Viewing archive of Sunday, 26 September 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Sep 26 1247 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Quiet

	10cm flux	Ap
26 Sep 2021	088	005
27 Sep 2021	088	027
28 Sep 2021	089	011

Bulletin

Named regions present on the visible solar disk are Catania 45/NOAA 2871 and Catania 44/NOAA 2872. Regions Catania 43/NOAA 2873, Catania 48/NOAA 2875 and NOAA 2876 have turned into a plage. Catania 45/NOAA 2871 has been the source of a C1.7-class flare while plage Catania 43/NOAA 2873 was the source of a C1.0-class and also possibly a C1.6-class flare. Over the next 24 hours, C-class flares can be expected.

A CME associated with the filament eruption on Sep 24 17:12UT may have a glancing impact on Earth from late Sep 27.

The greater than 10 MeV proton flux was at background levels in the past 24 hours, and is expected to stay at nominal levels in the next 24 hours. The greater than 2 MeV electron flux remained below the 1000 pfu alert threshold. Over the next 24 hours, it is expected to slowly be enhanced but possibly remain below the threshold. The 24h electron fluence was at nominal levels over the past 24 hours. Over the next 24 hours it is expected to remain at those levels, possibly with values towards moderate levels.

Over the past 24 hours the solar wind speed has decreased to 405 km/s. The total magnetic field strength had values between 2 and 5 nT, while its Bz component varied between -3 and 4nT. Solar wind parameters are expected to gradually increase over the next 24 hours, as the effects of the high speed stream of the coronal hole crossing central meridian on Sep 24, together with possible impact of the CMEs from Sep 23 and Sep 24 are to be anticipated from late Sep 26-early Sep 27.

Geomagnetic conditions were at quiet levels (NOAA Kp and K Dourbes 0-2) over the past 24 hours. Quiet to unsettled conditions, with a chance of active periods can be expected over the next 24 hours.

Today's estimated international sunspot number (ISN): 045, based on 14 stations.

Solar indices for 25 Sep 2021

Wolf number Catania	///
10cm solar flux	088
AK Chambon La Forêt	///
AK Wingst	008
Estimated Ap	007
Estimated international sunspot number	043 - Based on 29 stations

Noticeable events summary

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

All times in UTC

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