Viewing archive of Sunday, 12 October 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Oct 12 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
12 Oct 2025	131	022
13 Oct 2025	135	024
14 Oct 2025	140	019

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with five C-class flares identified. SIDC flare 5714 was the brightest of all, a C2 that peaked on 11 Oct at 19:15 UTC. It is associated with SIDC Sunspot Group 666 (NOAA Active Region [AR] 4247, Beta magnetic configuration). Three of the flares were produced by SIDC Sunspot Group 639 (NOAA AR 4246, Beta magnetic configuration) and the last flare from SIDC Sunspot Group 621 (NOAA AR 4248 and 4250, Beta magnetic configuration). More C-class flaring activity is expected in the next 24 hours, from any of SIDC Sunspot Groups 639, 666, and 621. There is also a small chance for an M-class flare from SIDC Sunspot Group 621.

Coronal mass ejections

No Earth-directed Coronal Mass Ejections (CME) were observed in the last 24 hours. A CME seen in LASCO-C2 images as launched on 11 Oct at 18:48 UTC is a back-sided event and not expected to reach Earth.

Solar wind

The Solar Wind (SW) conditions are affected by a High Speed Stream (HSS) arrival on 11 Oct at around 21:30 UTC. It is associated with the SIDC Coronal Hole 116 crossing of the solar central meridian on 8 Oct. However, by that time the effects of the glancing blow associated with SIDC CME 578 had already subsided hence the two events did not coincide. As a result of the HSS arrival, the SW speed reached 800 km/s on 12 Oct at around 05:30 UTC and remains above 700 km/s since. The interplanetary magnetic field (B) peaked at 17 nT on 11 Oct 18:45 UTC, while still under the influence of the glancing blow, and have now dropped to around 5 nT. The B's North-South component (Bz) fluctuated between -10 and 10 nT while still affected by the glancing blow and now ranges between -5 and 5 nT. The presents of the HSS is expected to continue in the next 24 hours.

Geomagnetism

During the last 24 hours geomagnetic conditions were globally quiet to active (NOAA Kp 2+ to 4) and locally quiet to unsettled (K BEL 2 to 3). These were rather modest conditions considering the arrival of a High Speed Stream (HSS) late on 11 Oct. However, it can be explained by the relatively low interplanetary magnetic field and more importantly from the absence of a strong negative North-South interplanetary magnetic field component (Bz). In the next 24 hours the geomagnetic conditions are expected to be at active levels both globally and locally, however there is a change that minor storm levels might occur if there is a decrease in Bz.

Proton flux levels

The greater than 10 MeV proton flux, as measured by the GOES-19 satellite, was at background levels over the past 24 hours and is likely to remain so in the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux as measured by GOES 19 was above the 1000 pfu alert threshold on 11 Oct between 12:50 and 20:00 UTC, with a peak value at 2800 pfu, but has dropped below the alert level since. In the next 24 hours it is expected to remain below the alert threshold. The 24-hour electron fluence was at moderate levels during the past 24 hours. It is expected to drop to normal levels within the next 24 hours.

Today's estimated international sunspot number (ISN): 127, based on 09 stations.

Solar indices for 11 Oct 2025

Wolf number Catania	///
10cm solar flux	131
AK Chambon La Forêt	029
AK Wingst	018
Estimated Ap	018
Estimated international sunspot number	099 - 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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