Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 May 25 1231 UTC

SIDC Forecast

Solar flares

C-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
25 May 2025	123	008
26 May 2025	124	007
27 May 2025	125	007

Solar Active Regions and flaring

Solar flaring activity over the last 24 hours has been high, with one X-class flare and three M-class flares. The strongest flare was an X1.1 flare (SIDC Flare 4453) peaking at 01:52 UTC on May 25, associated with SIDC Sunspot Group 506 (NOAA Active Region 4098, magnetic type beta-gamma-delta). There are currently nine numbered active regions on the solar disk. The most complex one is SIDC Sunspot Group 506 (NOAA Active Region 4098). SIDC Sunspot Group 508 (magnetic type beta) has rotated on disk from the east limb, in the southeast quadrant. The solar flaring activity is expected to be low to moderate over the next 24 hours, with C-class flares expected and a chance for M-class flares.

Coronal mass ejections

A narrow Coronal Mass Ejection (CME), SIDC CME 509, was observed in LASCO/C2 coronagraph imagery, starting from around 02:45 UTC on May 25, lifting off the west limb. It is most likely associated with the X1.1 flare (SIDC Flare 4453) that peaked at 01:52 UTC. It is not expected to impact Earth. A narrow CME (SIDC CME 510) was observed in LASCO/C2 coronagraph imagery, starting from around 18:20 UTC on May 24, lifting off the west limb. It is most likely associated with the C5.3 flare (SIDC Flare 4442) that peaked at 16:47 UTC on May 24. It is not expected to impact Earth. A slow CME (SIDC CME 511) was observed in LASCO/C2 coronagraph imagery around 17:25 UTC on May 24, lifting off the east limb. It is most likely a backsided event and it is not expected to impact Earth. No other Earth-directed CMEs were observed in the available coronagraph imagery.

Coronal holes

An equatorial, negative polarity coronal hole (returning SIDC Coronal Hole 99) is crossing the central meridian. An associated high- speed stream may arrive at Earth starting from the UTC evening of May 27. 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) were initially enhanced during the last 24 hours, possibly under the influence of the high-speed streams from the southern, positive polarity coronal hole (SIDC Coronal Hole 104) and possibly the northern, positive polarity coronal hole (SIDC Coronal Hole 115). The solar wind speed increased from 380 km/s to 480 km/s and has currently decreased to around 350 km/s. The interplanetary magnetic field ranged between 7 nT and 11 nT. The Bz component ranged between -6 nT and 7 nT. The interplanetary magnetic field angle phi was in the positive sector. Mostly slow solar wind conditions are expected over the next 24 hours.

Geomagnetism

Geomagnetic conditions globally and locally were at quiet levels (NOAA Kp 1+ to 2+, K BEL 1 to 2) over the past 24 hours. Mostly quiet to unsettled conditions (NOAA Kp 2 to 3), are expected over the next 24 hours.

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, pending no further eruptive activity from SIDC Sunspot Group 506 (NOAA Active Region 4098).

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 was over the 1000 pfu threshold between 16:10 UTC on May 24 and 01:45 UTC on May 25. The greater than 2 MeV electron flux measured by GOES 19 was over the 1000 pfu threshold between 16:10 UTC and 18:45 UTC on May 24. The greater than 2 MeV electron flux is expected to remain below the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence is presently at normal levels and is expected to remain so over the next 24 hours.

Today's estimated international sunspot number (ISN): 100, based on 14 stations.

Solar indices for 24 May 2025

Wolf number Catania	///
10cm solar flux	///
AK Chambon La Forêt	010
AK Wingst	///
Estimated Ap	006
Estimated international sunspot number	109 - Based on 13 stations

Noticeable events summary

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