Viewing archive of Sunday, 10 August 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Aug 10 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
10 Aug 2025	141	017
11 Aug 2025	138	031
12 Aug 2025	135	013

Solar Active Regions and flaring

Solar flaring activity over the last 24 hours has been moderate, with three M-class flares and multiple C-class flares. The strongest flares were two M1.7 flares (SIDC Flares 5093 and 5101), peaking at 16:21 UTC on August 09 and at 03:12 UTC on August 10 respectively. Both flares were associated with SIDC Sunspot Group 588 (NOAA Active Region 4168, magnetic type beta-gamma). There are currently eleven numbered active regions on the solar disk. The most complex ones are SIDC Sunspot Groups 588, 590 and 596 (NOAA Active Regions 4168, 4172 and 4178, all magnetic type beta-gamma). SIDC Sunspot Group 597 (magnetic type alpha) has rotated on disc from the east limb, in the southeast quadrant. SIDC Sunspot Groups 581, 588, and 592 (NOAA Active Regions 4165, 4168, 4173) are currently rotating behind the west limb. SIDC Sunspot Groups 555 and 591 (NOAA Active Regions 4161 and 4170) have rotated behind the west limb. SIDC Sunspot Group 593 (NOAA Active Region 4174) has decayed into plage. The solar flaring activity is expected to be moderate over the next 24 hours, with M-class flares very likely.

Coronal mass ejections

A narrow Coronal Mass Ejection (SIDC CME 552) was observed in LASCO/C2 coronagraph imagery, starting from around 02:30 UTC on August 10, lifting off the west limb. It is most likely associated with eruptive activity near SIDC Sunspot Group 592(NOAA Active Region 4173). It is not expected to impact Earth. SIDC CME 551 was observed in LASCO/C2 coronagraph imagery, starting from 04:00 UTC on August 10, lifting off the east limb. It is most likely associated with eruptive activity near SIDC Sunspot Group 590 (NOAA Active Region 4172). It is not expected to impact Earth. No other Earth-directed CMEs were observed in the available coronagraph imagery over the last 24 hours.

Coronal holes

The elongated, southern, positive polarity coronal hole (SIDC Coronal Hole 123) continues to cross the central meridian since August 06

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 increased from 460 km/s to around 590 km/s. The interplanetary magnetic field decreased from around 15 nT to around 7 nT. The Bz component varied between -15 nT and 10 nT. The interplanetary magnetic field angle phi was in the positive sector. Enhanced solar wind conditions are expected over the next 24, under the combined effects of the high-speed stream from the elongated SIDC Coronal Hole 123 and another expected high-speed stream from the northern, positive polarity coronal hole (SIDC Coronal Hole 125).

Geomagnetism

Geomagnetic conditions globally reached moderate storm levels (Kp 6) between 15:00 UTC and 18:00 UTC on August 09, decreasing later to mostly active conditions (NOAA Kp 4- to 4+). Geomagnetic conditions locally reached minor storm levels (K Bel 5), decreasing later to mostly active conditions (K Bel 4). Active to minor storm conditions (NOAA Kp 4 to 5), with a change for isolated moderate storm periods (NOAA Kp 6) are expected over the next 24-48 hours, under the combined effects of the high-speed stream from the elongated SIDC Coronal Hole 123 and another expected high- speed stream from the northern, positive polarity coronal hole (SIDC Coronal Hole 125).

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 SIDC Sunspot Group 588 (NOAA Active Region 4168, magnetic type beta-gamma).

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 has been above the 1000 pfu threshold since 10:30 UTC on August 10. The greater than 2 MeV electron flux measured by GOES 19 has been above the 1000 pfu threshold since 11:40 UTC on August 10. The greater than 2 MeV electron flux is expected to be above the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence is presently at normal levels and is expected to remain so over the next 24 hours, with a possible increase over the next 48 hours.

Today's estimated international sunspot number (ISN): 177, based on 23 stations.

Solar indices for 09 Aug 2025

Wolf number Catania	///
10cm solar flux	140
AK Chambon La Forêt	035
AK Wingst	040
Estimated Ap	042
Estimated international sunspot number	164 - Based on 27 stations

Noticeable events summary

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

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