Viewing archive of Saturday, 30 October 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Oct 30 1230 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Quiet

	10cm flux	Ap
30 Oct 2021	111	026
31 Oct 2021	108	034
01 Nov 2021	105	017

Bulletin

Solar flaring activity was low during the last 24 hours, with four 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 two. NOAA AR 2887 was very quiet when compared to its activity on 28 Oct and considering its magnetic complexity. Hence, an increase in activity is expected for the next 24 hours, with a fair chance of an M-class flare and a small chance for another X-class flare. NOAA AR 2891 is expected to continue producing a small number of C-class flares in the next 24 hours.

No Earth-directed Coronal Mass Ejections (CMEs) can be seen in the available corona images. A CME detected by CACTUS and seen in SOHO/LASCO-C2 images erupted on 29 Oct 18:40 UT, but it is located on the western edge of the visible solar disk and it not expected to be geo-effective.

The greater than 10 MeV proton flux as measured by GOES-16 remained above nominal levels in the last 24 hours. It is expected to drop below the 10 particles cm-2 s-1 sr-1 in the next 24 hours, unless another proton event occures. 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 (as measured by DSCOVR) varied was very low, between 280 and 340 km/s during the last 24 hours. The total magnetic field decreased from 2 nT to 8 nT, while the Bz varied between -6 and +5 nT in the last 24 hours. The interplanetary magnetic field phi angle was predominantly in the negative sector (directed towards the Sun) during the last 24 hours. However, those conditions are expected to change drastically in the next 24 hours, as a fast Interplanetary Coronal Mass Ejection (ICME) is expected to reach Earth. The ICME is expected to be headed by a shock that will change rapidly several solar wind parameters.

Geomagnetic conditions were globally and locally quiet (NOAA Kp and K Dourbes 1-2). However, A fast ICME is expected to arrive later today and increase the K indeces to at least minor storm conditions.

Today's estimated international sunspot number (ISN): 069, based on 08 stations.

Solar indices for 29 Oct 2021

Wolf number Catania	///
10cm solar flux	108
AK Chambon La Forêt	008
AK Wingst	002
Estimated Ap	002
Estimated international sunspot number	072 - Based on 25 stations

Noticeable events summary

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

All times in UTC

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