Summary and Forecast

Solar Summary

(last updated 04 Aug 2026 23:30 UT)

Activity 04 Aug: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 04 Aug: 118/70

Solar Forecast

(last updated 04 Aug 2026 23:30 UT)

05 Aug 06 Aug 07 Aug Activity R0, chance of R1 R0, chance of R1 R0, chance of R1 Fadeouts None expected None expected None expected 10.7cm/SSN 115/66 110/60 110/60 COMMENT: Solar flare activity on UT day 04-Aug was at the R0 level, with no significant flares observed. There are currently six sunspot regions on the visible solar disk, with Active Region (AR) 4498 (N14W28, beta) being the largest. This region has remained stable over the past UT day. AR 4502 (S11W23, beta) has shown mild growth over the same period. A new region, AR 4503 (S17E68), has recently rotated over the eastern limb, with a magnetic classification currently dominated by limb foreshortening. All other regions are either stable or in decay. Solar flare activity is forecast to remain at the R0 level over 05-07 Aug, with a chance of R1 due to the presence of region 4498. Solar radiation storm conditions were at the S0 level throughout 04-Aug, and are forecast to remain at the S0 level over 05-07 Aug. A coronal mass ejection (CME) was observed in Stereo-A from 04/1323UT, associated with dimming observed on the solar disk in SDO/AIA 211A from 04/1230UT. Initial modelling of this event has suggested a glancing impact is possible at Earth at 08/0800UT +/- 12 hours. However, further imaging is required to better constrain the CME trajectory. Additional analysis of the three CMEs first observed on 03-Aug has confirmed that a combined minor glancing impact is forecast to arrive at Earth at 04/0700UT +/- 10 hours. The solar wind speed was at a constant light to moderate level over 04-Aug, broadly ranging between 360-440 km/s throughout the UT day. The interplanetary magnetic field strength (IMF, Bt) decreased during 04-Aug, peaking at 11 nT early in the UT day, before declining after 04/0919UT. The north-south component (Bz) of the IMF ranged between -10 and +9 nT over the UT day, with extended periods of significant southward Bz between 03/2358UT and 04/0217UT, as well as between 04/0432UT and 04/0807UT. The solar wind is expected to remain near background values over 05-06 Aug, before rising on 07-Aug due to the glancing impacts of the CMEs first observed on 03-Aug.

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