Viewing archive of Wednesday, 25 December 2024

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2024 Dec 25 1306 UTC

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)

	10cm flux	Ap
25 Dec 2024	260	014
26 Dec 2024	260	024
27 Dec 2024	260	010

Solar Active Regions and flaring

Solar flaring activity remained moderate over the past 24 hours, with six M-class flares identified. Twelve numbered sunspot groups were observed on the solar disk. SIDC Sunspot Group 341 (NOAA Active Region 3932), currently at S18E13, continues to be the most complex and active region, maintaining a Beta-Gamma-Delta magnetic configuration. This region was responsible for several M-class flares, including the largest event: An M4.9 flare (SIDC Flare 3072) peaking on December 25 at 04:49 UTC. A new region, SIDC Sunspot Group 350 (NOAA Active Region 3938), has rotated over the east limb and is currently positioned at N20E66 with a Beta-Gamma magnetic configuration. This region exhibited intense flaring activity, producing the second-largest flare of the past 24 hours: An M2.8 flare (SIDC Flare 3073) peaking on December 25 at 04:30 UTC. A solar Type II radio emission was observed on December 25 at 04:47 UTC, which is most likely related to the flare. Additionally, SIDC Sunspot Group 344 (NOAA Active Region 3930), located at S23W89 with a Beta magnetic configuration, produced: An M1.0 flare (SIDC Flare 3069) peaking on December 24 at 20:28 UTC. Solar flaring activity is expected to remain moderate over the next 24 hours, with M-class flares very likely and a chance for X-class flares.

Coronal mass ejections

Over the past 24 hours, multiple faint and relatively slow coronal mass ejections (CMEs) were observed to the southeast in SOHO/LASCO-C2 imagery. These CMEs were associated with SIDC Sunspot Group 341 (NOAA Active Region 3932). Given their direction and slow speeds, these CMEs have a low probability of delivering a glancing blow to Earth. Other potential CMEs linked to these eruptions may exist, but further confirmation will require additional coronagraph analysis. The most recent CME was detected on December 25, 2024, at 08:12 UTC, directed to the southeast in SOHO/LASCO-C2 imagery. While partial SOHO/LASCO C2 imagery is available for this event, it is currently insufficient for a detailed analysis. Updates will be provided as more data becomes available.

Coronal holes

SIDC Coronal Hole 83, an equatorial coronal hole with negative polarity, first crossed the central meridian on December 19 and is now positioned on the eastern side of the Sun. Similarly, SIDC Coronal Hole 84, a mid-latitude coronal hole with positive polarity, first crossed the central meridian on December 23 and is now also positioned on the eastern side of the Sun.

Solar wind

The solar wind speed at Earth has started to decrease over the past 24 hours, dropping from approximately 640 km/s to 450 km/s. This high- speed stream was influenced by the arrival of a high-speed stream from SIDC Coronal Hole 83, a small equatorial coronal hole with negative polarity that crossed the central meridian on December 19. The total interplanetary magnetic field remained around 6.5 nT, with its southward component fluctuating between -5.3 nT and 4.7 nT. The solar wind speed is expected to continue gradually declining over the next 24 hours. There is a low probability of a glancing blow to Earth later today, December 25, associated with the faint southward-directed coronal mass ejection originating from SIDC Sunspot Group 341 (NOAA Active Region 3932) and observed on December 22 at 00:21 UTC by SOHO/LASCO C2. Additionally, the partial halo coronal mass ejection (CME) observed in SOHO LASCO C2 imagery on December 23 at 11:36 UTC is expected to impact solar wind conditions near Earth on December 26 at approximately 00:00 UTC, with a margin of error of +/-12 hours.

Geomagnetism

Geomagnetic conditions were unsettled both globally and locally, with Kp and K_BEL values ranging between 2 and 3, with a brief period of active conditions recorded by the NOAA-Kp index. These conditions are expected to remain mostly at unsettled levels over the next few hours. Later today, December 25, there is a low probability of a glancing blow to Earth from a faint southward-directed coronal mass ejection. This may result in some active geomagnetic conditions. Following this, the partial halo coronal mass ejection (CME) observed on December 23 at 11:36 UTC is expected to arrive near Earth on December 26 at approximately 00:00 UTC (±12 hours). Its impact is likely to cause minor to major storm-level geomagnetic conditions, with K-indices potentially reaching values between 5 and 7.

Proton flux levels

The greater-than-10 MeV GOES proton flux continues its gradual decrease following the enhancement that began on December 20. Although it is showing a slow decay, the possibility of crossing the threshold within the next 24 hours cannot be ruled out, given the heightened solar activity with multiple intense flares and coronal mass ejections produced by magnetically complex sunspot groups.

Electron fluxes at geostationary orbit

The greater-than-2 MeV electron flux measured by GOES 18 briefly exceeded the threshold level in the last 24 hours, between 15:00 UTC and 20:00 UTC, in response to the high-speed solar wind conditions. It is expected to remain below the threshold over the next 24 hours. The 24-hour electron fluence is currently at normal levels and is also expected to remain at normal levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 225, based on 05 stations.

Solar indices for 24 Dec 2024

Wolf number Catania	///
10cm solar flux	259
AK Chambon La Forêt	018
AK Wingst	012
Estimated Ap	011
Estimated international sunspot number	182 - Based on 04 stations

Noticeable events summary

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

All times in UTC

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