Viewing archive of Friday, 25 July 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Jul 25 1243 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
25 Jul 2025	156	016
26 Jul 2025	158	019
27 Jul 2025	158	007

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with only C-class flares. The strongest flare was a C7.4 flare (SIDC Flare 4944) peaking at 01:01 UTC on July 25, which was associated with SIDC Sunspot Group 564 (NOAA Active Region 4149, magnetic type beta-gamma). There are currently eleven numbered active regions on the solar disk. SIDC Sunspot Groups 564, 572 (NOAA Active Regions 4149, 4155) are the most complex Groups with magnetic type beta-gamma. SIDC Sunspot Group 574 (magnetic type alpha) and SIDC Sunspot Group 575 (magnetic type beta) have emerged near the center of the disk. The solar flaring activity is expected to be moderate over the next 24 hours, with C-class flares expected and M-class flares likely.

Coronal mass ejections

The faint partial halo Coronal Mass Ejection (SIDC CME 530), reported yesterday and observed in LASCO/C2 and C3 coronagraph imagery around 08:00 UTC on July 23, is expected to arrive at Earth starting from 15:00 UTC on July 26. A prominence eruption was observed in AIA 304 data around 14:00 UTC on July 24, in the west limb. An associated wide CME (SIDC CME 531) was observed in LASCO/C2 coronagraph imagery starting from around 16:30 UTC on July 24, lifting off the west limb. It is not expected to impact Earth. No other Earth-directed CMEs were observed in the available coronagraph imagery.

Solar wind

Over the past 24 hours, the solar wind parameters (ACE and DSCOVR) are gradually returning to a slow solar wind regime, under the waning influence of the high-speed stream associated with the negative polarity coronal hole (SIDC Coronal Hole 116). Solar wind speed values have decreased from around 700 km/s at 12:00 UTC on July 24 to the current values of around 530 km/s. The interplanetary magnetic field values were between 4 nT and 6 nT. The Bz component varied between -6 nT and 6 nT. The interplanetary magnetic field angle was mostly in the negative sector. Slow solar wind conditions are expected over the next 24 hours. Enhanced solar wind conditions may be possible starting from the UTC noon on July 26, due to the expected arrival of the ICME associated with the partial halo Coronal Mass Ejection (SIDC CME 530) of July 23.

Geomagnetism

Geomagnetic conditions globally and locally were mostly at quiet to unsettled levels (NOAA Kp 2 to 3, K BEL 1 to 3). Mostly quiet to unsettled conditions are expected globally and locally over the next 24 hours. Active to minor storm conditions may be possible globally and locally starting from the UTC noon on July 26, due to the expected arrival of the ICME associated with the partial halo Coronal Mass Ejection (SIDC CME 530) of July 23.

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 mostly above the 1000 pfu threshold in the last 24 hours, with short intervals in which it fell below the 1000 pfu threshold. The greater than 2 MeV electron flux is expected to remain around the 1000 pfu threshold levels in the next 24 hours. The 24-hour electron fluence is presently at moderate levels and is expected to remain so over the next 24 hours.

Today's estimated international sunspot number (ISN): 157, based on 15 stations.

Solar indices for 24 Jul 2025

Wolf number Catania	131
10cm solar flux	///
AK Chambon La Forêt	020
AK Wingst	020
Estimated Ap	019
Estimated international sunspot number	121 - Based on 27 stations

Noticeable events summary

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

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