Viewing archive of Friday, 21 March 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Mar 21 1242 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
21 Mar 2025	162	013
22 Mar 2025	158	019
23 Mar 2025	154	013

Solar Active Regions and flaring

A total of 14 numbered sunspot groups were identified on the disk over the past 24 hours. Solar flaring activity was low over the past 24 hours, with only C-class flares identified. The largest flare was a C4.4 flare (SIDC Flare 3884) peaking on March 20 at 17:10 UTC, which was produced by SIDC Sunspot Group 436 (NOAA Active Region 4025). All regions on disk have either an Alpha or Beta magnetic configuration. SIDC Sunspot Group 436 and 398 (NOAA 4025 and 4021) have started to rotate over the west limb. Solar flaring activity is expected to be moderate over the next 24 hours, with C-class flares expected and M-class flares likely.

Coronal mass ejections

No Earth-directed Coronal Mass Ejections (CMEs) have been detected in the available coronagraph images.

Solar wind

In the past 24 hours solar wind conditions at Earth were disturbed, due to an ICME glancing blow arrival, probably associated with a CME that left the Sun on March 17. The total interplanetary magnetic field started to increase, around 01:40 UTC on March 21, from 3 nT to a peak of 13 nT , with the Bz component reaching a minimum of -6 nT. The solar wind speed jumped, around 01:40 UTC on March 21, from 388 km/s to 440 km/s then gradually decreased to around 380 km/s. The phi-angle was mainly in the negative sector (directed towards the Sun) until 04:25 UTC on March 21 when it switched to the positive sector. The solar wind conditions are expected to remain enhanced due to the expected arrival of a high-speed stream on March 22.

Geomagnetism

The geomagnetic conditions over the past 24 hours globally and locally active (Kp 4 and K BEL 4). Active to minor storm conditions are expected for the next 24 hours.

Proton flux levels

Over the past 24 hours, the greater than 10 MeV GOES proton flux was at background levels and is expected to remain so over the next days.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux, as measured by GOES-18 satellites, exceeded the 1000 pfu threshold between 20:30 UTC and 23:00 UTC on March 20. The electron flux is expected to remain below the threshold in the coming 24 hours. 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): 159, based on 16 stations.

Solar indices for 20 Mar 2025

Wolf number Catania	132
10cm solar flux	170
AK Chambon La Forêt	015
AK Wingst	008
Estimated Ap	006
Estimated international sunspot number	166 - Based on 27 stations

Noticeable events summary

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

All times in UTC

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