Summary and Forecast
Solar Summary
(last updated 25 Apr 2026 23:31 UT)
Activity 25 Apr: R1 Flares Max Fadeout Freq. Sectors M1.3 0759UT possible lower Mid East/Indian M1.1 1430UT possible lower South American/ Atlantic Observed 10.7 cm flux/Equivalent Sunspot Number for 25 Apr: 148/na
Solar Forecast
(last updated 25 Apr 2026 23:31 UT)
26 Apr 27 Apr 28 Apr Activity R1-R2 R1-R2 R1-R2 Fadeouts Possible Possible Possible 10.7cm/SSN 148/102 145/99 145/99 COMMENT: Solar flare activity on UT day 25-Apr was at the R1 level due to two M-class flares, the largest of which was an M1.3 at 25/0759UT produced by active region (AR) 4423 (S07E22, beta-delta). There are currently seven numbered sunspot regions visible on the solar disk. AR 4420 (N16E02, beta-gamma-delta) is the largest and most magnetically complex region on the disk. This region has shown spot development in its intermediate spots including the development of a delta spot, whilst its trailer spots have exhibited some decay over the UT day. Regions 4424 (N17E33, beta) and 4425 (N05E65, beta) have both exhibited spot growth in their trailer spots. All other sunspot regions are either stable or in decay. Solar flare activity is expected to be at R1-R2 levels over 26-28 Apr due to the magnetic complexity of regions 4420, 4423 and possible beyond-the-limb flares from region 4419. S0 solar proton conditions were observed on UT day 25-Apr. S0 solar proton conditions are expected over 26-28 Apr, with a chance of S1. No Earth-directed coronal mass ejections (CMEs) have been observed. The solar wind speed on UT day 25-Apr mildly increased, ranging from 360 to 445 km/s and is currently near 425 km/s. The peak total interplanetary magnetic field strength (IMF, Bt) was 12 nT and the north-south IMF component (Bz) range was -10 to +8 nT. A period of sustained southward IMF conditions was observed over the interval 25/2002-2210UT. The solar wind speed is expected to increase on 26-Apr due to the arrival of a CME first observed on 23-Apr. The solar wind is expected to decrease over 27-28 Apr.
Solar Activity levels are explained in the SWS Solar Terrestrial Glossary.
