Summary and Forecast

Solar Summary

(last updated 19 Sep 2026 23:30 UT)

Activity 19 Sep: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 19 Sep: 97/44

Solar Forecast

(last updated 19 Sep 2026 23:30 UT)

20 Sep 21 Sep 22 Sep Activity R0 R0, slight chance R1 R0, slight chance R1 Fadeouts None expected None expected None expected 10.7cm/SSN 98/45 98/45 98/45 COMMENT: Solar flare activity on UT day 19-Sep was at the R0 level, with a C3.3 flare peaking at 19/1817UT from the eastern limb being the largest observed. There are currently three unnumbered active sunspot regions on the disk, with two small and magnetically simple regions appearing at N09E05 and S05W37. A third region has rotated onto the disk at S13E86, and appears to exhibit an alpha magnetic classification. Solar flare activity is forecast to be at the R0 level over 20-22 Sep, with a slight chance of R1 over 21-22 Sep, due to activity on the eastern limb suggesting a new active region may rotate onto the front side of the disk in the coming days. S0 solar radiation storm conditions were observed throughout 19-Sep, with S0 conditions forecast for 20-22 Sep. No geoeffective coronal mass ejections (CMEs) were observed over the previous UT day. The solar wind environment was stable over the previous 24 hours, with the solar wind speed ranging between 400 and 440 km/s throughout the UT day. The interplanetary magnetic field strength (IMF, Bt) was also stable, peaking at 7 nT, with the north-south component (Bz) ranging between -5 and +5 nT. The solar wind is forecast to remain at this level over 20-21 Sep, before rising late on 22-Sep as an equatorial coronal hole begins to move into a geoeffective position.

Solar Activity levels are explained in the SWS Solar Terrestrial Glossary.