Viewing archive of Monday, 27 December 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Dec 27 1231 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Quiet

	10cm flux	Ap
27 Dec 2021	124	019
28 Dec 2021	123	024
29 Dec 2021	121	012

Bulletin

Solar activity was relatively quiet, with several low C class flares (the strongest of which a C3.2 flare peaking at 20:12 UT), of which many related to activity on the Western limb (region 2908 which turned around the limb). NOAA region 2915 and 2917 decayed to plage, and also NOAA region 2912 has almost lost its remaining spot. 2919 remained a unipolar region, while both 2918 and 2916 have simplified and consolidated, loosing the mixed polarity features. A new bipolar region 2920 emerged to the South-West of 2912. There also seems to be a formation of two new regions to the West of 2918, but these have not (yet) been classified. Overall, C flaring is likely with only a small chance for an M flare.

The CME related to the filament eruption from the South-Western quadrant yesterday appears to be too far South and West to affect the Earth. No other Earth directed CMEs have been detected in coronagraph data.

The greater than 10 MeV proton flux was at nominal levels in the past 24 hours and is expected to remain so in the next 24 hours. The greater than 2MeV electron flux reaches above the 1000 pfu threshold during the diurnal maxima and does so again today. The 24h electron fluence was at moderate levels and is expected to be at normal to moderate levels over the next 24 hours.

Slow Solar wind conditions were observed, with this morning a small shock in which Solar wind speed jumped from 330km/s to 370 km/s. The magnetic field magnitude jumped from 4 to 7 nT and has been elevated above 10nT since then. Bz attained a southward peak of -10nT and is currently around -5nT. The magnetic field phi angle was variable. The shock could be an early mark ahead of the expected high speed stream from the extension of the Northern polar coronal hole. Solar wind speed is expected to rise further with the expected arrival of the high speed stream later in the day and tomorrow.

Geomagnetic conditions were quiet (NOAA Kp and local K Belgium 0-2), just reaching unsettled levels recently following the Solar wind perturbations. Geomagnetic conditions are expected to become active with possibly minor geomagnetic storming, depending on how the current solar wind perturbations unfold.

Today's estimated international sunspot number (ISN): 111, based on 09 stations.

Solar indices for 26 Dec 2021

Wolf number Catania	///
10cm solar flux	125
AK Chambon La Forêt	010
AK Wingst	003
Estimated Ap	003
Estimated international sunspot number	091 - Based on 13 stations

Noticeable events summary

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

All times in UTC

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