Viewing archive of Sunday, 31 December 2023

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2023 Dec 31 1304 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Quiet

	10cm flux	Ap
31 Dec 2023	138	003
01 Jan 2024	140	030
02 Jan 2024	140	015

Solar Active Regions and flaring

The solar flaring activity remained at low levels with two impulsive high C-class flares produced from behind the north-east limb, possibly by returning region NOAA 3527. The strongest activity was a C9.7 flare with peak time 08:17 UTC on Dec 31st. This region is now rotating onto disc and, together with NOAA AR 3530 from behind the west limb, was responsible for most of the flaring activity over the past 24 hours. There are only three numbered active regions on the visible disc with NOAA AR 3534 (beta-gamma) being the most complex one with largest number of sunspots. It has undergone slight development, but nevertheless remained quiet and inactive. The solar flaring activity is expected to be at low levels over the coming days with probable C-class flares and some chances for isolated M-class flaring.

Coronal mass ejections

A partial halo coronal mass ejection (CME) was detected in the LASCO/C2 imagery after 07:00 UTC on Dec 30th. The CME is associated with a filament eruption and related long-duration C2.6 flaring from NOAA AR 3534 (beta). Coronal dimming is observed in the south-east quadrant after 08:00 UTC on Dec 30th. While the bulk of the eruption is off the Sun-Earth line, a minor glancing blow could impact Earth during the UTC night of Jan 2nd or UTC morning of Jan 3rd. The large filament in the north-west quadrant has erupted once again and appears related to a CME with coronal dimming observed after 09:00 UTC on Dec 31st. We are awaiting for coronagraph data to analyse the event. No other Earth-directed CMEs have been detected in the available coronagraph imagery over the past 24 hours.

Coronal holes

The long negative polarity coronal hole which resided on the central meridian in the past few days starts to slowly move westward. The high speed stream related to this coronal hole could arrive to Earth late on Dec 31st or early Jan 1st and is expected to last for several days.

Solar wind

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) registered nominal slow solar wind conditions. The solar wind velocity varied in the range of 273 to 480 km/s. The interplanetary magnetic field had a maximum value of 8 nT with a minimum Bz of -4 nT. The B field was solely in the negative sector (directed towards the Sun). The solar wind conditions in the next 24 hours are expected to registered disturbances due to expected high speed stream arrival later tonight or on Jan 1st. Disturbed conditions are expected to continue throughout Jan 2nd with a possible further enhancement on Jan 3rd subject to a minor glancing blow arrival from the partial halo CME on Dec 30th.

Geomagnetism

The geomagnetic conditions over the past 24 hours were quiet. Mostly quiet geomagnetic conditions are expected for Dec 31st. Quiet to active conditions with likely minor storm levels and possible isolated moderate storms are anticipated for Jan 1st. Quiet to active conditions with possible minor storms are expected for Jan 2nd and Jan 3rd.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux was at background levels and is expected to continue so over the next days.

Electron fluxes at geostationary orbit

The greater than 2 MeV GOES 16 electron flux was below the 1000 pfu threshold and is expected to remain so in the upcoming days.The 24h electron fluence was at nominal level and is expected to remain so in the next days.

Today's estimated international sunspot number (ISN): 050, based on 09 stations.

Solar indices for 30 Dec 2023

Wolf number Catania	///
10cm solar flux	140
AK Chambon La Forêt	006
AK Wingst	004
Estimated Ap	003
Estimated international sunspot number	068 - Based on 16 stations

Noticeable events summary

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

All times in UTC

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