Viewing archive of Thursday, 24 April 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Apr 24 1231 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
24 Apr 2025	167	013
25 Apr 2025	169	016
26 Apr 2025	171	007

Solar Active Regions and flaring

A total of 14 numbered sunspot groups were identified on the disk over the past 24 hours. Only C-class flaring was observed int he last 24 hours. The most complex sunspot group is SIDC Sunspot Group 482 (NOAA Active Region 4070) currently located at S12E24, with a Beta-Gamma magnetic configurations. The largest flare was a C3.8 flare (SIDC Flare 4191) peaking on April 24 at 00:28 UTC, which was produced by SIDC Sunspot Group 474 (NOAA Active Region 4064). Solar flaring activity is expected to be low over the next 24 hours, with C-class flares expected and M-class flares possible.

Coronal mass ejections

A CME was seen first at 08:00 UTC on April 23 by LASCO C2, erupting towards the west, with angular width around 70 degrees. This CME is backsided, not expected to arrive to the Earth. No Earth- directed CMEs were observed in the available coronagraph imagery in the last 24 hours.

Coronal holes

There is a large positive polarity coronal hole (SIDC Coronal Hole 104) covering a large area of the southern hemisphere.

Solar wind

A shock was observed in the solar wind at L1 at 06:12 UT, the interplanetary magnetic field jumped from 8 to 15 nT and the solar wind speed from 460 to 640 km/s. The driver of the shock may be a CME that left the Sun on 22 April at 08:12 UT from SIDC Sunspot Group 476 (NOAA Active Region 4065), and is currently passing south of the Earth. The solar wind speed is around 500 km/s, with an interplanetary magnetic field around 10 nT. We expect a return to slow solar wind conditions for the next 24 hours. After that, we may again see an increase in solar wind speed, due to the irregular shape of the SIDC Coronal Hole 104.

Geomagnetism

Geomagnetic conditions have reached active levels globally (Kp up to 4) and unsettled locally (K_Bel up to 3). Unsettled to active conditions can be expected in the next 24 hours.

Proton flux levels

The greater than 10 MeV proton flux was below the threshold level over the past 24 hours. It is expected to remain below the threshold level over the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 was below the threshold over the past 24 hours and slightly above it in GOES 19 (between 19:00 and 23:00 UTC on 23 April). The greater than 2 MeV electron flux is expected to increase over the next 24 hours, due to the influence of the high speed stream in the previous days. The 24-hour electron fluence is presently at normal levels, it may increase over the next 24 hours.

Today's estimated international sunspot number (ISN): 198, based on 06 stations.

Solar indices for 23 Apr 2025

Wolf number Catania	124
10cm solar flux	167
AK Chambon La Forêt	011
AK Wingst	006
Estimated Ap	006
Estimated international sunspot number	158 - Based on 21 stations

Noticeable events summary

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

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