Viewing archive of Saturday, 26 October 2024

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2024 Oct 26 1231 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
26 Oct 2024	218	028
27 Oct 2024	222	043
28 Oct 2024	222	043

Solar Active Regions and flaring

Solar flaring activity reached high levels, with several C-class flares and one X-class flare recorded over the past 24 hours. The largest flare was an X1.8 flare (SIDC Flare 2398) peaking at 07:19 UTC on October 26, associated with SIDC Sunspot Group 249 (NOAA Active Regions 3872; beta-gamma-delta). There are currently twelve numbered active regions on the visible disk. SIDC Sunspot Group 249 (NOAA Active Regions 3872) was the main driver of the flaring activity observed over the past 24 hours together with SIDC Sunspot Group 273 (NOAA Active Region 3869; beta-gamma) and SIDC Sunspot Group 257 (NOAA Active Region 3873; beta). SIDC Sunspot Group 294 (NOAA Active Region 3870) was growing over the past 24 hours, but remained quiet. Other regions on the disk have simple configurations of their photospheric magnetic fields (alpha and beta) and did not show any significant flaring activity. Solar flaring activity is expected to be at moderate levels over the next 24 hours, with M-class flares very likely and a small chance for X-class flares.

Coronal mass ejections

A fast halo coronal mass ejection (CME) was observed in SOHO/LASCO-C2 coronagraph data starting at around 06:48 UTC on October 26. The CME is directed primarily to the southeast from Earth's perspective and is associated with the X1.8 flare from SIDC Sunspot Group 249 (NOAA Active Region 3872), along with Type II and Type IV radio emissions detected at 06:29 UTC on October 26. The CME has an estimated speed around 1500 - 1600 km/s. Preliminary analysis suggests that while the bulk of the ejecta is expected to miss Earth, a glancing blow could potentially arrive on October 28. Further analysis to determine potential impact on Earth is ongoing. No other Earth-directed coronal mass ejections (CMEs) have been detected in the available coronagraph imagery over the past 24 hours.

Solar wind

Over the past 24 hours, the solar wind parameters reflected slow solar wind conditions. The solar wind speed ranged between 300 and 350 km/s. The interplanetary magnetic field (IMF) was below 7 nT. The IMF phi angle was predominantly in the negative sector (directed towards the Sun). The southward component of the interplanetary magnetic field fluctuated between -4 nT and 7 nT. Today, since about 11:30 UTC on October 26, the total interplanetary magnetic field rose to 14 nT. This might be associated with arrival of the compression region in front of the expected HSS from a negative polarity coronal hole or with an ICME, more information will be given as more data becomes available. The solar wind parameters are expected to be slightly elevated during the next days due to the arrival of a high-speed stream from a negative polarity coronal hole, that began crossing the central meridian on October 22, along with the possible arrival of an ICME.

Geomagnetism

Geomagnetic conditions over the past 24 hours were quiet globally NOAA Kp: 1 to 2) and quiet to unsettled locally over Belgium (K-BEL: 1 to 3). Unsettled conditions, with possible isolated active and minor storm periods, are expected over the next 24 hours due to the arrival of a high-speed stream and the possible arrival of an ICME.

Proton flux levels

The greater than 10 MeV proton flux continued to increase over the past 24 hours due to the fast halo coronal mass ejection (CME), that was observed in SOHO/LASCO-C2 coronagraph data starting at around 03:48 UTC on October 24, X1.8 flare, peaking at 07:19 UTC on October 26, the full halo CME, observed in STEREO-A starting at 06:53 UTC on October 26, but remained below radiation storm levels. The greater than 10 MeV proton flux is expected to continue to increase with a chance of exceeding the minor storm levels in the coming days.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux, as measured by the GOES-16 satellite, remained below the 1000 pfu alert threshold, and it is expected to remain below the threshold during the next 24 hours. The 24h electron fluence was at normal levels and is expected to remain so.

Today's estimated international sunspot number (ISN): 228, based on 12 stations.

Solar indices for 25 Oct 2024

Wolf number Catania	///
10cm solar flux	209
AK Chambon La Forêt	007
AK Wingst	002
Estimated Ap	002
Estimated international sunspot number	175 - Based on 21 stations

Noticeable events summary

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

All times in UTC

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