Viewing archive of Thursday, 15 May 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 May 15 1236 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Quiet

	10cm flux	Ap
15 May 2025	123	016
16 May 2025	124	020
17 May 2025	125	021

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours, with one M-class flare and a few C-class flares. The strongest flare was a M4.7 flare (SIDC Flare 4388) peaking at 18:11 UTC on May 14 and was associated with SIDC Sunspot Group 496 (NOAA Active Region 4087, magnetic type beta-delta). There are currently three numbered active regions on the solar disk. The most complex one is SIDC Sunspot Group 496 (NOAA Active Region 4087). SIDC Sunspot Group 494 (NOAA Active Region 4086) has rotated behind the west limb. SIDC Sunspot Group 450 (NOAA 4085) has decayed into plage. The solar flaring activity is expected to be low to moderate over the next 24 hours, with C-class flares expected, a chance for M-class flares and a small chance for X-class flares.

Coronal mass ejections

A faint Coronal Mass Ejection (CME), SIDC CME 498, directed to the northeast, was observed in LASCO/C2 and C3 coronagraph imagery starting from around 18:30 UTC on May 14. It is most likely associated with the M4.7 flare (SIDC Flare 4388) that peaked at 18:11 UTC on May 14. It is not expected to impact Earth. A CME (SIDC CME 499), directed to the southeast, was observed in LASCO/C2 and C3 coronagraph imagery starting from around 03:00 UTC on May 15. No clear source was identified on the visible disk, suggesting a backsided event that will not impact Earth.

Coronal holes

An elongated, mid-latitude, positive polarity coronal hole (SIDC Coronal Hole 104) is crossing the central meridian. An associated high-speed stream may arrive at Earth starting from May 18.

Solar wind

Over the past 24 hours, the solar wind parameters (ACE and DSCOVR) were slightly enhanced under the influence of the high-speed stream from the equatorial, negative polarity coronal hole (SIDC Coronal Hole 114). Speed values increased up to 480 km/s. The interplanetary magnetic field values were between 1 nT and 12 nT. The Bz component varied between -10 nT and 7 nT. The interplanetary magnetic field phi angle was mostly in the negative sector. Further enhanced solar wind conditions are expected over the next 24 hours, due to the expected arrival of the ICME associated with the Coronal Mass Ejection (CME) observed around 23:00 UTC on May 12.

Geomagnetism

Geomagnetic conditions globally were mostly at active levels (NOAA Kp 4- to 4). Geomagnetic conditions locally were mostly at unsettled levels (K BEL 3), with an interval of active levels (K BEL 4) between 18:00 UTC and 20:00 UTC on May 14. Minor storm conditions (NOAA Kp 5, K BEL 5), with possible isolated moderate storm conditions (NOAA Kp 6, K BEL 6), are expected over the next 24 hours due to the expected arrival of the ICME associated with the Coronal Mass Ejection (CME) observed around 23:00 UTC on May 12.

Proton flux levels

The greater than 10 MeV proton flux was below the 10 pfu threshold level 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 and GOES 19 was below the 1000 pfu threshold in the last 24 hours and is expected to remain so 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): 043, based on 20 stations.

Solar indices for 14 May 2025

Wolf number Catania	075
10cm solar flux	122
AK Chambon La Forêt	024
AK Wingst	018
Estimated Ap	018
Estimated international sunspot number	050 - Based on 31 stations

Noticeable events summary

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

All times in UTC

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