Daily bulletin on solar and geomagnetic activity from the SIDC

Emesso: 2025 Dec 22 1300 UTC

SIDC Forecast

Brillamenti solari

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

Geomagnetism

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

Protoni solari

Quiet

	10cm flux	Ap
22 Dec 2025	124	010
23 Dec 2025	123	014
24 Dec 2025	123	015

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours, with 1 M-class flare identified. The largest flare was a M1.3 flare (SIDC Flare 6467) peaking on December 21 at 18:27 UTC, which was produced by SIDC Sunspot Group 731 (NOAA Active Region 4316). A total of 6 numbered sunspot groups were identified on the disk over the past 24 hours. 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.

Espulsioni di massa coronale

A wide CME (~110 deg) on NE was first observed in SOHO/LASCO-C2 images around 05:00 UTC on Dec 22. This was possibly associated with the flaring activity from SIDC Sunspot Groups 735 and 736 (NOAA Active Region 4317). A glancing blow associated with this CME is possible at Earth but not very probable. No other Earth-directed CMEs were detected in the available coronagraph observations during last 24 hours.

Vento solare

Over the past 24 hours, the solar wind parameters remained under the influence of high speed streams (HSSs) from the southern, positive polarity coronal hole (SIDC Coronal Hole 128) that has been crossing the central meridian since December 20. The solar wind speed ranged from 520 km/s to 840 km/s. The North-South component (Bz) ranged between -12 and 7 nT. The interplanetary magnetic field ranged between 3 nT to 14 nT. In the next 24 hours, enhanced solar wind conditions are expected to continue with the further arrival of HSSs from the same coronal hole.

Geomagnetism

Geomagnetic conditions were globally at unsettled to minor storm conditions (NOAA Kp 3 to 5), and locally over Belgium at quiet to minor storm conditions (K BEL 2 to 5) during the past 24 hours, possibly as the result of the ongoing influence of high speed streams (HSS) from the southern, positive polarity, recurrent coronal hole (SIDC Coronal Hole 128). We expect unsettled to minor storm conditions (K 3 to 5)in the next 24 hours, possibly with the further arrival of HSSs from the same coronal hole.

Proton flux levels

The greater than 10 MeV GOES proton flux was below the threshold level over the past 24 hours and it is expected to remain so for the next 24 hours.

Electron fluxes at geostationary orbit

Over the past 24 hours, the greater than 2 MeV electron flux, as measured by GOES-18 satellite, exceeded above the 1000 pfu threshold level from 18:10 UTC on Dec 21 and finally dropped below the threshold around 00:10 UTC on Dec 22. The greater than 2 MeV electron flux, as measured by GOES-19 satellite, exceeded above the threshold level from 14:20 UTC to 16:10 UTC on Dec 21. In the next 24 hours, the electron flux may exceed the threshold level again. The 24h electron fluence is presently at normal level, and it is expected to remain so in the next 24 hours.

Today's estimated international sunspot number (ISN): 083, based on 08 stations.

Solar indices for 21 Dec 2025

Wolf number Catania	///
10cm solar flux	124
AK Chambon La Forêt	046
AK Wingst	030
Estimated Ap	032
Estimated international sunspot number	064 - Based on 12 stations

Noticeable events summary

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