Daily bulletin on solar and geomagnetic activity from the SIDC

Существующий: 2026 Apr 03 1309 UTC

SIDC Forecast

Солнечные вспышки

M-class flares expected (probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Солнечные протоны

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
03 Apr 2026	137	024
04 Apr 2026	132	019
05 Apr 2026	127	017

Solar Active Regions and flaring

Solar Active Regions and flaring: Solar flaring activity was moderate over the past 24 hours, with three M-class flares observed. The largest event was an M3.5 flare (SIDC Flare 7316), peaking on 02 April at 18:15 UTC, originating from SIDC Sunspot Group 835 (NOAA Active Region 4404). Two additional M1.3 flares were recorded from SIDC Sunspot Group 838 (NOAA Active Region 4409), peaking on 03 April at 07:56 UTC and 12:50 UTC, respectively. Numerous C-class flares were also observed, with sustained activity primarily originating from SIDC Sunspot Group 838 (NOAA Active Region 4409). A total of eight numbered sunspot groups were present on the solar disk. Most regions exhibited simple Alpha or Beta magnetic configurations. SIDC Sunspot Group 838 (NOAA Active Region 4409), currently located near N02E08, maintained a Beta-Gamma magnetic configuration and showed continued activity, remaining the dominant flaring region on the disk. SIDC Sunspot Group 835 (NOAA Active Region 4404) also contributed to significant activity despite ongoing decay. Solar flaring activity is expected to remain moderate over the next 24 hours, with C-class flares expected and M-class flares likely, primarily from SIDC Sunspot Group 838 (NOAA Active Region 4409).

Выбросы корональной массы

No Earth-directed coronal mass ejections were detected in available coronagraph imagery over the past 24 hours.

Корональные отверстия

SIDC Coronal Hole 149, an equatorial coronal hole with negative polarity, is now well positioned on the western side of the solar disk after crossing the central meridian on 30 March. Its associated high- speed solar wind stream is currently influencing near-Earth solar wind conditions. SIDC Coronal Hole 142, a returning mid- to high-latitude coronal hole with negative polarity, reached the central meridian today on 03 April.

Солнечный ветер

Solar wind parameters remained at enhanced levels over the past 24 hours due to the ongoing influence of a high-speed solar wind stream (HSS) originating from SIDC Coronal Hole 149, an equatorial coronal hole with negative polarity, which crossed the central meridian on 30 March. Solar wind speed was elevated, ranging between approximately 600 and 730 km/s. The interplanetary magnetic field (IMF) was moderately to strongly enhanced, with the total IMF (Bt) reaching up to about 14 nT. The IMF Bz component showed continued variability, with recurrent southward intervals reaching approximately -11 nT. These conditions are consistent with sustained HSS influence following the earlier ICME passage. Solar wind conditions are expected to remain enhanced over the next 24 hours, with continued high-speed stream influence and fluctuating IMF conditions.

Geomagnetism

Geomagnetic conditions ranged from active to Moderate Storm levels over the past 24 hours. The global NOAA Kp index reached up to 6, while the local K index (Belgium) reached up to K=5 (Minor Storm levels). The geomagnetic activity was driven by the high-speed solar wind stream associated with SIDC Coronal Hole 149, combined with sustained periods of southward IMF (negative Bz). Geomagnetic conditions are expected to remain unsettled to active, with possible isolated storm intervals over the next 24 hours, depending on the persistence and orientation of the IMF Bz component.

Proton flux levels

The greater than 10 MeV proton flux showed a gradual increase over the past 24 hours but remained below the event threshold (10 pfu). This increase is also observed in STEREO-A measurements, suggesting a likely far-sided solar event as the source. The greater than 10 MeV proton flux is expected to remain below or near the 10 pfu level over the next 24 hours, although further enhancements cannot be excluded.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux increased from low to moderate levels over the past 24 hours, with values approaching and locally exceeding the high flux threshold. This increase follows the earlier depletion associated with geomagnetic storm conditions and is consistent with the ongoing influence of the high-speed solar wind stream. The 24-hour fluence remained at normal to moderate levels. Electron fluxes are expected to increase further and may reach high levels over the next 24–48 hours due to continued high-speed solar wind stream conditions associated with SIDC Coronal Hole 149. The fluence is expected to increase accordingly.

Today's estimated international sunspot number (ISN): 126, based on 10 stations.

Solar indices for 02 Apr 2026

Wolf number Catania	111
10cm solar flux	140
AK Chambon La Forêt	046
AK Wingst	035
Estimated Ap	041
Estimated international sunspot number	150 - Based on 14 stations

Noticeable events summary

Provided by the Solar Influences Data analysis Center© - SIDC - Processed by SpaceWeatherLive