Viewing archive of Tuesday, 24 December 2024

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2024 Dec 24 1318 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

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

Solar protons

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
24 Dec 2024	240	012
25 Dec 2024	240	021
26 Dec 2024	240	028

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours, with two M-class flares observed. A total of 11 numbered sunspot groups were identified on the solar disk during this period. SIDC Sunspot Group 341 (NOAA Active Region 3932), currently located at S17E27, is the most complex and active region on the disk. It has a Beta-Gamma- Delta magnetic configuration and remained stable over the past 24 hours. This region was responsible for both M-class flares recorded. The largest event was an M4.7 flare (SIDC Flare 3059), which peaked on December 24 at 00:19 UTC, followed by an M4.1 flare (SIDC Flare 3061) peaking at 08:41 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: Yesterday, a partial halo coronal mass ejection (CME) was observed in SOHO LASCO C2 imagery on December 23 at 11:36 UTC, directed toward the southwest. This CME was associated with a Type II radio emission, which began at 11:11 UTC with an estimated velocity of 731 km/s. The CME was also linked to solar dimming and the M8.9 flare (SIDC Flare 3058), which peaked at 11:12 UTC. The flare originated from SIDC Sunspot Group 341 (NOAA Active Region 3932), located in the southeastern quadrant (S35E20). Due to the location of the source region, this CME is believed to be Earth-directed. The projected speed in the plane of the sky was initially estimated at 563 km/s by the CACTus tool, but the actual speed is likely closer to 800-850 km/s. The CME is expected to impact Earth on December 26 at approximately 00:00 UTC, with a margin of error of +/- 12 hours. Today, another Type II radio emission was identified on December 24 at 08:41 UTC, with an estimated velocity of 568 km/s. Such emissions typically occur in association with a coronal mass ejection (CME) linked to a flare event. This radio emission may be associated with the M4.1 flare (SIDC Flare 3061), which peaked at 08:41 UTC on December 24. This flare was produced by SIDC Sunspot Group 341 (NOAA Active Region 3932) and may be accompanied by a CME. However, SOHO LASCO C2 imagery for this potential CME is not yet available. Further information about this event will be provided as data becomes available.

Coronal holes

The relatively small coronal hole, identified as SIDC Coronal Hole 84, located at mid-latitudes in the northern hemisphere with positive polarity, first reached the central meridian on December 23 and is now positioned on the eastern side of the Sun.

Solar wind

The solar wind at Earth ranged between 550 km/s and 650 km/s, 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 7 nT, with its southward component fluctuating between -6.5 nT and 6.0 nT. The solar wind speed is expected to gradually decline 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. These conditions are expected to remain mostly at unsettled levels in the next few hours. Then, there is a low probability of a glancing blow to Earth later today, on December 25, associated with the faint southward-directed coronal mass ejection. This may generate 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 a minor to major storm-level of the geomagnetic conditions, with the K-indices potentially reaching values between 5 and 7.

Proton flux levels

The greater-than-10 MeV GOES proton flux has remained elevated since its gradual increase on December 20. Although it remains below the proton event threshold and is showing a slow decay, the possibility of crossing the threshold within the next 24 hours cannot be ruled out, given the heightened activity and complexity observed in several 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): 182, based on 04 stations.

Solar indices for 23 Dec 2024

Wolf number Catania	///
10cm solar flux	238
AK Chambon La Forêt	021
AK Wingst	016
Estimated Ap	015
Estimated international sunspot number	213 - Based on 09 stations

Noticeable events summary

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

All times in UTC

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