Viewing archive of Wednesday, 21 October 2020

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2020 Oct 21 1239 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
21 Oct 2020	075	013
22 Oct 2020	074	023
23 Oct 2020	075	007

Bulletin

Solar flaring activity is low. Catania group 45 (NOAA AR 2776 - alpha classification) is very gradually decaying as is crossing the solar disk. It was the source of B1.3-class flare on Oct 20 13:18UT. A B3.5 flare originated from a small region on the north western limb. A new region has appeared on the north eastern part of the visible disk. NOAA AR 2776 can be the source of further more low A and possibly B-class flares in the coming hours.

No Earth directed Coronal Mass Ejections (CMEs) were observed in the available coronagraphic imagery.

The greater than 10 MeV proton flux was at background levels over the past 24 hours. It is expected to stay at background levels for the next 24 hours. The greater than 2 MeV electron flux was at nominal levels over the past 24 hours. It is expected to remain at those levels over the next 24 hours.

Taking into account there was a lack of data from multiple instruments between the time from Oct 21 00:50UT to Oct 21 07:51UT, the following conditions of the solar wind can be reported. The speed of the solar wind decreased slightly, varying between 345 and 430 km/s (DSCOVR). Temperature and density decreased compared to the values 24 hours ago, but the latest data indicate an increase. The polarity of the Interplanetary Magnetic Field (IMF) varied, currently pointing towards the Sun (phi angle in the negative sector). Bz fluctuated between -4 and +5 nT. The magnitude of the magnetic field varied between 1 and 10 nT. The conditions could associated with the high speed streams originating from the Coronal Holes (CH) crossing of Central Meridian (CM) on Oct 16 and 17, while the current extensions of the northern CH could explain the varying phi angle. Similar conditions are expected in the coming hours.

The geomagnetic conditions were quiet to unsettled, with an active period that started Oct 21 6:00UT (Kp=4). This could be associated with the HSS from the CHs crossing CM Oct 16 and 17. The values registered for the past 24 hours were 0-3 for K Dourbes and 0-4 for NOAA Kp. Quiet to unsettled conditions, with a possibility of active conditions, are expected for the next 24 hours, reflecting the HSS from the CHs crossing CM the past days.

Today's estimated international sunspot number (ISN): 011, based on 14 stations.

Solar indices for 20 Oct 2020

Wolf number Catania	016
10cm solar flux	075
AK Chambon La Forêt	008
AK Wingst	006
Estimated Ap	004
Estimated international sunspot number	012 - Based on 14 stations

Noticeable events summary

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

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