Viewing archive of Tuesday, 22 April 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Apr 22 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
22 Apr 2025	163	021
23 Apr 2025	165	019
24 Apr 2025	167	018

Solar Active Regions and flaring

A total of 8 numbered sunspot groups were identified on the disk over the past 24 hours. There were two M-class flares in the last 24 hours. The largest one was an M1.9 flare (SIDC Flare 4174) peaking on April 21 at 18:37 UTC, which was produced by SIDC Sunspot Group 473 (NOAA Active Region 4062). This AR, and one rotating into view from the east limb, may create significant flares. The second M-class flare was an M1.3 one from SIDC Sunspot Group 450 (NOAA Active Region 4060), rotiating out of view over the east limb. 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.

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 Earth is under the influence of a 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 reached 730 km/s (currently 630 km/s), the interplanetary magnetic field has reached 14 nT (currently around 5 nT) with Bz down to -9 nT (currently positive). The compression region between fast and slow solar wind has passed, we expect high solar wind speeds with low interplanetary magnetic field for the next 24 hours.

Geomagnetism

Geomagnetic conditions have reached minor storm levels both locally and planetary (K_Bel up to 5 between 14:00 and 17:00 UTC on 21 April, and Kp up to 5+ between 09:00 and 21:00 UTC on 21 April). Due to the ongoing effect of the high speed solar wind stream, active conditions can be expected (K up to 4) 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): 177, based on 22 stations.

Solar indices for 21 Apr 2025

Wolf number Catania	///
10cm solar flux	163
AK Chambon La Forêt	046
AK Wingst	037
Estimated Ap	039
Estimated international sunspot number	135 - Based on 19 stations

Noticeable events summary

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

All times in UTC

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