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Daily bulletin on solar and geomagnetic activity from the SIDC

Emesso: 2021 Dec 06 1253 UTC

SIDC Forecast

Brillamenti solari

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

Quiet (A<20 and K<4)

Protoni solari

Quiet

	10cm flux	Ap
06 Dec 2021	082	006
07 Dec 2021	082	005
08 Dec 2021	082	007

Bulletin

Solar activity was at low levels with the X-ray flux mostly below C-class flare over the last 24 hours. Catania Sunspot 74 (NOAA Active Region 2898) has now fully turned over the west limb, nevertheless, a C1.6-class flare and several coronal mass ejections was observed from Earth prospective. Catania Sunspot 80 (NOAA Active Region 2902) and NOAA Active Region 2904 produced small C1.3-class flares. Solar activity is expected to be at low levels, with a slight chance for a C-class flare.

Multiple backside Coronal Mass Ejections (CMEs) with a relatively low speed (less than 600 km/s) were observed, and were associated with the activity beyond the west limb in Catania Sunspot 74 (NOAA Active Region 2898). A very faint CME was observed on December 5 around 14:00 UTC near the south- east limb. This CME is associated with the filament that was stretching across the central meridian in the southern hemisphere. Currently no strong Earth directed component of the CME is identified, however further analysis of the CME is currently in progress.

The greater than 10 MeV proton flux was at nominal levels in the past 24 hours and is expected to remain at nominal levels in the next 24 hours. The greater than 2 MeV electron flux exceeded the 1000 pfu alert threshold in the past 24 hours but is expected to remain just below or at this threshold in the next 24 hours. The greater than 2 MeV electron fluence was moderate levels in the past 24 hours and is expected to be at between nominal and moderate levels in the next 24 hours.

The solar wind speed (ACE+DSCOVR) remained elevated with values ranging between 430 km/s and 550 km/s. The total magnetic field was below 7 nT, and its southward component, Bz, fluctuated between -6 nT and +5.5 nT. The interplanetary magnetic field phi angle was predominantly in the positive sector (directed away from the Sun). The solar wind speed is expected to remain elevated with possible further enhancements due to the influence of the high-speed streams from the positive polarity Coronal Hole (CH) that began to traverse the central meridian on Dec 02. The solar wind is then expected to gradually return to a slow solar wind regime from Dec 07. A small equatorial CH (negative polarity) has crossed over the central meridian, the high-speed streams from this CH may enhance the solar wind parameters near Earth around December 10-11.

Geomagnetic conditions were quiet to unsettle over the past 24 hours (NOAA Kp and K-BEL recorded values of 1-3 and 1-2, respectively). Geomagnetic conditions are expected to be mostly quiet with isolated unsettled periods possible.

Today's estimated international sunspot number (ISN): 013, based on 11 stations.

Solar indices for 05 Dec 2021

Wolf number Catania	///
10cm solar flux	083
AK Chambon La Forêt	015
AK Wingst	010
Estimated Ap	009
Estimated international sunspot number	022 - Based on 21 stations

Noticeable events summary

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

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