Viewing archive of Wednesday, 20 October 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Oct 20 1231 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
20 Oct 2021	076	010
21 Oct 2021	076	011
22 Oct 2021	077	006

Bulletin

Solar activity was at very low levels. NOAA Active Region (AR) 2886 (Catania sunspot region 64) remained stable. A small region of flux emergence was observed to develop near N23E63. Solar activity is expected to be very low over the next 24 hours with a slight probability of C-class flares from NOAA AR 2866.

No Earth directed CMEs have been detected in the available coronagraph imagery.

The greater than 10 MeV proton flux was at nominal levels over the past 24 hours and is expected to remain so for the next 24 hours. The greater than 2 MeV electron flux remained below the 1000 pfu alert threshold and is expected to remain below this level during the next 24 hours. The 24h electron fluence was at nominal levels and is expected to remain so.

The solar wind speed (DSCOVR) ranged between 340 and 430 km/s. The total magnetic field reached a maximum value of 10 nT at the beginning of the period, before then decreasing to around 5 nT. The Bz varied between -8 and +8 nT. The interplanetary magnetic field phi angle was predominantly in the negative sector (directed towards from the Sun). The solar wind speed and magnetic field are expected to continue to be slightly enhanced on Oct 20 and 21, due to the influence of the High Speed Stream (HSS) associated with the with the negative polarity extension of the southern polar CH which began to cross the central meridian on Oct 16.

Geomagnetic conditions reached active levels (NOAA Kp and local K Dourbes recorded values of 1-4) over the past 24 hours. Geomagnetic conditions are expected to be unsettled to active on Oct 20 and 21, due to the influence of the aforementioned HSS and returning to quiet to levels from Oct 22.

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

Solar indices for 19 Oct 2021

Wolf number Catania	011
10cm solar flux	076
AK Chambon La Forêt	020
AK Wingst	017
Estimated Ap	016
Estimated international sunspot number	011 - Based on 18 stations

Noticeable events summary

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

All times in UTC

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