming days, they will most likely be Earth-directed, or have Earth-directed components.

1st M-class: M1.2 at 02:18 UTC on August 21; 2nd: M1.4 at 09:48 UTC on August 21; 3rd: M1.1 at 20:34 UTC on August 21.

John Ashley photographed Region 2403 through the smokey atmosphere of Kila, Montana, on August 20th:

Taken by John Ashley on August 20, 2015 @ Kila, Montana (via SpaceWeather).


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

Region 2403 is still in a growing phase with the majority of the increase located within its intermediate area.

Slight growth was observed in Region 2404 while Region 2401 continues to decay.

Sunspots on August 22, 2015. Image credit: NASA SDO/HMI.

2401 – Alpha
2403 – Beta-Gamma
2404 – Beta


Solar activity is expected to be at low levels with a chance for further M-class (R1-R2, Minor-Moderate) flares and a slight chance for X-class (R3-Strong or greater) flaring for the next three days (August 22 – 24) due to flare potential from Region 2403.

The greater than 2 MeV electron flux is expected to be at moderate to high levels. The greater than 10 MeV proton flux is expected to remain at background levels (Below S1-Minor).

Solar wind parameters are expected to continue at slightly enhanced levels through early August 23 when a positive polarity, equatorial coronal hole high speed stream (CH HSS) is expected to move into geoeffective position. Solar wind speeds in excess of 500 km/s are expected with the onset along with an increase in magnetic field intensity. Activity is expected to persist into August 24.

The geomagnetic field is quiet and is expected to be at quiet to unsettled levels through early August 22 and on August 23 when the onset of another positive polarity CH HSS is expected to cause unsettled to active conditions with G1 (Minor) storm periods likely. Quiet to active conditions are expected to persist through August 24, according to SWPC's Forecast Discussion issued 00:30 UTC on August 22, 2015.

Update #1

A fifth, and strongest so far, M-class solar flare was produced at 13:23 UTC on August 22 by Region 2403. The event started at 13:17, peaked at 13:23 as M2.2, and ended at 13:29 UTC. 

The flare was impulsive in nature. There were no radio signatures that would suggest a CME was produced.

Update #2

A sixth M-class solar flare was produced by Region 2403 at 21:24 UTC on August 22, 2015. The event started at 21:19, peaked at 21:24 as M3.5, and ended at 21:28 UTC. WSA/ENLIL analysis suggests the CME to arrive early on August 24.

Featured image credit: John Ashley, taken on August 20, 2015 @ Kila, Montana (via SpaceWeather). 

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