Viewing archive of Monday, 11 August 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Aug 11 1235 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
11 Aug 2025	156	024
12 Aug 2025	156	022
13 Aug 2025	156	022

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours, with three M-class flares identified. The largest flare was an M2.2 flare (SIDC Flare 5104), peaking on August 10 at 15:07 UTC, produced by SIDC Sunspot Group 588 (NOAA Active Region 4168). Another M1.7 flare (SIDC Flare 5106) peaked on August 10 at 23:04 UTC, also from Sunspot Group 588. Additionally, an M1.3 flare (SIDC Flare 5111) peaked on August 11 at 03:52 UTC, originating from SIDC Sunspot Group 592 (NOAA Active Region 4173) located at the West limb. A total of 13 numbered sunspot groups were observed on the solar disk. The most complex regions include SIDC Sunspot Group 588 (NOAA Active Region 4168), located at N05W82, with a Beta-Gamma-Delta magnetic configuration, and SIDC Sunspot Group 590 (NOAA Active Region 4172), located at N09W04, exhibiting a Beta-Gamma magnetic configuration. SIDC Sunspot Group 596 (NOAA Active Region 4178), located at N10W37, shows a Beta magnetic configuration and was growing. 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

A large coronal mass ejection (CME) was observed on August 10, 2025, at 14:48 UTC from the west limb, with an estimated speed of 638 km/s in the plane of the sky and an angular width of about 100 degrees. This CME is likely associated with eruptive activity near SIDC Sunspot Group 592 (NOAA Active Region 4173), which has rotated over the west limb. Due to its location, this CME is 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: Two small ones positioned on the western side of the Sun, SIDC Coronal Hole 124 and SIDC Coronal Hole 125. The elongated, southern, positive polarity SIDC Coronal Hole 123 continues to cross the central meridian since August 6.

Solar wind

The solar wind parameters (ACE) over the last 24 hours were enhanced, under the influence of a high-speed stream from the southern, elongated, positive polarity coronal hole (SIDC Coronal Hole 123) and possibly a high-speed stream from the northern, positive polarity coronal hole (SIDC Coronal Hole 124). The solar wind speed ranged from 469 km/s to 600 km/s. The interplanetary magnetic field (Bt) varied between 2.5 nT and 7.5 nT, while the Bz component fluctuated between -6 nT and 6 nT. The interplanetary magnetic field angle phi remained in the positive sector. Enhanced solar wind conditions are expected to persist over the next 24 hours, under the combined effects of the high-speed streams from SIDC Coronal Hole 123 and the expected high-speed stream from SIDC Coronal Hole 125.

Geomagnetism

The geomagnetic conditions were mostly active, with NOAA Kp and K-bel index ranging from 1 to 4. These conditions are consistent with solar wind parameters under the influence of a high-speed stream. Geomagnetic conditions are expected to remain unsettle to active over the next 24 hours, with a slight possibility of brief increases to minor storm conditions, depending on solar wind dynamics.

Proton flux levels

The greater than 10 MeV proton flux was below the 10 pfu threshold over the past 24 hours. It is expected to remain below the threshold level over the next 24 hours, pending no further eruptive activity from sunspot groups.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 and GOES 19 has mostly remained above the 1000 pfu threshold. This electron flux is expected to stay above 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 for the next 24 hours, with a possible further increase over the next 48 hours.

Today's estimated international sunspot number (ISN): 179, based on 23 stations.

Solar indices for 10 Aug 2025

Wolf number Catania	///
10cm solar flux	153
AK Chambon La Forêt	034
AK Wingst	025
Estimated Ap	027
Estimated international sunspot number	178 - Based on 27 stations

Noticeable events summary

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

All times in UTC

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