Summary and Forecast

Solar Summary

(last updated 24 Jul 2025 23:32 UT)

Activity 24 Jul: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 24 Jul: 156/110

Solar Forecast

(last updated 24 Jul 2025 23:32 UT)

25 Jul 26 Jul 27 Jul Activity R0, chance of R1 R0, chance of R1 R0, chance of R1 Fadeouts Possible Possible Possible 10.7cm/SSN 155/109 150/105 155/109 COMMENT: Solar activity on UT day 24-Jul was at the R0 level with several C-class flares. There are currently seven numbered sunspot regions and one unnumbered region visible on the solar disk. AR4153 (S38E35, beta) showed spot growth over the UT day, whilst AR4149 (N16E09, beta-gamma) and AR1455 (S07E62, beta) showed growth in their trailer spots. AR4149 is the largest and most magnetically complex sunspot region on the solar disk, but has yet to produce significant flares. An unnumbered region has emerged on the disk at around S21W45 with beta magnetic complexity. All other regions and either stable or in decay. Solar activity is expected to be at the R0 level, with a chance of R1 over 25-27 Jul. S0 solar radiation storm conditions were observed on UT day 24-Jul. S0 solar radiation storm conditions are expected over 25-27 Jul. No significantly Earth directed CMEs were observed on 24-Jul. A west directed, faint CME is visible in SOHO imagery from 24/0624UT. An associated eruption off the western limb is visible in SDO and GOES SUVI imagery from 24/0527UT at around S25. This CME is not considered geoeffective. A west directed CME is visible in SOHO imagery from 24/1700UT. An associated eruption off the western limb is visible from 24/1618UT in SDO and GOES SUVI imagery at around S12. Modelling of CMEs is difficult due to an outage to STEREO-A, increasing forecast uncertainty. This CME is expected to pass ahead of Earth. The solar wind speed declined slightly on 24-Jul UT day, mostly ranging between 550 km/s and 730 km/s and is currently at around 580 km/s. The peak total interplanetary field strength (IMF, Bt) was 7 nT and the north-south IMF component range (Bz) was +6 to -6 nT. The solar wind speed is expected to remain elevated over 25-Jul, with a gradual decline, due to ongoing coronal hole high speed wind stream effects. An increase in solar wind speed is possible on 26-Jul due to the chance of a glancing impact from a CME first observed on 23-Jul. The solar wind is expected to be in decline on 27-Jul.

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