Summary and Forecast
Solar Summary
(last updated 26 May 2026 23:30 UT)
Activity 26 May: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 26 May: 141/95
Solar Forecast
(last updated 26 May 2026 23:30 UT)
27 May 28 May 29 May Activity R0, chance of R1 R0-R1 R0-R1 Fadeouts Possible Possible Possible 10.7cm/SSN 145/99 150/105 145/99 COMMENT: Solar flare activity on UT day 26-May was at the R0 level, with the largest flare a C9.7 flare at 26/1238UT. There are currently nine numbered sunspot regions on the visible solar disk and two unnumbered regions. Active region 4451 was responsible for the largest flare of the UT day. 4446 was the only numbered active region to show spot development over the UT day, all other numbered regions are either stable or in decay. Two unnumbered regions have developed on the solar disk, with beta magnetic characteristics. One is at N05W06 and the other is at N08W48. No regions currently visible on the solar disk are particularly large or magnetically complex. Solar flare activity is forecast to be at the R0 level, with a chance of R1 on 27-May. This is forecast to rise to R0-R1 over 28-29 May as potentially flare-active regions on the far side of the disk, detected by Solar Orbiter, rotate onto the front side of the disk. Solar radiation storm conditions were at the S1 level on 26-May due to a large and fast far side Coronal Mass Ejection. Solar radiation storm conditions are expected to be at the S0 level over 27-29 May, with a chance of S1 on 27-May due to currently elevated high energy proton conditions. No geoeffective CMEs have been observed on 26-May. A large and fast partial halo CME, directed to the northwest, was observed from 25/2224UT. This CME is associated with coronal movement behind the northwestern limb, visible in GOES SUVI and SDO imagery from 25/2203UT. This CME is considered a far side event and not geoeffective. A slow, south directed CME is visible from 26/1000UT in SOHO and STEREO-A. This CME is considered a far side event and not geoeffective. The solar wind speed was largely steady over the UT day 25-Mar with a jump observed at around 26/1850UT, possibly due to a glancing CME impact. The wind speed mostly ranged between 360 and 460 m/s . The wind speed is currently at around 420 km/s. The interplanetary magnetic field strength (IMF, Bt) peaked at 10 nT during the UT day, with the north-south component (Bz) ranging between -7 and +8 nT. The solar wind speed is expected to remain at moderate levels over 27-29 May, with the possibility of mild enhancements due to small coronal holes approaching a geoeffective position.
Solar Activity levels are explained in the SWS Solar Terrestrial Glossary.
