Daily bulletin on solar and geomagnetic activity from the SIDC

Vydáno: 2025 May 23 1231 UTC

SIDC Forecast

Sluneční erupce

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

Geomagnetism

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

Sluneční protony

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

	10cm flux	Ap
23 May 2025	122	011
24 May 2025	123	008
25 May 2025	123	011

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 C2.5 flare (SIDC Flare 4435) peaking at 22:41 UTC on May 22, associated with SIDC Sunspot Group 504 (NOAA Active Region 4095, magnetic type beta- gamma). There are currently ten numbered active regions on the solar disk. The most complex one are SIDC Sunspot Groups 504 and 505 (NOAA Active Regions 4095 and 4097), both of magnetic type beta-gamma. SIDC Sunspot Groups 496 and 504 (NOAA Active Regions 4087 and 4095) are currently rotating behind the west limb. SIDC Sunspot Group 506 (magnetic type beta) has emerged in the southwest quadrant, north of SIDC Sunspot Group 482 (NOAA Active Region 4090). SIDC Sunspot Group 507 (magnetic type beta) has emerged in the southeast quadrant. The solar flaring activity is expected to be moderate over the next 24 hours, with M-class flares expected and a small chance for X-class flares.

Vyhazování koronální hmoty

A Coronal Mass Ejection (CME), SIDC CME 504, was observed in LASCO/C2 coronagraph imagery around 15:45 UTC on May 22, propagating to the northeast. It is likely associated with eruptive activity near the east limb and it is not expected to impact Earth. A large prominence eruption was observed in SDO/AIA 304 data around 06:30 UTC on May 23, over the northeast limb. An associated CME (SIDC CME 505) was observed in LASCO/C2 coronagraph imagery around 07:00 UTC on May 23, propagating to the northeast. It is not expected to impact Earth. No other Earth-directed CMEs were observed in the available coronagraph imagery.

Koronální díra

The equatorial, positive polarity coronal hole (SIDC Coronal Hole 115) continues to cross the central meridian since May 22. The elongated, mid-latitude, positive polarity coronal hole (SIDC Coronal Hole 104) continues to cross the central meridian since May 15.

Solární bouře

The solar wind conditions (ACE and DSCOVR) were enhanced during the past 24 hours, most likely due to the continuous influence of a high- speed stream from the southern, positive polarity coronal hole (SIDC Coronal Hole 104). The solar wind speed ranged between 460 km/s and 540 km/s. The interplanetary magnetic field values ranged from 5 nT to 8 nT. The Bz component ranged between -5 nT and 6 nT. The interplanetary magnetic field angle phi was in the positive sector. Further enhancements in the solar wind conditions may be expected over the next 24 hours, due to the small chance of arrival of a glancing blow associated with the Coronal Mass Ejection (SIDC CME 500, observed around 00:24 UTC on May 19) and the continuous influence of the high-speed stream from the southern, positive polarity coronal hole (SIDC Coronal Hole 104).

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), with isolated unsettled intervals (K BEL 3). Unsettled to active conditions, with possible isolated minor storm intervals (NOAA Kp 3 to 5), are expected over the next 24 hours, due to the small chance of arrival of a glancing blow associated with the Coronal Mass Ejection (SIDC CME 500) that was observed around 00:24 UTC on May 19 and the continuous influence of the high-speed stream from the southern, positive polarity coronal hole (SIDC Coronal Hole 104).

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 504 (NOAA Active Region 4095, magnetic type beta-gamma).

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 was over the 1000 pfu threshold between 16:00 UTC on May 22 and 01:15 UTC on May 23. The greater than 2 MeV electron flux measured by GOES 19 was over the 1000 pfu threshold between 12:00 UTC and 20:00 UTC on May 22, and it is currently above the threshold. 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 is presently at normal levels but may increase to moderate levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 129, based on 21 stations.

Solar indices for 22 May 2025

Wolf number Catania	128
10cm solar flux	120
AK Chambon La Forêt	009
AK Wingst	///
Estimated Ap	007
Estimated international sunspot number	104 - Based on 20 stations

Noticeable events summary

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