SIDC Ursigram

:Issued: 2025 Dec 11 1241 UTC
:Product: documentation at http://www.sidc.be/products/meu
#--------------------------------------------------------------------#
# DAILY BULLETIN ON SOLAR AND GEOMAGNETIC ACTIVITY from the SIDC     #
# (RWC Belgium)                                                      #
#--------------------------------------------------------------------#
SIDC URSIGRAM 51211
SIDC SOLAR BULLETIN 11 Dec 2025, 1240UT
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)
PREDICTIONS FOR 11 Dec 2025  10CM FLUX: 161 / AP: 020
PREDICTIONS FOR 12 Dec 2025  10CM FLUX: 158 / AP: 010
PREDICTIONS FOR 13 Dec 2025  10CM FLUX: 155 / AP: 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 GEO: 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 ISN  : 117, BASED ON 10 STATIONS.

SOLAR INDICES FOR 10 Dec 2025
WOLF NUMBER CATANIA    : 133
10CM SOLAR FLUX        : 168
AK CHAMBON LA FORET    : ///
AK WINGST              : 029
ESTIMATED AP           : 025
ESTIMATED ISN          : 128, BASED ON 16 STATIONS.

NOTICEABLE EVENTS SUMMARY
DAY BEGIN MAX  END  LOC    XRAY OP  10CM Catania/NOAA RADIO_BURST_TYPES 
10  0946  0955 1002 ////// M1.0          21/4294      
10  1332  1343 1349 S22W62 M1.6 SF       21/4294      III/2II/2 
10  2158  2208 2214 S20W66 M4.4 2B       21/4294      V/3II/3 
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 #
#--------------------------------------------------------------------#