Viewing archive of Wednesday, 10 September 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Sep 10 1254 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
10 Sep 2025	120	019
11 Sep 2025	119	017
12 Sep 2025	119	013

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 C1.6 flare (SIDC Flare 5465) peaking on September 09 at 13:55 UTC, which was produced by SIDC Sunspot Group 628 (NOAA Active Region 4210). During the flare, the source region (AR 4210) of the flare had beta configuration of its photospheric magnetic field. A total of 8 numbered sunspot groups were identified on the disk over the past 24 hours. SIDC Sunspot Groups 631 and 634 (NOAA Active Region 4213 and 4214) are the complex regions with its beta-gamma 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

No Earth-directed coronal mass ejections (CME) were detected in the available coronagraph observations during last 24 hours.

Coronal holes

Recurrent negative polarity coronal hole (SIDC Coronal Hole 116), which spans from 10 S to 30 N, has started to cross the central meridian on Sep 10. The high speed streams originating from this coronal hole are expected to impact the Earth from Sep 13.

Solar wind

Earth continues to be under the influence of the fast solar wind. The solar wind speed ranged from 415 km/s to 590 km/s. The North- South component (Bz) ranged between -7 and 7 nT. The interplanetary magnetic field ranged from 1 nT to 8 nT. In the next 24 hours, we expect a gradual transition from fast to slow solar wind, unless there is a further arrival of high speed streams from the SIDC Coronal Hole 123 (positive polarity, elongated coronal hole in the southern hemisphere) which crossed the central meridian during Sep 02-09.

Geomagnetism

Geomagnetic conditions were globally at quiet to moderate storm conditions (NOAA Kp 1 to 6-). It was locally over Belgium at quiet to active conditions (K BEL 1 to 4). Global geomagnetic condition was at moderate storm conditions from 21:00 on Sep 09 to 00:00 UTC on Sep 10, possibly as the result of the ongoing influence of high speed streams (HSS) from the southern, positive polarity, recurrent coronal hole (SIDC Coronal Hole 123). Further moderate storm conditions are possible in the next 24 hours if there is any further arrival of HSSs from the same coronal hole, otherwise we expect quiet to active conditions (K 1 to 4).

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

The greater than 2 MeV electron flux, as measured by GOES-19, reached above the 1000 pfu threshold level from 14:15 UTC to 20:00 UTC on Sep 09. The greater than 2 MeV electron flux, as measured by GOES-18 reached above the 1000 pfu threshold level from 15:45 UTC on Sep 09 to 00:30 UTC on Sep 10. In the next 24 hours, the electron flux is expected to 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): 094, based on 18 stations.

Solar indices for 09 Sep 2025

Wolf number Catania	117
10cm solar flux	121
AK Chambon La Forêt	032
AK Wingst	017
Estimated Ap	017
Estimated international sunspot number	102 - Based on 21 stations

Noticeable events summary

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

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