:Issued: 2025 Dec 06 1231 UTC :Product: documentation at http://www.sidc.be/products/meu #--------------------------------------------------------------------# # DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC # # (RWC Belgium) # #--------------------------------------------------------------------# SIDC URSIGRAM 51206 SIDC SOLAR BULLETIN 06 Dec 2025, 1230UT SIDC FORECAST SOLAR FLARES : M-class flares expected (probability >=50%) GEOMAGNETISM : Active conditions expected (A>=20 or K=4) SOLAR PROTONS : Warning condition (activity levels expected to increase, but no numeric forecast given) PREDICTIONS FOR 06 Dec 2025 10CM FLUX: 204 / AP: 011 PREDICTIONS FOR 07 Dec 2025 10CM FLUX: 202 / AP: 007 PREDICTIONS FOR 08 Dec 2025 10CM FLUX: 200 / AP: 007 Solar Active Regions and flaring: Solar flaring activity over the past 24 hours was low with only C-class flares identified. The strongest activity was a C6.4 flare (SIDC Flare 6304) with peak time 03:09 UTC on Dec 06 associated with SIDC Sunspot Group 709 (NOAA Active Regions 4294). A total of 8 numbered 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 regions, which produced most of the observed flaring activity. They are classified respectively as magnetic type beta-gamma-delta and magnetic type beta-delta. SIDC Sunspot Group 687 (NOAA Active Region 4299) has increased its underlying magnetic field complexity and is currently classified as magnetic type beta-gamma- delta. It has produced a C5.2 flare with peak time 22:48 UTC on Dec 06. The remaining regions have been mostly simple and quiet. The solar flaring activity is expected to be at moderate levels over the next 24 hours with background C-class flaring, likely M-class flares and small chances of isolated X-class flaring. Coronal mass ejections: No other Earth-directed coronal mass ejections (CMEs) have been identified in the available coronagraph imagery over the past 24 hours. Solar wind: Over the past 24 hours the solar wind parameters (as measured by ACE at L1) continued to register the influence of an ongoing high-speed stream. The solar wind speed remained rather fast with a recorded maximum value of 730 km/s. The magnitude of the interplanetary magnetic field, B, was mildly elevated registering values of up to 8 nT. The Bz component was relative weak with a minimum value of -6.3 nT. The B field phi angle was predominantly in the negative sector (directed towards the Sun) reflecting the polarity of the geo-effective coronal hole (SIDC 140). The solar wind conditions are expected to remain elevated over the next days under the ongoing influence of the high-speed stream with chances for additional minor enhancements on Dec 06 and Dec 07 related to any possible glancing blow influence from the modelled CMEs, which launched from the Sun on Dec 03 and Dec 04. Geomagnetism: The geomagnetic conditions over the past 24 hours were quiet to active. Quiet at active conditions are expected to prevail over the next 24 hours with remaining chances for isolated minor storm levels due to an ongoing influence of a high speed stream mixed with any possible minor glancing blow. 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 small chances for some enhancements related to possible high flaring activity. Electron fluxes at GEO: The greater than 2 MeV electron flux (as measured by GOES 18 and GOES 19) has briefly exceeded the 1000 pfu threshold over the last 24 hours. It is exceed to exceed the 1000 pfu threshold again in the next 24 hours. The 24-hour electron fluence was at nominal levels and is expected to increase towards moderate levels over the next 24 hours and remain at moderate levels over the next days. TODAY'S ESTIMATED ISN : 159, BASED ON 04 STATIONS. SOLAR INDICES FOR 05 Dec 2025 WOLF NUMBER CATANIA : 223 10CM SOLAR FLUX : 206 AK CHAMBON LA FORET : 023 AK WINGST : 016 ESTIMATED AP : 015 ESTIMATED ISN : 167, BASED ON 14 STATIONS. NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM Catania/NOAA RADIO_BURST_TYPES NONE END BT #--------------------------------------------------------------------# # Solar Influences Data analysis Center - RWC Belgium # # Royal Observatory of Belgium # # # # Website http://www.sidc.be. # # E-mail sidc-support@oma.be # # To unsubscribe http://www.sidc.be/registration/unsub.php # # # # Legal notices: # # - Intellectual Property Rights: # # http://www.astro.oma.be/common/internet/en/data-policy-en.pdf # # - Liability Disclaimer: # # http://www.astro.oma.be/common/internet/en/disclaimer-en.pdf # # - Use and processing of your personal information: # # http://www.astro.oma.be/common/internet/en/privacy-policy-en.pdf # #--------------------------------------------------------------------#