Summary and Forecast

Solar Summary

(last updated 26 Jul 2026 23:30 UT)

Activity 26 Jul: R1 Flares Max Fadeout Freq. Sectors M3.2 1528UT possible lower South American/ Atlantic Observed 10.7 cm flux/Equivalent Sunspot Number for 26 Jul: 148/102

Solar Forecast

(last updated 26 Jul 2026 23:30 UT)

27 Jul 28 Jul 29 Jul Activity R0-R1 R0, chance of R1 R0, chance of R1 Fadeouts Possible None expected None expected 10.7cm/SSN 150/105 150/105 145/99 COMMENT: Solar flare activity reached the R1 level on UT day 26-Jul with an M3.2 flare peaking at 26/1528UT from Active Region (AR) 4494 (S04E05, beta). This is one of six sunspot regions on the solar disk, and has shown some decay following this flare. Nearby AR 4495 (S02W09, beta) has shown growth over the past UT day. Region 4496 has also shown some mild growth in trailing spots over the same period. All other regions are stable or in decay. Solar flare activity is forecast to be at the R0-R1 level on 27-Jul, due to the past flare activity of several regions on the disk. This is forecast to decline to R0, with a chance of R1 over 28-29 Jul, as a previously flare-active region rotates off the disk and other active regions continue to simplify. S0 solar radiation storm conditions were observed throughout 26-Jul, with S0 conditions forecast over 27-29 Jul. A low-velocity coronal mass ejection (CME) was observed in STEREO-A/COR2, coincident with the aforementioned M3.2 flare. Preliminary modelling suggests this CME will likely pass behind the Earth. However, additional imaging is required in order to confirm if this event contains a geoeffective component. A second CME was observed in SOHO/LASCO from 26/2036UT. While this appears to be a farside event, additional imaging is required to rule out any Earth-directed component. The solar wind speed continued to decline over UT day 26-Jul, as the effects of the previous coronal hole high speed wind stream continued to abate. The solar wind speed began the day at 500 km/s, and is currently at 440-460 km/s. The interplanetary magnetic field strength (IMF, Bt) peaked at 5 nT early in the UT day, with the north-south component (Bz) ranging between -4 and +4 nT over the UT day. The solar wind is forecast to increase on 27-Jul, due to the glancing impact of a CME first observed on 24-Jul. The solar wind speed is then expected to decline over 28-29 Jul, as the effects of this CME pass.

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