Summary and Forecast
Solar Summary
(last updated 15 Apr 2026 23:30 UT)
Activity 15 Apr: R0 Flares: none. Observed 10.7 cm flux/Equivalent Sunspot Number for 15 Apr: 105/54
Solar Forecast
(last updated 15 Apr 2026 23:30 UT)
16 Apr 17 Apr 18 Apr Activity R0 R0 R0 Fadeouts None expected None expected None expected 10.7cm/SSN 110/60 110/60 110/60 COMMENT: Solar flare activity was at the R0 level during UT day 15-Apr. The solar regions currently on the solar disk are small to medium in size. Solar region AR4419 (N13E44, beta) is the largest of the on disk regions and is growing. Solar region AR4416 (N19W53, beta) has shown minor development in intermediate spots and decay in its trailer spots. Solar region AR4415 (S18W21, alpha) is a stable monopole. There are currently three numbered regions on the visible solar disk. A faint solar filament located at approximately S30E10 slowly lifted off the solar disk during the interval 15/0900-1200UT and on disk plasma motion was also evident further to the southeast of this location at S40E40. A broad plasma spray off the northwest solar limb was observed in GOES 304 imagery from 15/1229UT. S0 solar radiation storm conditions were observed on 15-Apr. S0 solar radiation storm conditions are expected for 16-18 Apr. No significantly Earth directed CMEs have been observed. At the start of the UT day a non-Earth directed northeast CME was already in progress that could not be correlated to on disk activity. Southeast directed CMEs were observed in association with the slow filament eruption(s). There appeared to be two events with two speeds as longitude agreement was not possible for the CMEs visible in LASCO and STEREO-A to be considered as the one event. The slow CME event more visible in STEREO-A has been modelled as an Earth miss. The CME event that was more visible is LASCO imagery was faster and is also modelled as an Earth miss. A northwest CME was also observed from 15/1148UT which is considered a far side event associated with the broad northwest limb plasma spray visible in GOES 304. A large isolated coronal hole located in the northeast solar quadrant that extends to the south across the solar equator has started to cross the solar central meridian. The solar wind speed on UT day 15-Apr slightly declined and ranged from 380 to 340 km/s and is currently at 340 km/s. The peak total interplanetary magnetic field strength (IMF, Bt) was 5 nT and the north-south IMF component (Bz) ranged between -5 and +4 nT. The solar wind speed is expected to remain at background levels on 16-Apr. 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 entry into the high speed wind stream.
Solar Activity levels are explained in the SWS Solar Terrestrial Glossary.
