Summary and Forecast

Solar Summary

(last updated 04 Jun 2026 23:31 UT)

Activity 04 Jun: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 04 Jun: 148/102

Solar Forecast

(last updated 04 Jun 2026 23:31 UT)

05 Jun 06 Jun 07 Jun Activity R2, chance R3 R2, chance R3 R2, chance R3 Fadeouts Probable Probable Probable 10.7cm/SSN 145/99 143/97 140/94 COMMENT: Solar flare activity on UT day 04-Jun was at the R0 level with several low-level C-class flares observed. There are currently eight numbered active regions visible on the solar disk and one unnumbered region. Active region (AR) 4455 (N15W31, beta-gamma) is the largest and most magnetically complex region on the disk and has exhibited slight spot development over the UT day. Regions 4458 (S04W20, beta), 4459 (N14E22, beta), 4460 (S23W85, beta) and 4462 (N19E45, beta) all have shown some spot growth over the UT day. All other regions are either stable or in decay. Solar flare activity is expected to be at R2 level over 05-07 Jun, with a chance of R3. S0 solar radiation storm conditions were observed on UT day 04-Jun. S0 solar radiation storm conditions are expected over 05-07 Jun. No Earth-directed coronal mass ejections (CMEs) have been observed. A narrow east-directed CME was observed, visible in LASCO C2 coronagraph imagery from 04/0424UT. Modelling indicates this CME does not contain an Earth-directed component. The solar wind speed on UT day 04-Jun was stable, ranging from 385 to 445 km/s and is currently near 420 km/s. The peak total interplanetary magnetic field strength (IMF, Bt) was 11 nT and the north-south IMF component (Bz) range was -9 to +6 nT. The solar wind speed is expected to increase on 05-Jun due to the anticipated arrival of three CMEs first observed on 03-Jun then remain elevated over 06-07 Jun.

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