Summary and Forecast

Solar Summary

(last updated 20 Apr 2026 23:30 UT)

Activity 20 Apr: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 20 Apr: 105/54

Solar Forecast

(last updated 20 Apr 2026 23:30 UT)

21 Apr 22 Apr 23 Apr Activity R0 R0 R0 Fadeouts None expected None expected None expected 10.7cm/SSN 110/60 120/72 120/72 COMMENT: Solar activity on UT day 20-Apr was R0, with no solar flares. There are currently two numbered sunspot regions on the solar disk. Active region (AR) 4415 (S18W89, alpha) is no longer visible but appeared stable, and 4419 (N15W22, beta) went through a brief growth phase following by decay. Solar activity is expected to be R0 over 21-23 Apr. No CMEs were observed on UT day 20-Apr. S0 solar radiation storm conditions were observed on UT day 20-Apr. S0 solar radiation storm conditions are expected over 21-23 Apr. The solar wind environment on UT day 20-Apr continued to be elevated due to the effects of a coronal hole. The solar wind speed ranged from 400 to near 550 km/s. The peak total interplanetary field strength (IMF, Bt) was 10 nT and the north-south IMF component range (Bz) was +5 to -8 nT. Periods of southward Bz were observed from 0555-1010 UT and again at 1535-1900 UT. The solar wind environment is expected to remain elevated on UT day 21-Apr before beginning to decline to near background levels.

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