Summary and Forecast

Solar Summary

(last updated 01 Oct 2026 23:30 UT)

Activity 01 Oct: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 01 Oct: 92/37

Solar Forecast

(last updated 01 Oct 2026 23:30 UT)

02 Oct 03 Oct 04 Oct Activity R0 R0 R0 Fadeouts None expected None expected None expected 10.7cm/SSN 92/37 92/37 90/34 COMMENT: Solar flare activity was at the R0 level on UT day 01-Oct, with a single C-class flare observed. There are currently three active sunspot regions on the visible disk, with Active Region (AR) 4535 (N10W68, beta) being the largest. The centre of this region has remained stable, while mild decay of the trailer spots has been seen over the past 24 hours. AR 4544 (S09W38, beta) has largely decayed, but still remains slightly visible. A new, unnumbered region has emerged (N20E65, beta) over the 01-Oct, Solar flare activity is forecast to remain at the R0 level through the period 02-04 Oct. S0 solar radiation storm conditions were observed throughout 01-Oct, with S0 conditions forecast over 02-04 Oct. A weak Coronal mass ejection (CME) from a C8.6 flare was first observed 0238UT on SDO/AIA 304. Modelling of this event suggests that the bulk of this eruption will pass ahead and above the Earth. However, part of this event is expected to impact Earth, with a glancing CME arrival at Earth forecast on 02-Oct at 1800UT +/-10 hours. Another weak CME was observed following a C-class flare from AR 4535, first visible on LASCO at 0312UT on the 30-Sep. This is anticipated to arrive late on the 03-Oct or early on the 04-Oct as a glancing blow. The solar wind environment was at background levels throughout 01-Oct, with the solar wind speed remaining between 270 and 310km/s, and is currently at 300km/s. The interplanetary magnetic field strength (IMF, Bt) saw a minor increase in strength throughout the UT day, peaking at 7 nT, with the north-south component (Bz) ranging between -5 and +6 nT. The solar wind is speed expected to rise on the 02-Oct, due to the glancing impact of a CME first observed on the 28-Sep. Speeds are expected to decrease throughout the 03-Oct. They will then increase again throughout the 04-Oct as a second CME glances Earth, in combination with the Earth encountering a new coronal hole high speed wind stream.

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