Viewing archive of Friday, 25 April 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Apr 25 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
25 Apr 2025	170	013
26 Apr 2025	172	016
27 Apr 2025	174	007

Solar Active Regions and flaring

A total of 15 numbered sunspot groups were identified on the disk over the past 24 hours. Only C-class flaring was observed in the last 24 hours. The largest one was a C3.0 flare (SIDC Flare 4197) peaking on April 25 at 04:05 UTC, which was produced by SIDC Sunspot Group 458 (NOAA Active Region 4045). Solar flaring activity is expected to be low over the next 24 hours, with C-class flares very likely and a chance for M-class flares.

Coronal mass ejections

A filament erupted over the NW limb, leading to a CME first seen at 06:36 UTC on 24 April by LASCO C2, with an angular width around 70 degrees. This CME is 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. There are two more, smaller, coronal holes in the northern hemisphere that crossed central meridian on 24 April.

Solar wind

The solar wind speed has been around 500 km/s in the last 24 hours, with an interplanetary magnetic field around 6 nT, and Bz mostly positive. In the next 24 hours 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 been quiet globally (Kp up to 2) and up to to unsettled levels 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 and 19 was below the threshold over the past 24 hours. The greater than 2 MeV electron flux may increase over the next 24 hours.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 10 stations.

Solar indices for 24 Apr 2025

Wolf number Catania	196
10cm solar flux	170
AK Chambon La Forêt	018
AK Wingst	014
Estimated Ap	014
Estimated international sunspot number	200 - Based on 15 stations

Noticeable events summary

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

All times in UTC

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