Viewing archive of Monday, 1 September 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Sep 01 1233 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Major (ISES: Severe) magstorm expected (A>=100 or K>=7)

Solar protons

Proton event expected (10 pfu at >10 MeV)

	10cm flux	Ap
01 Sep 2025	211	040
02 Sep 2025	214	026
03 Sep 2025	210	013

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours. The largest flare was a C6.8 flare (SIDC Flare 5401) peaking on August 31 at 18:26 UTC, which was produced by SIDC Sunspot Group 592 (NOAA Active Regions 4173, 4202). A total of 10 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 and has a Beta- Gamma magnetic configuration. 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.

Solar wind

Over the past 24 hours the solar wind conditions at Earth were mildly disturbed, due to a high-speed stream (HSS), associated with SIDC Coronal Hole 122. The solar wind speed ranged from 380 km/s to 480 km/s. The total interplanetary magnetic field ranged from 5 nT to 8 nT, with the Bz component reaching a minimum of -5 nT. The phi-angle was mainly in the negative sector (directed towards the Sun), with periods in the positive sector. The solar wind conditions are expected to become disturbed in the next 24, due to the expected arrival of an ICME that left the Sun on August 30.

Geomagnetism

The geomagnetic conditions over the past 24 hours were globally and locally quiet to unsettled (Kp 1–3 & K BEL 1–3). Major storm conditions are expected for the next 24 hours, due to the arrival of an ICME.

Proton flux levels

Over the past 24 hours, the greater than 10 MeV GOES proton flux became elevated and is expected to cross the 10 pfu threshold 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): 183, based on 14 stations.

Solar indices for 31 Aug 2025

Wolf number Catania	///
10cm solar flux	217
AK Chambon La Forêt	015
AK Wingst	010
Estimated Ap	009
Estimated international sunspot number	189 - Based on 28 stations

Noticeable events summary

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

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