Viewing archive of Tuesday, 2 September 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Sep 02 1232 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

Moderate (ISES: Major) magstorm expected (A>=50 or K=6)

Solar protons

Quiet

	10cm flux	Ap
02 Sep 2025	190	029
03 Sep 2025	185	031
04 Sep 2025	181	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 C3.9 flare (SIDC Flare 5405) peaking on September 01 at 19:22 UTC, which was produced by SIDC Sunspot Group 614 (NOAA Active Region 4197). 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 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 moderate over the next 24 hours, with C-class flares expected and M-class flares likely.

Coronal mass ejections

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

Coronal holes

SIDC Coronal Hole 123 (equatorial coronal hole with a positive polarity) started crossing 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)

Solar wind

Over the past 24 hours, the solar wind conditions at Earth have become disturbed, due to the arrival of an ICME that left the Sun on August 30 at 20:12 UTC. The solar wind speed jumped from 377 km/s to 676 km/s, the total interplanetary magnetic field jumped from 5 nT to 26 nT and the solar wind density jumped from 3 ppcc to around 10 ppcc on September 01 at 20:20 UTC. Over the entire period, the Bz reached a minimum value of -23 nT. At the end of the period, the total interplanetary magnetic field remains elevated around 19 nT and the solar wind speed has a value around 550 km/s The solar wind conditions are expected to remain disturbed in the next 24, due to the ongoing ICME passage.

Geomagnetism

The geomagnetic conditions over the past 24 hours reached moderate storm conditions globally (Kp 6) and minor storm conditions locally (K BEL 5). For the next 24 hours, major storm conditions can be expected if Bz turns negative.

Proton flux levels

Over the past 24 hours, the greater than 10 MeV GOES proton flux decreased and is expected to return to background levels in the next 24 hours.

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): 175, based on 18 stations.

Solar indices for 01 Sep 2025

Wolf number Catania	198
10cm solar flux	202
AK Chambon La Forêt	036
AK Wingst	018
Estimated Ap	016
Estimated international sunspot number	186 - Based on 19 stations

Noticeable events summary

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

All times in UTC

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