Viewing archive of Wednesday, 3 September 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Sep 03 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
03 Sep 2025	178	014
04 Sep 2025	174	014
05 Sep 2025	170	017

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with only C-class flares identified. The largest flare was a C6.1 flare (SIDC Flare 5409) peaking on September 02 at 14:52 UTC, which was produced by SIDC Sunspot Group 617 (NOAA Active Region 4199). A total of 13 numbered sunspot groups were identified on the disk over the past 24 hours. SIDC Sunspot Group 614 (NOAA Active Region 4197) is the largest region on the disk, has a Beta-Gamma magnetic configuration 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

A filament eruption was seen in SDO/AIA 194 and 304 at 02:30 UTC on September 03, in the northwest quadrant of the Sun. Analysis on whether the associated CME will be geoeffective is ongoing.

Coronal holes

SIDC Coronal Hole 123 (equatorial coronal hole with a positive polarity) first reached the central meridian on September 02, its associated high-speed stream is expected to arrive at Earth on September 05. (Other crossing times: August 06) SIDC Coronal Hole 128 (equatorial coronal hole with a positive polarity) started crossing the central meridian on September 03, its associated high-speed stream is expected to arrive at Earth on September 06.

Solar wind

Over the past 24 hours, the solar wind conditions at Earth were disturbed under the influence of an interplanetary coronal mass ejection (ICME) that left the Sun on August 30 at 20:12 UTC. The solar wind speed ranged from 450 km/s to 602 km/s. The total interplanetary magnetic field ranged from 9 nT to 24 nT, with the Bz reaching a minimum of -15 nT. The solar wind conditions are expected to remain disturbed in the next 24, due to the waning influence of the ICME.

Geomagnetism

The geomagnetic conditions over the past 24 hours reached minor storm conditions globally (Kp 5) and active conditions locally (K BEL 4). Active conditions 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): 148, based on 12 stations.

Solar indices for 02 Sep 2025

Wolf number Catania	180
10cm solar flux	187
AK Chambon La Forêt	039
AK Wingst	028
Estimated Ap	033
Estimated international sunspot number	172 - Based on 20 stations

Noticeable events summary

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

All times in UTC

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