Viewing archive of Tuesday, 12 August 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Aug 12 1231 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
12 Aug 2025	145	019
13 Aug 2025	145	021
14 Aug 2025	145	017

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours, with four M-class flares identified. A total of 10 numbered sunspot groups were observed on the solar disk. The most complex regions include SIDC Sunspot Group 590 (NOAA Active Region 4172), located at N09W18, with a Beta-Gamma magnetic configuration, and SIDC Sunspot Group 596 (NOAA Active Region 4178), located at N10W51, which has a Beta magnetic configuration and was growing. The most productive region was the SIDC Sunspot Group 588 (NOAA Active Region 4168) which as now turned over the West limb. The largest flare was an M1.8 flare (SIDC Flare 5122), peaking on August 12 at 01:23 UTC, produced by SIDC Sunspot Group 581 (NOAA Active Region 4165). Additionally, an M1.6 flare (SIDC Flare 5116) peaked on August 11 at 15:36 UTC, and an M1.5 flare (SIDC Flare 5114) peaked on August 11 at 14:35 UTC, both produced by SIDC Sunspot Group 588 (NOAA Active Region 4168). Another M1.5 flare (SIDC Flare 5121) peaked on August 12 at 00:59 UTC, also produced by SIDC Sunspot Group 581. Solar flaring activity is expected to remain moderate over the next 24 hours, with C-class flares expected and M-class flares likely.

Coronal mass ejections

Several coronal mass ejections (CMEs) were observed over the past 24 hours from the west limb. These CMEs are likely associated with activity near SIDC Sunspot Group 592 (NOAA Active Region 4173) and SIDC Sunspot Group 588 (NOAA Active Region 4168), both of which have rotated over the west limb. Due to their source location, these CMEs are not expected to impact Earth. No other Earth-directed CMEs were observed in the available coronagraph imagery over the past 24 hours.

Coronal holes

We have three coronal holes on the disc: One small coronal hole, SIDC Coronal Hole 125, positioned on the western side of the Sun. The elongated, southern, positive polarity SIDC Coronal Hole 123 continues to cross the central meridian since August 6. Additionally, SIDC Coronal Hole 116, a mid-latitude coronal hole with negative polarity, has returned and is now positioned on the eastern side of the Sun.

Solar wind

The solar wind conditions over the past 24 hours have been enhanced, influenced by high-speed streams associated with the SIDC Coronal Hole 123. The interplanetary magnetic field (Bt) varied between 5 nT and 8.5 nT, with the Bz component fluctuating between -6.6 nT and 7.5 nT. Solar wind speed increased from 500 km/s to 634 km/s. The interplanetary magnetic field (IMF) angle phi remained in the positive sector. Enhanced solar wind conditions are expected to persist, driven by the high-speed streams from SIDC Coronal Hole 123.

Geomagnetism

Geomagnetic conditions over the past 24 hours have ranged from quiet to Active, with K-Bel indices at 2 (quiet) and 3 (unsettled), and NOAA Kp indices at 3 (unsettled) and 4 (active). These conditions are in response to high-speed streams associated with SIDC Coronal Hole 123, along with Bz being negative for an extended period. Unsettled conditions are expected to continue, with a possibility of active periods.

Proton flux levels

The greater than 10 MeV proton flux remains below the 10 pfu threshold. It is expected to stay below the threshold level over the next 24 hours, pending no significant eruptive activity from sunspot regions.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 and GOES 19 showed values above the 1000 pfu threshold in response to the high-speed streams associated with the SIDC Coronal Hole 123. This electron flux is expected to fluctuate around the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence is currently at moderate levels and is expected to remain at these levels over the next 24 hours, with a possible increase over the next 48 hours.

Today's estimated international sunspot number (ISN): 170, based on 24 stations.

Solar indices for 11 Aug 2025

Wolf number Catania	///
10cm solar flux	146
AK Chambon La Forêt	026
AK Wingst	020
Estimated Ap	020
Estimated international sunspot number	176 - Based on 31 stations

Noticeable events summary

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

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