Viewing archive of Monday, 1 December 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Dec 01 1237 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

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

	10cm flux	Ap
01 Dec 2025	182	011
02 Dec 2025	182	009
03 Dec 2025	184	022

Solar Active Regions and flaring

Solar flaring activity has reached high levels with a short-lived X1.9 flare, start time 02:27 UTC, peak time 02:49 UTC, end time 03:06 UTC, recorded on Dec 01. The flare was produced by a returning region SIDC Sunspot Group 687/NOAA Active Region 4274 (magnetic type beta-gamma), which rotated over the north-east limb and is currently located around N22E77. A total of 8 sunspot groups were identified on the visible solar disk. The largest and most complex active region on the visible disk is SIDC Sunspot Group 709 (NOAA Active Region 4294), classified as magnetic type beta-gamma-delta. Despite its complexity the region has produced only high C-class flaring. Other regions producing high C-class flaring are SIDC Sunspot Group 710/NOAA Active Region 4295 (magnetic type alpha) and SIDC Sunspot Group 711/NOAA Active Region 4296 (magnetic type beta-gamma), as well as NOAA Active Region 4288, which has increased its magnetic complexity, currently classified as magnetic type beta-gamma-delta. The solar flaring activity is expected to be at moderate to high levels over the next 24 hours with likely M-class flares and chances of isolated X-class flaring.

Coronal mass ejections

A fast partial halo coronal mass ejection (CME) with estimated projected velocity of 850 km/s was detected in the LASCO/C2 coronagraph imagery starting at around 03 UTC. The CME was related to the X1.9 flaring activity produced by SIDC Sunspot Group 687/NOAA Active Region 4274 at the north-east limb. The CME is directed off the Sun-Earth line and no notable impact on Earth is expected. No other Earth-directed CMEs have been identified in the available coronagraph imagery over the past 24 hours.

Coronal holes

An equatorial negative polarity coronal hole has now crossed the central meridian. A high speed stream emanating from it is expected to arrive at Earth on Dec 03.

Solar wind

Over the past 24 hours the solar wind parameters (as measured by ACE at L1) have registered a waning influence of the previously active high speed stream. The solar wind speed started at around 630 km/s and smoothly decreased towards below 500 km/s at present. The magnitude of the interplanetary magnetic field, B, was weak with a maximum value of 6.2 nT and a minimum Bz component of - 5.1 nT. 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 decline towards background slow solar wind conditions in the next days. A new mild high speed stream arrival related to a negative polarity coronal hole currently residing on the central meridian is expected on Dec 03.

Geomagnetism

The geomagnetic conditions over the past 24 hours were predominantly quiet to unsettled with a single isolated active period as registered by NOAA Kp index between 00:00 and 03:00 UTC on Dec 01. Locally over Belgium only quiet to unsettled conditions were observed. The geomagnetic conditions over the next days are expected to be predominantly quiet to unsettled. Active levels and isolated minor storm conditions might be reached with the anticipated mild high speed stream arrival on Dec 03.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux has been at nominal levels. Some enhancements in the proton flux might be expected over the next days, possibly related to activity from SIDC Sunspot Group 687/NOAA Active Region 4274 and/or SIDC Sunspot Group 709 (NOAA Active Region 4294) and NOAA Active Region 4288.

Electron fluxes at geostationary orbit

The greater than 10 MeV electron flux (as measured by GOES 18 and GOES 19) has exceeded the 1000 pfu threshold over the last 24 hours and is expected to exceed the threshold again over the next 24 hours. The 24-hour electron fluence was at moderate levels and is expected to remain so over the next 24 hours.

Today's estimated international sunspot number (ISN): 151, based on 05 stations.

Solar indices for 30 Nov 2025

Wolf number Catania	///
10cm solar flux	180
AK Chambon La Forêt	024
AK Wingst	017
Estimated Ap	019
Estimated international sunspot number	102 - 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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