Daily bulletin on solar and geomagnetic activity from the SIDC

Emès: 2025 Aug 14 1239 UTC

SIDC Forecast

Erupcions solars

C-class flares expected, (probability >=50%)

Geomagnetism

Active conditions expected (A>=20 or K=4)

Protons solars

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
14 Aug 2025	140	018
15 Aug 2025	140	019
16 Aug 2025	140	008

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with only C-class flares identified. A total of 11 numbered sunspot groups were observed on the solar disk. The most complex regions include SIDC Sunspot Group 596 (NOAA Active Region 4178), located at N09W76, with a Beta-Gamma magnetic configuration, and SIDC Sunspot Group 590 (NOAA Active Region 4172), located at N09W51, with a Beta magnetic configuration that was decreasing. Other regions showed limited activity: SIDC Sunspot Groups 594 (NOAA Active Region 4175) and 597 (NOAA Active Region 4179) were decreasing, SIDC Sunspot Group 600 was growing, while SIDC Sunspot Groups 522, 554, 558, 598, 602, and 601 remained stable. The largest flare was a C4.1 flare (SIDC Flare 5146) peaking on August 13 at 20:03 UTC, produced by SIDC Sunspot Group 590. Solar flaring activity is expected to remain low over the next 24 hours, with C-class flares very likely and a small chance for M-class flares.

Expulsions de masses coronals

No Earth-directed CMEs were observed over the past 24 hours. Only a very small number of minor CMEs were detected, all of which are not expected to impact Earth.

Forats coronals

SIDC Coronal Hole 123 (equatorial, positive polarity) first reached the central meridian on August 6 and is now positioned on the western side of the Sun, having finally stopped transiting the central meridian. The recurring SIDC Coronal Hole 104 (polar-south, positive polarity) reached the central meridian today. Additionally, SIDC Coronal Hole 116, a mid-latitude coronal hole with negative polarity, remains on the eastern side of the Sun.

Vent solar

Over the past 24 hours, solar wind conditions were influenced by high-speed streams associated with the positive-polarity SIDC Coronal Hole 123. This polar-south with mid-latitude extention first reached the central meridian on August 6 and completed its transit across the central meridian today, August 14. The total interplanetary magnetic field (Bt) remained around 5 nT and 6 nT. The southward component of the interplanetary magnetic field (Bz) was mostly negative, reaching up to -5.3 nT. Solar wind speed remained elevated, fluctuating between 450 km/s and 550 km/s. Due to the large longitudinal extent of SIDC Coronal Hole 123, elevated solar wind conditions are expected to persist for the next few days.

Geomagnetism

Geomagnetic activity was mostly unsettled over the past 24 hours, with NOAA Kp indices ranging from 2 (quiet) to 4 (active). The Belgian K-index similarly varied between 1 (quiet) and 4 (active), with short sporadic periods of active conditions in response to the elevated solar wind speed and the southward Bz component. Unsettled geomagnetic conditions are expected to continue over the next 24 hours with possible occasionally active conditions.

Proton flux levels

Proton flux remained below the 10 pfu threshold over the past 24 hours. Given the number of sunspot groups on the disk, and in particular the activity from SIDC Sunspot Groups 592 (NOAA Active Region 4173) and 588 (NOAA Active Region 4168), both of which have rotated over the west limb but remain magnetically connected to the Sun-Earth line, a slight enhancement of the proton flux cannot be fully excluded, though it is now considered unlikely.

Electron fluxes at geostationary orbit

The >2 MeV electron flux measured by GOES 18 and GOES 19 exceeded the 1000 pfu threshold in response to high-speed streams associated with SIDC Coronal Hole 123. Electron flux levels are expected to fluctuate around the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence remains at moderate levels and is expected to persist at these levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 172, based on 18 stations.

Solar indices for 13 Aug 2025

Wolf number Catania	///
10cm solar flux	140
AK Chambon La Forêt	025
AK Wingst	020
Estimated Ap	019
Estimated international sunspot number	184 - Based on 28 stations

Noticeable events summary

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