Viewing archive of Thursday, 26 June 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Jun 26 1247 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
26 Jun 2025	116	025
27 Jun 2025	115	041
28 Jun 2025	114	018

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 C1.3 flare peaking on June 26 at 08:55 UTC, which was produced by SIDC Sunspot Group 526 (NOAA Active Region 4117). During the flare, the source region (AR 4117) of the flare had beta configuration of its photospheric magnetic field. A total of 5 numbered sunspot groups were identified on the disk over the past 24 hours. SIDC Sunspot Group 530 (NOAA Active Region 4120) is the complex region with its beta-gamma magnetic configurations. The solar flaring activity is expected to be at low to moderate levels over the next 24 hours with C-class flares expected, M-class flares probable, and a small chance of X-class flares.

Coronal mass ejections

A coronal mass ejection (CME) was observed in SOHO/LASCO-C2 images around 19:24 UTC on Jun 25. It was associated with a filament eruption on NW quadrant of the Sun, which was part of an extended filament in the northern hemisphere. The CME has a projected width of about 70 deg, projected speed of about 450 km/s, and it is not expected to arrive at the Earth. No other Earth-directed CMEs were detected in the available coronagraph observations during last 24 hour.

Coronal holes

SIDC Coronal Hole 116 (negative polarity) has crossed the central meridian and the high speed streams originating from this coronal hole are expected to impact the Earth until Jun 28.

Solar wind

Earth is presently inside a fast solar wind stream, due to the arrival of high speed streams (HSSs) from the large SIDC Coronal Hole 116 (negative polarity) which started to cross the central meridian on Jun 21. The solar wind speed ranged from 380 km/s to 850 km/s. The interplanetary magnetic field ranged between 6 nT and 17 nT, and the North-South component (Bz) ranged betweeen -12 nT and 14 nT. In the next 24 hours, enhanced solar wind conditions are expected to continue with the further arrival of HSSs from the same coronal hole.

Geomagnetism

Geomagnetic conditions were globally at unsettled to active conditions (NOAA Kp 3 to 4), and locally at quiet to active conditions (K_BEL 2 to 4) during the past 24 hours. The disturbed geomagnetic conditions was due to the arrival of high speed streams (HSSs) from the large SIDC Coronal Hole 116 (negative polarity) which started to cross the central meridian on Jun 21. In the next 24 hours, unsettled to moderate storm conditions (K 3 to 6) are possible with the continuous arrival of HSSs from the same coronal hole.

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, briefly crossed the 1000 pfu threshold level around 13:30 UTC and 18:00 UTC on Jun 25. The greater than 2 MeV electron flux, as measured by GOES-18 satellite, reached above the threshold level at 17:15 UTC and dropped below it at 21:30 UTC on Jun 25. In the next 24 hours, the electron flux is expected to remain below the threshold level, but increasing above the threshold level cannot be excluded. 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): 104, based on 16 stations.

Solar indices for 25 Jun 2025

Wolf number Catania	113
10cm solar flux	117
AK Chambon La Forêt	028
AK Wingst	016
Estimated Ap	016
Estimated international sunspot number	091 - Based on 27 stations

Noticeable events summary

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

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