Summary and Forecast
Solar Summary
(last updated 04 Oct 2026 23:30 UT)
Activity 04 Oct: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 04 Oct: 92/37
Solar Forecast
(last updated 04 Oct 2026 23:30 UT)
05 Oct 06 Oct 07 Oct Activity R0 R0 R0 Fadeouts None expected None expected None expected 10.7cm/SSN 92/37 90/34 90/34 COMMENT: Solar flare activity was at the R0 level on UT day 04-Oct, with no significant flares observed. There are currently six active sunspot regions on the solar surface, with Active Region (AR) 4548 (S11E38, alpha) being the largest. This region has remained stable over the past UT day. Region 4547 (N15W46, beta) has exhibited growth over the same period, but remains overall magnetically simple. Two new regions have appeared on the disk over the past 24 hours at N20W13 and N10E21, appearing to have alpha and beta magnetic classifications respectively. All other regions are either stable or in decay. Solar flare activity is forecast to be at the R0 level over 05-07 Oct. S0 solar radiation storm conditions were observed on 04-Oct, with the solar proton flux at background levels throughout the UT day. S0 solar radiation storm conditions are forecast over 05-07 Oct. No coronal mass ejections were observed in available coronagraph imagery over the previous UT day. The solar wind speed increased over UT day 04-Oct as the Earth connected with a coronal hole high speed wind stream. The solar wind speed began the day at 300 km/s, increasing to reach a maximum speed of 640 km/s at 1800UT. The solar wind speed is currently ranging between 580-610 km/s. The interplanetary magnetic field strength (IMF, Bt) also increased due to the high speed wind stream, reaching a peak of 22 nT, with the north-south component (Bz) ranging between -20 and +14 nT over the UT day. Several periods of extended southward Bz were observed across the UT day, with the largest occurring between 04/0901-1200UT. The solar wind speed is forecast to remain elevated over 05-Oct due to the ongoing high speed wind stream effects, before declining on 06-07 Oct as these effects subside.
Solar Activity levels are explained in the SWS Solar Terrestrial Glossary.
