Viewing archive of Sunday, 31 October 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Oct 31 1242 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
31 Oct 2021	110	007
01 Nov 2021	108	001
02 Nov 2021	103	001

Bulletin

Solar flaring activity was low during the last 24 hours, with seven C-class flares detected from two Active Regions (ARs). More specifically, NOAA AR 2887 produced two C-class flares and NOAA AR 2891 produced the remaining five. NOAA AR 2887 has now lost a significant portion of its magnetic complexity and is not expected to produce any X-class flares. There is a reduced but significant chance for an isolated M-class flare and the C-class flare activity is expected from this AR for the next 24 hours. NOAA AR 2891 is expected to continue its C-class flare activity, with a small chance of an M-class flare, in the next 24 hours.

No Earth-directed Coronal Mass Ejections (CMEs) can be seen in the available corona images.

The greater than 10 MeV proton flux as measured by GOES-16 dropped below nominal levels during the last 24 hours. It is expected to remain below this level 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 (SW) conditions were affected by an Interplanetary Coronal Mass Ejection (ICME) that arrived around 30 Oct 17:00 UT, as predicted. The SW speed increased from a background value of 310 km/s to 460 km/s during the last 24 hours. The total magnetic field varied between 2 and 13 nT, while the Bz varied between -11 and +8 nT in the last 24 hours. The interplanetary magnetic field phi angle was predominantly in the positive sector (directed away from the Sun) during the last 24 hours. The electron temperature increased from a background level of approximately 20000 K to 100000 K during the last 24 hours. Since the ICME arrival had a relatively small impact, geomagnetic conditions are expected to gradually return to a slow wind regime during the next 24 hours.

Geomagnetic conditions were globally and locally quiet to moderate (Kp and K Dourbes indeces 1-4). The moderate levels were the result of the expected ICME that arrived around 30 Oct 17:00 UT. However the impact of its arrival is relatively small and short-lived, hence the geomagnetic conditions are expected to be quiet for the next 24 hours.

Today's estimated international sunspot number (ISN): 063, based on 15 stations.

Solar indices for 30 Oct 2021

Wolf number Catania	///
10cm solar flux	107
AK Chambon La Forêt	017
AK Wingst	010
Estimated Ap	010
Estimated international sunspot number	073 - Based on 17 stations

Noticeable events summary

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

All times in UTC

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