Viewing archive of Saturday, 26 April 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Apr 26 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
26 Apr 2025	164	013
27 Apr 2025	165	016
28 Apr 2025	167	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 14 numbered sunspot groups were identified on the disk over the past 24 hours. The largest flare was a C1.6 flare peaking at 10:07 UTC, which was produced by SIDC Sunspot Group 458 (NOAA Active Regions 4075). 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

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. And one more, smaller, positive polarity coronal hole in the northern hemisphere that crossed the central meridian on 24 April.

Solar wind

The solar wind speed has been gradually decreasing to around 450 km/s in the last 24 hours, with an interplanetary magnetic field of 5 nT, and Bz mostly positive. In the next 24 hours we may see the arrival of a high speed stream if the solar wind from the positive polarity coronal holes in the southern and/or in the northern hemisphere arrive to the Earth.

Geomagnetism

Geomagnetic conditions have been quiet globally and locally (Kp and K_Bel up to 2). 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 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): 168, based on 16 stations.

Solar indices for 25 Apr 2025

Wolf number Catania	///
10cm solar flux	164
AK Chambon La Forêt	008
AK Wingst	004
Estimated Ap	004
Estimated international sunspot number	193 - Based on 17 stations

Noticeable events summary

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

All times in UTC

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