Summary and Forecast
Solar Summary
(last updated 16 Apr 2026 23:30 UT)
Activity 16 Apr: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 16 Apr: 108/58
Solar Forecast
(last updated 16 Apr 2026 23:30 UT)
17 Apr 18 Apr 19 Apr Activity R0 R0 R0 Fadeouts None expected None expected None expected 10.7cm/SSN 110/60 110/60 108/58 COMMENT: Solar flare activity was at the R0 level during UT day 16-Apr. Solar region AR4419 (N13E31, beta-gamma) has continued to slowly develop and produced several low level C1 flares in the past 24 hours and this medium sized region is currently the largest of the on disk regions. Smaller solar region AR4416 (N19W67, beta) is decaying as it approaches the northwest solar limb. Solar region AR4415 (S18W34, alpha) is a stable monopole. There are currently three numbered regions on the visible solar disk. A new small solar region may soon rotate onto the solar disk at solar latitude N13. Solar flare activity is forecast to be at the R0 level over 17-19 Apr, with a slight chance of an isolated R1 flare from AR4419. S0 solar radiation storm conditions were observed on 16-Apr. S0 solar radiation storm conditions are expected for 17-19 Apr. No Earth directed CMEs have been observed. A westward CME was observed from 15/2348UT and is considered a far side event. A large isolated coronal hole is located across the solar central meridian. The solar wind speed on UT day 16-Apr was light and steady and ranged from 343 to 319 km/s and is currently at 334 km/s. The peak total interplanetary magnetic field strength (IMF, Bt) was 7 nT and the north-south IMF component (Bz) ranged between -4 and +4 nT. A very weak partial shock signature was observed in some of the solar wind parameters at 16/0254UT. An increase in the solar wind speed is expected from late 17-Apr and on 18-Apr from the large coronal hole now crossing the solar central meridian, with possible moderate southward fluctuations of the IMF Bz component prior to and during the Earth's entry into the high speed wind stream.
Solar Activity levels are explained in the SWS Solar Terrestrial Glossary.
