Viewing archive of Thursday, 11 December 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Dec 11 1241 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
11 Dec 2025	161	020
12 Dec 2025	158	010
13 Dec 2025	155	027

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours, with two M-class flares. The strongest flare was an M4.4 flare (SIDC Flare 6377) peaking at 22:08 UTC on December 10, which was associated with SIDC Sunspot Group 709 (NOAA Active Region 4294, magnetic type beta-gamma). There are currently eight numbered active regions on the solar disk. The most complex one is SIDC Sunspot Group 709 (NOAA Active Region 4294). SIDC Sunspot Groups 721 and 722 (both of magnetic type beta) have emerged in the southwest and southeast quadrants, respectively. SIDC Sunspot Group 713 (NOAA Active Region 4298) has rotated across the west limb. The solar flaring activity is expected to be moderate over the next 24 hours, with M-class flares very likely and a small chance for X-class flares.

Coronal mass ejections

A wide Coronal Mass Ejection (SIDC CME 608), was observed in LASCO/C2 and C3 coronagraph imagery starting from around 22:30 UTC on December 10, lifting off the west limb. It is most likely associated with the M4.4 flare (SIDC Flare 6377) that peaked at 22:08 UTC on December 10. Preliminary analysis shows that it will not impact Earth. Further analysis is ongoing. No other Earth-directed CMEs were observed in the available coronagraph imagery.

Coronal holes

An elongated, northern, negative polarity coronal hole (returning SIDC Coronal Hole 142) continues to cross the central meridian since December 10. An associated high-speed stream may arrive at Earth starting from December 13.

Solar wind

The solar wind conditions (ACE) were enhanced over the last 24 hours, due to an ICME arrival. An increase in solar wind parameters was observed around 20:00 UTC on December 10. Solar wind speeds rose from approximately 400 km/s to 450 km/s, and the interplanetary magnetic field values increased from 2 nT to 18 nT. From 20:00 UTC on December 10 to 02:00 UTC on December 11, there was a prolonged interval of negative Bz, with values reaching a minimum of –16 nT. The interplanetary magnetic field (IMF) angle was mostly in the positive sector and shifted to the negative sector between 18:00 and 21:00 UTC on December 10. Enhanced solar wind conditions may be expected over the next 24 hours, due to ongoing ICME influence.

Geomagnetism

Global geomagnetic conditions escalated to moderate storm levels (NOAA Kp 6+ ) between 21:00 UTC on December 10 and 00:00 UTC on December 11, due to an ICME arrival. Locally, geomagnetic conditions reached moderate storm levels (K BEL 6) between 23:00 UTC on December 10 and 01:00 UTC on December 11. Further minor to moderate geomagnetic storm conditions remain possible in the next 24 hours.

Proton flux levels

The greater than 10 MeV proton flux was below the 10 pfu threshold level over the past 24 hours. It is expected to remain below the threshold level over the next 24 hours, pending no further eruptive activity from SIDC Sunspot Groups 709, 712 (NOAA Active Regions 4294, 4296).

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 and 19 was above the 1000 pfu threshold until around 22:00 UTC on December 10 and has since remained below the threshold. The greater than 2 MeV electron flux is expected to remain below the 1000 pfu threshold level over the next 24 hours. The 24-hour electron fluence is presently at normal levels and is expected to remain so over the next 24 hours.

Today's estimated international sunspot number (ISN): 117, based on 10 stations.

Solar indices for 10 Dec 2025

Wolf number Catania	133
10cm solar flux	168
AK Chambon La Forêt	///
AK Wingst	029
Estimated Ap	025
Estimated international sunspot number	128 - Based on 16 stations

Noticeable events summary

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

All times in UTC

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