Viewing archive of Tuesday, 9 September 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Sep 09 1239 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
09 Sep 2025	123	013
10 Sep 2025	121	013
11 Sep 2025	120	007

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 C1.5 flare (SIDC Flare 5464) peaking on September 09 at 03:23 UTC, which was produced by SIDC Sunspot Group 624 (NOAA Active Region 4207). During the flare, the source region (AR 4207) of the flare had beta configuration of its photospheric magnetic field. A total of 6 numbered sunspot groups were identified on the disk over the past 24 hours. SIDC Sunspot Groups 624, 628, 630, and 631 (NOAA Active Regions 4207, 4210, 4212, and 4213) are the complex regions with its beta magnetic configurations. Solar flaring activity is expected to be at low to moderate levels over the next 24 hours, with C-class flares expected and a small chance for M-class flares.

Coronal mass ejections

A narrow coronal mass ejection (CME) was observed in SOHO/LASCO-C2 images on NW limb at 03:48 UTC on Sep 09 (about 40 deg). It was associated with C1.5 flare (peak: 03:23 UTC, N28 W51) from the SIDC sunspot group 624 (NOAA AR 4207), and it is not expected to arrive at Earth. No other Earth-directed CMEs were detected in the available coronagraph observations during last 24 hour.

Coronal holes

Recurrent SIDC Coronal Hole 123 (positive polarity, elongated coronal hole in the southern hemisphere) has crossed the central meridian, and the high speed streams originating from this coronal hole are expected to impact the Earth until Sep 11.

Solar wind

Over the past 24 hours, the solar wind parameters remained under the influence of high speed streams (HSSs) from the SIDC Coronal Hole 123 (positive polarity, elongated coronal hole in the southern hemisphere) which crossed the central meridian during Sep 02-09. The solar wind speed ranged from 410 km/s to 640 km/s. The North-South component (Bz) ranged between -5 and 5 nT. The interplanetary magnetic field ranged between 0 nT to 9 nT. In the next 24 hours, enhanced solar wind conditions are expected to continue possibly with the further arrival of HSSs from the same coronal hole.

Geomagnetism

Geomagnetic conditions were at quiet to unsettled conditions (NOAA Kp 2 to 3), globally and locally during the past 24 hours. We expect quiet to active conditions (K 1 to 4) in the next 24 hours with the further arrival of high speed streams from the SIDC Coronal Hole 123 (positive polarity) which crossed the central meridian during Sep 02-09.

Proton flux levels

The greater than 10 MeV GOES proton flux was below the threshold level over the past 24 hours and it is expected to remain so for the next 24 hours.

Electron fluxes at geostationary orbit

Over the past 24 hours, the greater than 2 MeV electron flux, as measured by GOES-18 satellite, remained below the 1000 pfu threshold level almost all the time, except for brief instance around 19:15 UTC and 23:00 UTC on Sep 08 during which it exceeded the threshold level. It was in response to the high solar wind speed associated with the SIDC Coronal Hole 123 (positive polarity) which crossed the central meridian during Sep 02-09. The greater than 2 MeV electron flux, as measured by GOES-19 satellite, remained below the threshold level. In the next 24 hours, the electron flux may briefly exceed the threshold level. The 24h electron fluence is presently at normal level, and it is expected to remain so in the next 24 hours.

Today's estimated international sunspot number (ISN): 103, based on 12 stations.

Solar indices for 08 Sep 2025

Wolf number Catania	///
10cm solar flux	124
AK Chambon La Forêt	017
AK Wingst	014
Estimated Ap	015
Estimated international sunspot number	118 - Based on 20 stations

Noticeable events summary

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

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