Viewing archive of Saturday, 30 May 2026

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2026 May 30 1234 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
30 May 2026	147	008
31 May 2026	148	013
01 Jun 2026	149	010

Solar Active Regions and flaring

Solar flaring activity has been low over the last 24 hours, with a few C-class flares. The strongest flare was a C4.7 flare (SIDC Flare 7806) peaking at 11:53 UTC on May 30, likely associated with SIDC Sunspot Group 873 (NOAA Active Region 4446, magnetic type beta). There are currently ten numbered active regions on the solar disk. The most complex one is SIDC Sunspot Group 879 (NOAA Active Region 4452, magnetic type beta-gamma). SIDC Sunspot Group 883 (NOAA Active Region 4453) and SIDC Sunspot Group 872 (NOAA Active Region 4443), have rotated behind the west limb. SIDC Sunspot Group 884 (NOAA Active Region 4456, magnetic type beta) has rotated on disk from the east limb, in the northeast quadrant. SIDC Sunspot Group 885 (magnetic type alpha) has emerged in the southeast quadrant. The solar flaring activity is expected to be low to moderate over the next 24 hours, with C-class flares very likely and a chance for M-class flares.

Coronal mass ejections

A partial halo Coronal Mass Ejection (SIDC CME 662) was observed in LASCO/C2, LASCO/C3 and STEREO-A coronagraph imagery, starting from 08:30 UTC on May 30, lifting off from the north limb with a projected speed of 550 km/s. 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 during the last 24 hours.

Solar wind

Over the last 24 hours, the solar wind parameters (ACE and DSCOVR) were slightly enhanced, possibly due to the arrival of a mild high- speed stream from the northern, negative polarity coronal hole (SIDC Coronal Hole 142). The solar wind speed increased from 420 km/s to 460 km/s. The interplanetary magnetic field increased from 6 nT to around 11 nT. The Bz component varied between -7 nT and 8 nT. The interplanetary magnetic field angle phi was predominantly in the negative sector. A return to slow solar wind conditions is expected over the next 24 hours.

Geomagnetism

Geomagnetic conditions globally were mostly unsettled (NOAA Kp 3- to 3) during the last 24 hours, reaching active levels (NOAA Kp 4) between 18:00 and 21:00 UTC on May 29. Geomagnetic conditions locally were mostly unsettled (K Bel 3), reaching active levels (K Bel 4) between 18:00 and 22:00 UTC on May 29. Mostly quiet conditions are expected over the next 24 hours.

Proton flux levels

The greater than 10 MeV proton flux was below the 10 pfu threshold during the last 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 slightly elevated but remained below the 1000 pfu threshold during the last 24 hours. The 24-hour electron fluence was at normal levels and it is expected to remain so over the next 24 hours.

Today's estimated international sunspot number (ISN): 131, based on 16 stations.

Solar indices for 29 May 2026

Wolf number Catania	///
10cm solar flux	148
AK Chambon La Forêt	031
AK Wingst	020
Estimated Ap	020
Estimated international sunspot number	145 - Based on 28 stations

Noticeable events summary

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

All times in UTC

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