Viewing archive of Monday, 16 June 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Jun 16 1257 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
16 Jun 2025	171	018
17 Jun 2025	176	016
18 Jun 2025	177	015

Solar Active Regions and flaring

Solar flaring activity was at high levels with five M-class flares registered over the past 24 hours. A total of 7 numbered sunspot groups were identified on the visible solar disk with SIDC Sunspot Group 523 (NOAA Active Region 4114) being the largest and most complex active region. The region has beta-gamma-delta magnetic configuration and is responsible for most of the observed M-class flaring, including an M8.4 flare (SIDC Flare 4651) peaking on June 15 at 18:07 UTC. Other notable flaring activity was produced by SIDC Sunspot Group 513 (NOAA Active Region 4105) near the west limb and possibly neighbouring regions behind the west limb. The remaining active regions have been mostly simple and quiet. Solar flaring activity is expected to be at moderate to high levels over the next 24 hours, with very likely M-class flaring.

Coronal mass ejections

A fast narrow coronal mass ejection (CME) propagating north-ward was observed in SOHO/LASCO C2 coronagraph data around 18:24 UTC on June 16. The CME has a projected speed of above 1000 km/s and is associated with an M8.4 flare (SIDC Flare 4651) originating from SIDC Sunspot Group 523 (NOAA Active Region 4114). The event is accompanied by a large coronal wave, a wide white-light shock as well as several solar radio bursts. The bulk of the CME is estimated to be off the Sun-Earth line. Possible shock impact at Earth is undergoing further analysis. A wide westward CME was observed around 02:12 UTC on June 16th. The CME is associated with a C6.5-flare from near the west limb peaking at 01:48 UTC. The bulk of the CME is not expected to impact the Earth. Further analysis is ongoing to determine any possible glancing blow arrival.

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. The 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 enhanced with a maximum value of 10 nT and a minimum Bz of -8.5 nT. The solar wind speed reached a maximum of 540 km/s. The B field phi angle was in the positive sector (directed away from the Sun). The solar wind conditions are expected to continue to be elevated under the influence of a high speed stream over the next days. Possible influence of an interplanetary shock arrival is currently being investigated.

Geomagnetism

The geomagnetic conditions over the past 24 hours were quiet to active. Quiet to active geomagnetic conditions are expected for the next 48 hours with possible isolated minor storms.

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 remain below radiation storm levels, but may exhibit some increase related to the recent eruptive solar activity and possible shock wave acceleration.

Electron fluxes at geostationary orbit

The greater than 10 MeV GOES 16 and GOES 18 electron fluxes were below the 1000 pfu threshold over the last 24 hours and might reach 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): 125, based on 21 stations.

Solar indices for 15 Jun 2025

Wolf number Catania	///
10cm solar flux	161
AK Chambon La Forêt	019
AK Wingst	012
Estimated Ap	012
Estimated international sunspot number	149 - Based on 22 stations

Noticeable events summary

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

All times in UTC

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