Daily bulletin on solar and geomagnetic activity from the SIDC

Emesso: 2025 Apr 03 1231 UTC

SIDC Forecast

Brillamenti solari

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

Geomagnetism

Active conditions expected (A>=20 or K=4)

Protoni solari

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

	10cm flux	Ap
03 Apr 2025	178	024
04 Apr 2025	176	024
05 Apr 2025	174	031

Solar Active Regions and flaring

Solar flaring activity was low, with only C-class flares recorded over the past 24 hours. The largest flare was a C3.4 flare (SIDC Flare 4021), peaking at 09:13 UTC on April 3, associated with SIDC Sunspot Group 458 (NOAA Active Region 4045; alpha). There are currently eight numbered active regions visible on the solar disk. SIDC Sunspot Group 461 (NOAA Active Region 4048; beta-gamma), which remains one of the more magnetically complex active regions on the disk, was the main driver of the flaring activity observed over the past 24 hours together with SIDC Sunspot Group 458 (NOAA Active Region 4045; alpha). Low flaring activity was also produced by SIDC Sunspot Group 464 (NOAA Active Region 4050; beta) and SIDC Sunspot Group 455 (NOAA Active Region 4043; beta). Solar flaring activity is expected to be moderate over the next 24 hours, with M-class flares likely and a small chance for X-class flares.

Espulsioni di massa coronale

No Earth-directed Coronal Mass Ejections (CMEs) have been detected in the available coronagraph images.

Vento solare

Over the past 24 hours, solar wind parameters (ACE and DSCOVR) reflected mild ICME influence. The interplanetary magnetic field reached values of up to 12 nT, and the solar wind speed ranged between 400 km/s and 450 km/s. Solar wind conditions are expected to remain slightly elevated over the next 24 hours, with a potential weak enhancement on April 4 - April 5 due to the possible arrival of a high-speed stream from a negative polarity coronal hole that began crossing the central meridian on April 1.

Geomagnetism

Geomagnetic conditions over the past 24 hours reached active levels globally (NOAA Kp: 4). Locally only quiet to unsettled (K-Bel=2-3) conditions were observed over Belgium. Mostly quiet to unsettled conditions are expected over the next few days, with a chance of isolated active periods on April 3 due to ongoing ICME influence. From April 4, active conditions are expected, with a possible isolated minor storm interval in response to the arrival of the high-speed stream.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux was slightly elevated, remaining well below radiation storm levels. The proton flux is expected to gradually return to nominal levels over the next few days, with a chance of exceeding minor storm levels if any high-energy flares or eruptions occur.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux, as measured by GOES-18, was below the 1000 pfu threshold and is expected to remain so over the next 24 hours. The 24-hour electron fluence was at normal to moderate levels and is expected to remain at normal levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 159, based on 23 stations.

Solar indices for 02 Apr 2025

Wolf number Catania	181
10cm solar flux	180
AK Chambon La Forêt	028
AK Wingst	018
Estimated Ap	021
Estimated international sunspot number	136 - Based on 20 stations

Noticeable events summary

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