Viewing archive of Thursday, 28 May 2026

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2026 May 28 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
28 May 2026	142	014
29 May 2026	143	014
30 May 2026	144	013

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 C3.4 flare (SIDC Flare 7790) peaking at 12:16 UTC on May 27, associated with SIDC Sunspot Group 876 (NOAA Active Region 4451, magnetic type beta). There are currently twelve numbered active regions on the solar disk. The most complex ones have a beta magnetic configuration. SIDC Sunspot Group 883 (NOAA Active Region 4453, magnetic type beta) and SIDC Sunspot Group 872 (NOAA Active Region 4443, magnetic type alpha) are currently rotating across the west limb. SIDC Sunspot Group 880 (NOAA Active Region 4450) and SIDC Sunspot Group 881 have decayed into plage. The solar flaring activity is expected to be low over the next 24 hours, with C-class flares very likely and a chance for M-class flares.

Coronal mass ejections

No Earth-directed Coronal Mass Ejections (CMEs) were observed in the available coronagraph imagery during the last 24 hours.

Coronal holes

A small, equatorial, negative polarity coronal hole (SIDC Coronal Hole 165) is crossing the central meridian. A mild associated high- speed stream may arrive at Earth starting from the UTC evening on May 31.

Solar wind

Over the last 24 hours, the solar wind parameters (ACE and DSCOVR) reflected slow solar wind conditions. The solar wind speed varied between 380 km/s and 430 km/s. The interplanetary magnetic field was between 6 nT and 10 nT. The Bz component varied between -8 nT and 7 nT. The interplanetary magnetic field angle phi was predominantly in the negative sector. Mostly slow solar wind conditions are expected over the next 24 hours, with a chance for enhanced conditions in case of the late arrival of a mild, high-speed stream from the southern, negative polarity coronal hole (SIDC Coronal Hole 149).

Geomagnetism

Geomagnetic conditions globally were quiet to unsettled (NOAA Kp 2 to 3) during the last 24 hours. Geomagnetic conditions locally were quiet to unsettled (K Bel 1 to 3) during the last 24 hours. Mostly unsettled to active conditions (NOAA Kp 3 to 4), with a small chance for isolated minor storm intervals (NOAA Kp 5) are expected over the next 24 hours, in case of the late arrival of a mild, high-speed stream from the southern, negative polarity coronal hole (SIDC Coronal Hole 149).

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 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): 158, based on 24 stations.

Solar indices for 27 May 2026

Wolf number Catania	211
10cm solar flux	142
AK Chambon La Forêt	018
AK Wingst	014
Estimated Ap	015
Estimated international sunspot number	177 - Based on 30 stations

Noticeable events summary

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

All times in UTC

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