Viewing archive of Saturday, 24 May 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 May 24 1231 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
24 May 2025	123	008
25 May 2025	124	014
26 May 2025	125	007

Solar Active Regions and flaring

Solar flaring activity over the last 24 hours has been low, with only C-class flares. The strongest flare was a C5.9 flare (SIDC Flare 4441) peaking at 10:32 UTC on May 24, associated with SIDC Sunspot Group 506 (NOAA Active Region 4098, magnetic type beta). There are currently nine numbered active regions on the solar disk. The most complex ones are three active regions with magnetic type beta. SIDC Sunspot Groups 496 and 504 (NOAA Active Regions 4087 and 4095, magnetic type alpha and beta respectively) are currently rotating behind the west limb. SIDC Sunspot Group 507 has decayed into plage. The solar flaring activity is expected to be low over the next 24 hours, C-class flares expected and a small chance for M-class flares.

Coronal mass ejections

A halo Coronal Mass Ejection (CME), SIDC CME 506, was observed in LASCO/C2 and LASCO/C3 coronagraph imagery, starting from around 17:30 UTC on May 23. No clear source was identified on the visible disk, suggesting it was a backsided event which is not expected to impact Earth. A filament eruption was observed in SDO/AIA 304 data around 03:30 UTC on May 24, in the southwest quadrant. A narrow, associated CME (SIDC CME 507) was observed in LASCO/C2 coronagraph imagery, lifting off around 04:15 UTC on May 24. It is not expected to impact Earth. A faint partial halo CME (SIDC CME 508) was detected starting from around 08:30 UTC on May 24 in LASCO/C2 coronagraph imagery. The bulk of the ejecta is propagating to the northeast. No clear source was identified on the visible disk, suggesting it was a backsided event, which is not expected to impact Earth. No other Earth-directed CMEs were observed in the available coronagraph imagery.

Coronal holes

The elongated, mid-latitude, positive polarity coronal hole (SIDC Coronal Hole 104) continues to cross the central meridian since May 15.

Solar wind

The solar wind conditions (ACE and DSCOVR) are gradually returning to the slow wind regime, after a period of waning influence of the high-speed stream from the southern, positive polarity coronal hole (SIDC Coronal Hole 104). The solar wind speed decreased from 500 km/s to 380 km/s. The interplanetary magnetic field increased from 6 nT to 10 nT. The Bz component ranged between -5 nT and 7 nT. The interplanetary magnetic field angle phi was in the positive sector. Enhancements in the solar wind conditions may be expected over the next 24 hours, due to the possible arrival of a mild high-speed stream from the northern, positive polarity coronal hole (SIDC Coronal Hole 115).

Geomagnetism

Geomagnetic conditions globally were at quiet levels (NOAA Kp 1+ to 2+) over the past 24 hours. Geomagnetic conditions locally were mostly at quiet levels (K BEL 2), reaching unsettled levels (K BEL 3) between 12:00 UTC and 20:00 UTC on May 23. Unsettled to active conditions, with a chance for isolated minor storm intervals (NOAA Kp 3 to 5), are expected over the next 24 hours, due to the possible arrival of a mild high-speed stream from the northern, positive polarity coronal hole (SIDC Coronal Hole 115).

Proton flux levels

The greater than 10 MeV proton flux was below the 10 pfu threshold over the past 24 hours. It is expected to remain below the threshold level over the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 was over the 1000 pfu threshold between 15:05 UTC on May 23 and 01:00 UTC on May 24. The greater than 2 MeV electron flux measured by GOES 19 was over the 1000 pfu threshold until 18:00 UTC on May 23. The greater than 2 MeV electron flux is expected to be above the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence was at moderate levels but is expected to return to normal levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 111, based on 10 stations.

Solar indices for 23 May 2025

Wolf number Catania	///
10cm solar flux	122
AK Chambon La Forêt	014
AK Wingst	///
Estimated Ap	011
Estimated international sunspot number	128 - Based on 28 stations

Noticeable events summary

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

All times in UTC

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