Viewing archive of Tuesday, 31 August 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Aug 31 1258 UTC

SIDC Forecast

Solar flares

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Quiet

	10cm flux	Ap
31 Aug 2021	089	010
01 Sep 2021	088	010
02 Sep 2021	088	020

Bulletin

Catania sunspot group 32 (NOAA active region 2860) produced a number of C flares during the period of which the largest a C3.0 flare peaking at 21:34UT. Catania sunspot group 32 (NOAA active region 2860) remains of beta-gamma magnetic type but seems to tend to shrink and reduce in complexity. It is expected to be the source of further C flaring with still another M flare from this region possible. The other spotted region on disc, Catania group 33 (NOAA active region 2859), is simple and inactive. Another active region is turning onto the disc in the North-East.

There were no new Earth directed CMEs observed in available coronagraph data.

The greater than 10 MeV proton flux was at background levels and we expect it will remain so in the next 24 hours. The greater than 2 MeV electron flux reached again above the 1000 pfu threshold during its diurnal maximum both yesterday and today. The 24h electron fluence is at moderate levels and we expect it to slowly decay and become normal to moderate.

Solar wind did not show any signs of the expected CME arrival (CME of August 26). Solar wind speed was around 400 km/s. Interplanetary magnetic field was around 5nT with a variable Bz. Solar wind conditions may still get enhanced from a possible late arrival of the August 26 CME and then are again expected to be increased on September 2 with the arrival of the August 28 CME.

Geomagnetic conditions were quiet to unsettled (both local K Dourbes and NOAA Kp 1-3). Active conditions are possible in the next 24 hours if the August 26 CME still arrives and later on September 2 with the arrival of the August 28 CME.

Today's estimated international sunspot number (ISN): 037, based on 18 stations.

Solar indices for 30 Aug 2021

Wolf number Catania	035
10cm solar flux	091
AK Chambon La Forêt	014
AK Wingst	008
Estimated Ap	008
Estimated international sunspot number	038 - Based on 21 stations

Noticeable events summary

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

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