Viewing archive of Tuesday, 23 December 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Dec 23 1252 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Quiet

	10cm flux	Ap
23 Dec 2025	135	024
24 Dec 2025	133	026
25 Dec 2025	131	027

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with only C-class flares identified. The largest flare was a C8.6 flare (SIDC Flare 6479) peaking on December 22 at 22:31 UTC, which was produced by SIDC Sunspot Group 735 (NOAA Active Region 4317). During the flare, the source region (SIDC Sunspot Group 735) of the flare had beta configuration of its photospheric magnetic field. A total of 7 numbered sunspot groups were identified on the disk over the past 24 hours. SIDC Sunspot Group 731 (NOAA Active Region 4316) has the most complex magnetic configuration (Beta-Gamma) and was growing over the past 24 hours. Solar flaring activity is expected to be low to moderate over the next 24 hours, with C-class flares expected and a chance for M-class flares.

Coronal mass ejections

A coronal mass ejection (CME) was observed on SOHO/LASCO-C2 images around 10:36 UTC on Dec 22, which is possibly asscoiated with a filament eruption around 09:00 UTC on the SE quadrant (S02 E37) of the Sun. It has a projected speed of about 400 km/s and a projected width of about 90 deg. A glancing blow, associated with this CME, may be expected at the Earth on Dec 25-26. No other Earth-directed CMEs were detected in the available coronagraph observations during last 24 hour.

Solar wind

Earth is still inside a fast solar wind stream, with the continuous arrival of high speed streams (HSSs) from the elongated, posiitve polarity, recurrent coronal hole (SIDC Coronal Hole 128) which started to cross the central meridian on Dec 20. The solar wind speed ranged from 620 km/s to 865 km/s. The interplanetary magnetic field ranged between 4 nT and 8 nT, and the North- South component (Bz) ranged betweeen -7 nT and 6 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 around 16:40 UTC on Dec 22, dropped below the threshold level arouond 03:00 UTC on Dec 23, and it is above threshold level since 09:20 UTC on Dec 23. The greater than 2 MeV electron flux, as measured by GOES-19 satellite, increased and exceed the threshold level from 14:40 UTC to 19:30 UTC on Dec 22. It was in response to the high speed streams (HSS) from the southern, positive polarity, recurrent coronal hole (SIDC Coronal Hole 128) which started to cross the central meridian from Dec 20. The electron flux is expected to remain above this alert level during most of the next period. The 24h electron fluence is presently at normal level, and it is expected to remain normal to moderate level in the coming 24 hours.

Today's estimated international sunspot number (ISN): 111, based on 03 stations.

Solar indices for 22 Dec 2025

Wolf number Catania	///
10cm solar flux	133
AK Chambon La Forêt	038
AK Wingst	029
Estimated Ap	029
Estimated international sunspot number	081 - Based on 09 stations

Noticeable events summary

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

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