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Daily bulletin on solar and geomagnetic activity from the SIDC

Существующий: 2025 Dec 04 1302 UTC

SIDC Forecast

Солнечные вспышки

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

Geomagnetism

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

Солнечные протоны

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

	10cm flux	Ap
04 Dec 2025	212	027
05 Dec 2025	214	025
06 Dec 2025	214	015

Solar Active Regions and flaring

Solar flaring activity over the past 24 hours has reached moderate levels with background C-class flaring and isolated M-class flaring identified. The strongest activity was a M6.0 flare (SIDC Flare 6285) with peak time 02:50 UTC on Dec 04. The flare was associated with SIDC Sunspot Group 714 (NOAA Active Region 4300), which has exhibited some magnetic flux reconfiguration, retaining a beta-delta magnetic type classification. A total of 11 sunspot groups were identified on the visible solar disk. SIDC Sunspot Group 709 (NOAA Active Region 4294) and SIDC Sunspot Group 712 (NOAA Active Region 4296) remain the largest and most complex regions, both classified as magnetic type beta-gamma-delta. They have contributed to the observed flaring activity, including a C9.2 flare (SIDC 6284), peak time 00:16 UTC on Dec 04, associated to SIDC Sunspot Group 712. Other notable regions are SIDC Sunspot Group 687 (NOAA Active Region 4299), classified as magnetic type beta-delta, and a growing region SIDC Sunspot Group 715 (NOAA Active Region 4301), classified as magnetic type beta. Both have produced low levels of activity over the past 24 hours. The solar flaring activity is expected to be at moderate levels over the next 24 hours with background C-class flaring, very likely M-class flares and chances of isolated X-class flaring.

Выбросы корональной массы

A large filament eruption visible in the SDO/AIA 30.4 nm imagery in the western solar hemisphere has lifting off the solar surface on the UTC morning of Dec 03, triggering a follow up eruption a few hours later. A combined slow coronal mass ejection (CME) was detected in the LASCO/C2 coronagraph imagery starting at 09:21 UTC on Dec 03 with estimated projected velocity below 400 km/s and a coronal dimming was observed around 10:30 UTC. Initial modelling suggests that the CME will pass mostly off the Sun-Earth line. A minor glancing blow impact remains possible on Dec 06, but might be mixed within the waning influence of an ongoing high speed stream. SDO/AIA imagery suggests another possible eruption following the C4.4 flaring 05:38 UTC on Dec 04 associated to SIDC Sunspot Group 709 (NOAA Active Region 4294). A related coronal dimming is observed starting from 05:33 UTC that day. Further coronagraph imagery is awaited to evaluate the presence of any possible Earth-directed CME related to this activity. No other Earth-directed CMEs have been identified in the available coronagraph imagery over the past 24 hours.

Солнечный ветер

Over the past 24 hours the solar wind parameters (as measured by ACE at L1) were indicative of an expected arrival of a co-rotating interactive region and a consequent high-speed stream arrival from a re- current negative polarity coronal hole (SIDC 140), which crossed the central meridian on Nov 30. Related to this high-speed stream arrival the solar wind speed has increased to up to 771 km/s. The magnitude of the interplanetary magnetic field, B, has increased up 22.8 nT and the Bz component has reached a minimum of -15.4 nT. The B field phi angle has switched orientation from the positive to the negative sector (directed towards the Sun). The solar wind conditions are expected to remain elevated over the next days under the ongoing influence of the high-speed stream.

Geomagnetism

The global geomagnetic conditions over the past 24 hours were predominantly at minor storm levels with an isolated major storm interval registered between 18-21 UTC on Dec 03. Locally, over Belgium, the geomagnetic conditions were predominantly at active levels with 4 hours of moderate storm levels registered between 19 and 23 UTC on Dec 03. The geomagnetic conditions over the next 24 hours are expected to be predominantly at active to minor storm levels with chances of further isolated moderate storms depending on the orientation of the interplanetary magnetic field related to the ongoing high-speed stream arrival.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux has been at nominal levels and is expected to remain so over the next days with chances for some enhancements related to possible high flaring activity.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux (as measured by GOES 18 and GOES 19) has exceeded the 1000 pfu threshold over the last 24 hours. It is expected to remain under the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence was at moderate levels and is expected to decrease towards nominal levels.

Today's estimated international sunspot number (ISN): 184, based on 08 stations.

Solar indices for 03 Dec 2025

Wolf number Catania	///
10cm solar flux	209
AK Chambon La Forêt	063
AK Wingst	036
Estimated Ap	039
Estimated international sunspot number	175 - Based on 12 stations

Noticeable events summary

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

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