Daily bulletin on solar and geomagnetic activity from the SIDC

Emesso: 2025 Apr 01 1231 UTC

SIDC Forecast

Brillamenti solari

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

Geomagnetism

Quiet (A<20 and K<4)

Protoni solari

Proton event in progress (>10 MeV)

	10cm flux	Ap
01 Apr 2025	173	004
02 Apr 2025	173	017
03 Apr 2025	173	011

Solar Active Regions and flaring

Solar flaring activity was high, with one M-class flare and multiple C-class flares recorded over the past 24 hours. The largest flare was an M5.6 flare (SIDC Flare 3994) peaking at 06:46 UTC on April 01, associated with SIDC Sunspot Group 459 (NOAA Active Region 4046, beta-gamma). There are currently eight numbered active regions visible on the solar disk. SIDC Sunspot Group 461 (NOAA Active Region 4048; beta-gamma-delta) that has grown in size and remains magnetically most complex active region on the disk, was the main driver of the flaring activity observed over the past 24 hours. Low flaring activity was also produced by SIDC Sunspot Group 460 (NOAA Active Region 4047; beta). Other regions on the disc have simple configuration of their photospheric magnetic field (alpha and beta) and did not show any significant flaring activity. Solar flaring activity is expected to be moderate to high over the next 24 hours, with M-class flares very 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.

Fori coronali

A low-latitude, negative polarity coronal hole began to cross the central meridian on April 1. The associated high-speed stream is expected to arrive at Earth starting April 4.

Vento solare

Over the past 24 hours, the solar wind parameters (ACE and DSCOVR) reflected mild ICME influence. The total interplanetary magnetic field reached values up to 11 nT. The solar wind speed ranged between 400 km/s and 500 km/s. A gradual transition to slow solar wind conditions is expected for the next 24 hours, with a chance of a weak enhancement on April 1 - April 2 due to the possible arrival of a high-speed stream from a positive polarity coronal hole, that started to cross the central meridian on March 25.

Geomagnetism

Geomagnetic conditions over the past 24 hours were quiet both globally and locally over Belgium (NOAA Kp: 1-2, K-Bel:1-2). Mostly quiet to unsettled conditions are expected over the next days, with a chance of isolated active or minor storm periods on April 1-2 due to possible high- speed stream arrival.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux exceeded the 100 pfu threshold, reaching a maximum value of 147 pfu as measured by GOES-18 at 04:25 UTC on April 1. The proton flux is currently above the 10 pfu threshold and is expected to remain elevated over the coming days.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux, as measured by GOES-18, was above the 1000 pfu threshold between 01:35 UTC on March 31 and 05:15 UTC on April 1. There is a chance that the greater than 2 MeV electron flux will exceed this level again in the coming days. The 24-hour electron fluence was at moderate levels and is expected to remain so over the next 24 hours.

Today's estimated international sunspot number (ISN): 157, based on 19 stations.

Solar indices for 31 Mar 2025

Wolf number Catania	///
10cm solar flux	172
AK Chambon La Forêt	013
AK Wingst	005
Estimated Ap	006
Estimated international sunspot number	142 - Based on 34 stations

Noticeable events summary

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