Viewing archive of Friday, 5 September 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Sep 05 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Quiet

	10cm flux	Ap
05 Sep 2025	161	016
06 Sep 2025	151	023
07 Sep 2025	148	007

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours, with 2 M-class flares identified. The largest flare was a M1.4 flare (SIDC Flare 5430) peaking on September 05 at 01:16 UTC and the second largest flare was a M1.0 flare (SIDC Flare 5428) peaking on September 04 at 13:44 UTC, both were produced by SIDC Sunspot Group 624 (NOAA Active Region 4207). A total of 9 numbered sunspot groups were identified on the disk over the past 24 hours. SIDC Sunspot Group 624 (NOAA Active Region 4207) is the largest and most magnetically complex (Beta- Gamma) region on disk and produced most of the flaring activity in the last 24 hours. Solar flaring activity is expected to be low over the next 24 hours, with C-class flares very likely and a chance for M-class flares.

Coronal mass ejections

No Earth-directed Coronal Mass Ejections (CMEs) have been detected in the available coronagraph images.

Solar wind

Slow solar wind conditions were recorded over the past 24 hours. The solar wind speed ranged from 395 km/s to 537 km/s. The total interplanetary magnetic field ranged from 6 nT to 9 nT, with the Bz reaching a minimum of -6 nT. The phi-angle was mainly in the positive sector (directed away from the Sun), with periods in the negative sector. The solar wind conditions are expected to become disturbed in the next 24 hours, due to the expected arrival of high-speed streams associated with SIDC Coronal Hole 123 and SIDC Coronal Hole 128.

Geomagnetism

The geomagnetic conditions over the past 24 hours were globally and locally quiet to unsettled (Kp 1-3 & K BEL 1-3). Active to minor storm condition are expected for the next 24 hours.

Proton flux levels

Over the past 24 hours, the greater than 10 MeV GOES proton was at background levels and is expected to remain so over the next days.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux, as measured by the GOES-18 and GOES-19 satellites, were below the 1000 pfu threshold in the last 24 hours. The 2 MeV electron flux is expected to remain below the threshold during the next 24 hour. The 24-hour electron fluence was at normal levels and is expected to remain at normal levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 149, based on 23 stations.

Solar indices for 04 Sep 2025

Wolf number Catania	162
10cm solar flux	172
AK Chambon La Forêt	019
AK Wingst	012
Estimated Ap	012
Estimated international sunspot number	164 - Based on 23 stations

Noticeable events summary

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

All times in UTC

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