Summary and Forecast
Solar Summary
(last updated 27 Apr 2026 23:30 UT)
Activity 27 Apr: R1 Flares Max Fadeout Freq. Sectors M6.0 26/2257UT probable lower East Pacific/ North American M1.0 0645UT possible lower Mid East/Indian Observed 10.7 cm flux/Equivalent Sunspot Number for 27 Apr: 142/96
Solar Forecast
(last updated 27 Apr 2026 23:30 UT)
28 Apr 29 Apr 30 Apr Activity R2, chance of R3 R2, chance of R3 R2, chance of R3 Fadeouts Probable Probable Probable 10.7cm/SSN 145/99 145/99 145/99 COMMENT: Solar flare activity reached the R1 level on UT day 27-Apr, with an M1.0 flare from Active Region (AR) 4425 (N05E38, beta-gamma-delta), peaking at 27/0645UT. This region is the largest of seven regions on the visible solar disk, and has exhibited some growth over the last 24 hours. AR 4424 (N17E06, beta-gamma) has also shown some mild growth and spot separation. Region of interest, AR 4420 (N16W26, beta-gamma-delta), has shown some minor decay. A new unnumbered region appeared at S25E28 and currently has a beta magnetic classification. All other regions are either stable or in decay. Solar flare activity is forecast to be at the R2 level, with a chance of R3 over 28-30 Apr, given the magnetic complexity of flare-active regions 4420 and 4425. S0 solar proton conditions were recorded throughout UT day 27-Apr, with the solar proton flux persisting at background levels. S0 solar proton conditions are forecast for 28-30 Apr. No geoeffective coronal mass ejections (CMEs) have been observed over the last 24 hours in available coronagraph imagery. The solar wind speed was constant throughout UT day 27-Apr, broadly ranging between 420 and 460 km/s. The interplanetary magnetic field strength (IMF, Bt) peaked at 6 nT during the UT day, and the north-south component (Bz) ranged between -3 and +5 nT over the UT day. The solar wind will remain moderate over 28-Apr, before a rise during 29-Apr due to the Earth entering a high speed wind stream from a small equatorial coronal hole. The wind speed will remain elevated on 30-Apr.
Solar Activity levels are explained in the SWS Solar Terrestrial Glossary.
