Viewing archive of Thursday, 30 December 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Dec 30 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
30 Dec 2021	108	012
31 Dec 2021	104	021
01 Jan 2022	101	015

Bulletin

A number of C level flares occurred during the period. The largest of C8.3 magnitude peaking at 8:10UT originating from NOAA region 2918 (Catania group 96). That group seems overall in decay and it is now moving towards the West limb, but remains a likely flaring source. NOAA region 2916 (Catania group 97) remains the other most prominent region on disc. It again was quiet during the period, despite some new flux emergence in the trailing part. The bipolar region 2921 (Catania group 94) will round the West limb today while the bipolar region 2920 (Catania group 93) has meanwhile decayed to plage. The two additional simple alpha regions (NOAA 2917 and 2919) remained unipolar. Overall, flaring at C class is to be expected with only a small remaining chance for a possible M flare.

No Earth directed CMEs have been observed 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 remained under the 1000 pfu threshold. The 24h electron fluence was at normal levels and is expected to be at normal levels over the next 24 hours. A rise in electron fluxes is expected to build up in the next days with the expected continuing elevated Solar wind speeds.

An equatorial positive polarity coronal hole transited the central meridian and is expected to influence Solar wind conditions from around midnight January 1-2 onwards. Solar wind data showed the expected renewed increase in Solar wind conditions connected to the equatorial positive polarity coronal hole that crossed central meridian on December 26. Solar wind speed started to increase slowly yesterday afternoon and just recently exceeded the 500 km/s mark. A peak of over 20nT was observed in the compression region after midnight. The Bz component was mostly positive though, with a brief southward peak reaching -10nT. The magnetic field phi angle indicated connection to a positive polarity sector. Solar wind speed is expected to increase further and remain enhanced for another 24 hours before starting a slow decline. This in turn is expected to be followed by a renewed increase starting around midnight 1-2 January related to the other equatorial positive polarity coronal hole that crossed the central meridian in past 24 hours.

Geomagnetic conditions reached to unsettled conditions only (NOAA Kp and local K Belgium reaching 3). Geomagnetic conditions may still occasionally reach active levels in response to the elevated Solar wind conditions.

Today's estimated international sunspot number (ISN): 067, based on 09 stations.

Solar indices for 29 Dec 2021

Wolf number Catania	///
10cm solar flux	111
AK Chambon La Forêt	011
AK Wingst	008
Estimated Ap	007
Estimated international sunspot number	080 - Based on 12 stations

Noticeable events summary

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

All times in UTC

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