Viewing archive of Saturday, 23 October 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Oct 23 1236 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
23 Oct 2021	092	005
24 Oct 2021	095	006
25 Oct 2021	100	006

Bulletin

Solar activity was at very low levels. The newly numbered NOAA Active Region (AR) 2887, which has rotated onto the south-east of the disk, is a large complex region with beta configuration and has been producing B-level flaring activity. NOAA AR 2886 (Catania sunspot region 64) remained stable. Catania sunspot group 65 also did not develop further. The largest flare of the period was a B9.6 flare that originated from beyond the limb at 18:38 UT. Solar activity is expected to be low over the next 24 hours with C-class flares possible, particularly from NOAA AR2887 and from further ARs expected to rotate onto the solar disk over the coming 24 hours.

A number of Coronal Mass Ejections (CME) were observed originating beyond the eastern limb but are not expected to be Earth-directed. 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 threshold during the next 24 hours. The 24h electron fluence was at nominal levels and is expected to remain so.

The solar wind speed (DSCOVR) decreased from 500 to 390 km/s. The total magnetic field decreased from 5 nT to around 2 nT. The Bz varied between -3 and +4 nT. The interplanetary magnetic field phi angle was predominantly in the negative sector (directed towards from the Sun). The solar wind speed is expected to reflect a slow solar wind regime from Oct 24 as the influence of the high speed stream continues to wane.

Geomagnetic conditions were mostly at quiet levels (NOAA Kp and local K Dourbes recorded values of 1-2 and 0-3, respectively). Geomagnetic conditions are expected to be quiet to unsettled on Oct 23 and Oct 24.

Today's estimated international sunspot number (ISN): 046, based on 22 stations.

Solar indices for 22 Oct 2021

Wolf number Catania	///
10cm solar flux	087
AK Chambon La Forêt	008
AK Wingst	004
Estimated Ap	002
Estimated international sunspot number	037 - Based on 27 stations

Noticeable events summary

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

All times in UTC

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