Viewing archive of Wednesday, 16 April 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Apr 16 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
16 Apr 2025	155	020
17 Apr 2025	156	019
18 Apr 2025	157	014

Solar Active Regions and flaring

Solar flaring activity over the last 24 hours has been moderate, with one M-class flare. The strongest flare was an M1.3 flare (SIDC Flare 4138) from beyond the west limb, peaking at 18:13 UTC on April 15. There are currently four numbered active regions on the solar disk. The most complex one is SIDC Sunspot Group 450 (NOAA Active Region 4060, magnetic type beta-gamma). A new, currently unnumbered active region (SIDC Sunspot Group 474, magnetic type beta) has rotated on disk from the east limb. A new, currently unnumbered active region (SIDC Sunspot Group 475, magnetic type beta) has emerged in the northeast quadrant, east of SIDC Sunspot Group 450 (NOAA Active Region 4060). The solar flaring activity is expected to be low over the next 24 hours, with C-class flares expected and a chance for M-class flares.

Coronal mass ejections

Two narrow Coronal Mass Ejections (CMEs) were observed in LASCO/C2 coronagraph imagery, lifting off the east limb. The first was observed around 15:00 UTC on April 15 and the second around 00:00 UTC on April 16. They are most likely associated with flaring activity near the east limb and they are not expected to impact Earth. A filament eruption was observed in SDO/AIA 304 data, near SIDC Sunspot Group 450 (NOAA Active Region 4060), but no associated CME was observed in the available coronagraph imagery. No other Earth-directed CMEs were observed in the available coronagraph imagery.

Solar wind

A shock was detected in the solar wind data (DSCOVR) at 16:35 UTC on April 15. The interplanetary magnetic field jumped from 6 nT to 17 nT and briefly reached values up to 23 nT. The Bz component jumped from -4 nT to -11 nT. The solar wind speed jumped from 400 km/s to around 480 km/s and then increased up to 620 km/s. The solar wind density at the shock jumped from 5.6 ppcc to around 24.4 ppcc. The shock is most likely related to the expected interplanetary Coronal Mass Ejection (ICME) arrivals, associated with the CMEs that lifted off around 23:00 UTC on April 12 and the partial halo CME that lifted off around 08:30 UTC on April 13. Further enhancements in the solar wind parameters may be expected over the next 24 hours, also in the case of an early arrival of the high-speed stream from SIDC Coronal Hole 105.

Geomagnetism

Geomagnetic conditions globally reached moderate storm levels (NOAA Kp 6 to 6+), between 18:00 UTC on April 15 and 00:00 UTC on April 16. Geomagnetic conditions locally reached minor storm levels (K BEL 5) at 17:00 UTC on April 16 and briefly escalated to moderate storm levels (K BEL 6) between 00:00 UTC and 01:00 UTC on April 16. Geomagnetic conditions globally and locally are currently at unsettled levels (NOAA Kp 3, K BEL 3). Mostly unsettled to active conditions (NOAA Kp 3 to 4, K BEL 3 to 4), with a chance for isolated minor storm periods (NOAA Kp 5, K BEL 5), are expected globally and locally over the next 24 hours, also in the case of an early arrival of the high-speed stream from SIDC Coronal Hole 105.

Proton flux levels

The greater than 10 MeV proton flux was below the 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 was above the threshold level between 13:30 UTC and 21:40 UTC on April 15. The greater than 2 MeV electron flux measured by GOES 19 was above the threshold level between 11:50 UTC and 17:20 UTC on April 15. The greater than 2 MeV electron flux is expected to remain below the 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): 087, based on 05 stations.

Solar indices for 15 Apr 2025

Wolf number Catania	///
10cm solar flux	153
AK Chambon La Forêt	051
AK Wingst	030
Estimated Ap	031
Estimated international sunspot number	070 - Based on 15 stations

Noticeable events summary

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

All times in UTC

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