Summary and Forecast
Solar Summary
(last updated 25 Aug 2026 23:30 UT)
Activity 25 Aug: R2 Flares Max Fadeout Freq. Sectors M1.9 0126UT possible lower West Pacific M1.0 0403UT possible lower E. Asia/Aust. M1.8 0640UT possible lower Mid East/Indian M6.9 1002UT probable lower European Observed 10.7 cm flux/Equivalent Sunspot Number for 25 Aug: 132/86
Solar Forecast
(last updated 25 Aug 2026 23:30 UT)
26 Aug 27 Aug 28 Aug Activity R1, chance of R2 R1, chance of R2 R1, chance of R2 Fadeouts Possible Possible Possible 10.7cm/SSN 135/89 133/87 130/84 COMMENT: Solar flare activity on UT day 25-Aug was at the R2 level due to an M6.9 flare at 25/1002UT produced by Active Region (AR) 4513 (N04E05, beta-gamma-delta). This region also produced three additional flares at the R1 level over the UT day. There are currently four numbered sunspot regions visible on the solar disk. Region 4513 is the most magnetically complex region on the disk and has shown some decay in its intermediate spots over the past 24 hours. AR 4517 (N09W12, beta) has exhibited spot development in its intermediate spots. AR 4516 (N04E05, beta) has shown growth in its leader spots, whilst its trailer spot has decayed. AR 4515 (S08E13, alpha) is simple and stable. Solar flare activity is expected to be at the R1 level over 26-28 Aug, with a chance of R2 due to the observed flare activity and magnetic complexity of AR 4513. S0 solar radiation storm conditions were observed on UT day 25-Aug, with the proton flux gradually declining over the UT day. S0 solar radiation storm conditions are expected over 26-28 Aug, with a chance of S1 due to the current mildly elevated proton flux conditions. An east-directed coronal mass ejection (CME) was observed, visible in STEREO-A coronagraph imagery from 25/1038UT. This CME is considered to be associated with the aforementioned M6.9 flare from AR 4513. A filament eruption was observed, visible in H-alpha imagery from 1236UT near S01E20. A subsequent associated narrow CME was observed in STEREO-A at 25/1253UT. Modelling of the above CMEs indicates the bulk of the ejecta will miss Earth. However, the flank of the disturbance is expected to produce a glancing arrival at Earth, with an estimated arrival time of 0200UT +/- 10 hours on UT day 28-Aug. No other Earth-directed CMEs have been observed. The solar wind speed on UT day 25-Aug declined, ranging between 355 and 320 km/s, and is currently near 325 km/s. The peak total interplanetary magnetic field strength (IMF, Bt) was 7 nT and the north-south IMF component (Bz) range was -1 to +4 nT. The solar wind speed is expected to remain at background levels on 26-Aug, then increase on 27-Aug due to coronal hole high speed wind stream effects from a southern hemisphere coronal hole. A further increase is expected on 28-Aug due to the arrival of two CMEs first observed on 25-Aug.
Solar Activity levels are explained in the SWS Solar Terrestrial Glossary.
