Viewing archive of Monday, 28 April 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Apr 28 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
28 Apr 2025	156	007
29 Apr 2025	154	007
30 Apr 2025	152	007

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with only C-class flares identified. A total of 12 numbered sunspot groups were identified on the disk over the past 24 hours, they all have simple alpha or beta magnetic field configuration. The largest flare was a C2.2 flare (SIDC Flare 4231) peaking on April 28 at 06:02 UTC, which was produced by SIDC Sunspot Group 481 (NOAA Active Region 4069). Solar flaring activity is expected to be low over the next 24 hours, with C-class flares expected.

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) in the southern hemisphere, although parts of it have rotated out of view over the west limb. In the northern hemisphere, there is one smaller, positive polarity coronal hole, that crossed the central meridian on 24 April. On the eastern part of the Sun, there is a transequatorial elongated negative polarity coronal hole.

Solar wind

The Earth is within slow solar wind, with speeds close to 400 km/s and interplanetary magnetic field around 6 nT. Similar conditions are expected in the next 24 hours, with small chances of seeing the arrival of a high speed stream from the positive polarity coronal hole in the southern hemisphere (SIDC Coronal Hole 104).

Geomagnetism

Geomagnetic conditions have been quiet to unsettled globally and locally (Kp and K_Bel up to 3). The possible arrival of a high speed solar wind stream may increase conditions to active levels. Otherwise, mostly quiet conditions can be expected.

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 19has been above the threshold over the past 24 hours. The greater than 2 MeV electron flux may decrease over the next 24 hours.The 24-hour electron fluence is presently between normal and moderate levels, it may decrease over the next 24 hours.

Today's estimated international sunspot number (ISN): 114, based on 26 stations.

Solar indices for 27 Apr 2025

Wolf number Catania	///
10cm solar flux	156
AK Chambon La Forêt	012
AK Wingst	010
Estimated Ap	008
Estimated international sunspot number	124 - Based on 25 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