Viewing archive of Monday, 4 May 2026

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2026 May 04 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
04 May 2026	141	009
05 May 2026	139	011
06 May 2026	137	007

Solar Active Regions and flaring

Solar flaring activity has reached moderate levels over the past 24 hours with 1 M-class flare identified. A total of 10 numbered sunspot groups were identified on the visible solar disk. All regions are relatively simply classified either as magnetic type alpha or beta. SIDC Sunspot Group 853 (NOAA Active Region 4428) currently located at S24W56 and SIDC Sunspot Group 859 (NOAA Active Region 4429) currently located at S04W11 (magnetic type beta) have exhibited some growth over the past 24 hours and have highest chances for flaring on the visible solar disc. The strongest detected activity was a M1.8 flare (SIDC Flare 7608) peaking on May 04 at 01:33 UTC, produced by SIDC Sunspot Group 851 (NOAA Active Region 4424). The region has now fully rotated behind the west limb. The solar flaring activity is expected to be at moderate levels over the next 24 hours with C-class flares expected and likely isolated M-class flaring particularly from SIDC Sunspot Group 851 (NOAA Active Region 4424).

Coronal mass ejections

No Earth-directed coronal mass ejections (CMEs) have been identified in the available coronagraph imagery over the past 24 hours.

Coronal holes

SIDC Coronal Hole 158 (recurrent equatorial coronal hole with a positive polarity) has crossed the central meridian on May 04. An associated high speed stream arrival might be expected at Earth on May 07 and May 08.

Solar wind

Over the past 24 hours the solar wind parameters (as measured by ACE at L1) have registered predominantly nominal slow solar wind conditions. The solar wind speed varied in the range of 330 km/s to 459 km/s. The interplanetary magnetic field (B) was slightly elevated with a maximum magnitude of 8.3 nT and a minimum north-south (Bz) component of - 6.3 nT. The B field phi angle remained predominantly in the negative sector (directed towards the Sun). The solar wind parameters are expected to reflect mostly nominal slow solar wind conditions over the next days until a possibly high-speed stream arrival late UTC on May 07 or May 08.

Geomagnetism

The geomagnetic conditions over the past 24 hours have been globally quiet with some isolated unsettled periods recorder over Belgium between 16h-20h UTC on May 03. Predominantly quiet to unsettled geomagnetic conditions are expected for the next days with possible active condition late on May 07 and May 08.

Proton flux levels

Over the past 24 hours the greater than 10 MeV GOES proton flux was at nominal levels and is expected to remain so over the 24 hours over the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux as measured by GOES 18 and GOES 19 was below the 1000 pfu threshold over the past 24 hours and is expected to remain so over the next days. The 24-hour electron fluence was at nominal levels and is expected to remain so over the 24 hours.

Today's estimated international sunspot number (ISN): 128, based on 12 stations.

Solar indices for 03 May 2026

Wolf number Catania	///
10cm solar flux	143
AK Chambon La Forêt	012
AK Wingst	012
Estimated Ap	011
Estimated international sunspot number	133 - Based on 13 stations

Noticeable events summary

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

All times in UTC

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