Viewing archive of Tuesday, 17 June 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Jun 17 1246 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
17 Jun 2025	145	016
18 Jun 2025	143	021
19 Jun 2025	141	013

Solar Active Regions and flaring

Solar flaring activity was at moderate levels with one M-class flare registered over the past 24 hours. A total of six numbered sunspot groups were identified on the visible solar disk with SIDC Sunspot Group 523 (NOAA Active Region 4114) remaining the largest and most complex active region, classified as magnetic type beta-gamma-delta. Despite its complexity the region produced only C-class flaring. The largest flare was a M1.1 flare (SIDC Flare 4669) peaking on June 16 at 14:55 UTC produced by an active region behind the west limb. Some high C-class flaring was produced by an active region behind the east limb, which is expected to rotate on disc during the next 24 hours. The remaining active regions on the disc have been mostly simple and quiet. Solar flaring activity is expected to be moderate over the next 24 hours, with M-class flares very likely and a small chance for X-class flares.

Coronal mass ejections

The fast narrow coronal mass ejection (SIDC CME 519) first observed in the SOHO/LASCO C2 coronagraph data around 18:24 UTC on June 15 has been modelled to primarily miss the Earth with chances of a shock arrival on June 18. The wide westward CME observed around 02:12 UTC on June 16th (SIDC CME 520) is expected to miss the Earth. A chain of filament eruptions was observed in the north-east solar quadrant starting around UTC midnight on June 16. These eruptions are associated with a C4.5 flare from SIDC Sunspot Group 523 (NOAA Active Region 4114), peak time at 23:09 UTC on June 16. Related large coronal dimming was observed in the SDO/AIA images starting at 23:39 UTC on June 16. Associated faint north- eastward CME was observed in the SOHO/LASCO C2 coronagraph data starting at 00:48 UTC on June 17 (SIDC CME 521). The CME is estimated to travel off the Sun-Earth line and is not expected to arrive at Earth.

Coronal holes

A large positive polarity coronal hole (SIDC Coronal Hole 104) continues to reside on the central meridian. This is a mid-latitude southern coronal hole covering a large longitudinal range which first crossed the central meridian on June 11. A mild high speed stream emanating from it has already arrived to Earth and is expected to remain influencing the Earth over the week.

Solar wind

Over the past 24 hours the solar wind parameters (ACE and DSCOVR) were under the continuous mild influence from a high speed stream. The interplanetary magnetic field (B) was slightly enhanced with a maximum value of 9.6 nT and a minimum Bz of -6 nT. The solar wind speed reached a maximum of 548 km/s. The B field phi angle was predominantly in the positive sector (directed away from the Sun). The solar wind conditions are expected to continue to be under a mild influence of a high speed stream over the next days. Some influence from an interplanetary shock and a mild glancing blow arrival are possible throughout June 18.

Geomagnetism

The geomagnetic conditions over the past 24 hours were globally quiet to locally over Belgium quiet to unsettled. Predominantly quiet to unsettled geomagnetic conditions are expected for the next 24 hours with possible active conditions or isolated minor storms pending possible mild glancing blow and shock arrivals from two CMEs (SIDC CMEs 518 and 519) lifting off the solar surface on June 15.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux has been at nominal levels. The greater than 10 MeV GOES proton flux is expected to expected to remain at nominal levels, though some increase may occur pending any new fast eruptive solar activity.

Electron fluxes at geostationary orbit

The greater than 10 MeV GOES 16 electron fluxes were below the 1000 pfu threshold over the last 24 hours and the greater than 10 MeV GOES 18 electron flux has briefly reached the 1000 pfu threshold. The greater than 10 MeV electron flux is expected to exceed the 1000 pfu threshold in the next 24 hours. The 24-hour electron fluence was at nominal levels and is expected to remain so in the next 24 hours.

Today's estimated international sunspot number (ISN): 115, based on 23 stations.

Solar indices for 16 Jun 2025

Wolf number Catania	150
10cm solar flux	148
AK Chambon La Forêt	018
AK Wingst	014
Estimated Ap	013
Estimated international sunspot number	123 - Based on 25 stations

Noticeable events summary

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

All times in UTC

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