Viewing archive of Wednesday, 23 April 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Apr 23 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
23 Apr 2025	163	007
24 Apr 2025	165	007
25 Apr 2025	167	016

Solar Active Regions and flaring

A total of 11 numbered sunspot groups were identified on the disk over the past 24 hours. Only C-class flaring was observed. The largest flare was a C2.6 flare (SIDC Flare 4183) peaking on April 22 at 18:57 UTC, which was produced by SIDC Sunspot Group 473 (NOAA Active Region 4062). 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

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

The solar wind speed at the Earth is returning to low values with a vanishing influence of the high speed solar wind stream from the large positive polarity coronal hole in the southern hemisphere (SIDC Coronal Hole 104). The solar wind speed has decreased to 460 km/s, with an interplanetary magnetic field around 5 nT. We expect slow solar wind conditions for the next 24 hours. After that, we may see again an increase in solar wind speed, due to the irregular shape of the same coronal hole.

Geomagnetism

Geomagnetic conditions have been quiet to unsettled both locally and at planetary levels (K_Bel and Kp up to 3). Similar 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 and 19 was below the threshold over the past 24 hours. 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. 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): 152, based on 12 stations.

Solar indices for 22 Apr 2025

Wolf number Catania	///
10cm solar flux	163
AK Chambon La Forêt	016
AK Wingst	015
Estimated Ap	015
Estimated international sunspot number	174 - Based on 32 stations

Noticeable events summary

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

All times in UTC

<< Go to daily overview page