Viewing archive of Friday, 29 October 2021

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2021 Oct 29 1249 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Proton event in progress (>10 MeV)

	10cm flux	Ap
29 Oct 2021	112	003
30 Oct 2021	105	007
31 Oct 2021	095	017

Bulletin

Solar flaring activity was high during the last 24 hours, with one X1 flare detected from NOAA Active Region (AR) 2887 on 28 Oct 15:48 UT. An M1 flare was produced by NOAA AR 2891 today with a peak at 02:53 UT. Those two ARs were responsible for numerous C-class flares during the last 24 hours. Several other ARs appear on disk, but did not produce any noticeable activity. NOAA AR 2887 is likely to produce M-class flare activity and NOAA AR 2891 might also produce flares at the M-class level in the next 24 hours. Another X-class flare from NOAA AR 2887 might take place during the next 24 hours.

A halo Coronal Cass Ejection (CME) was detected by CACTUS from SOHO/LASCO-C2 images. It was caused by an eruption that took place on 27 Oct 15:50 UT close to the solar central meridian and in the solar south hemisphere. Based on STEREO/COR2 measurements, Its speed is estimated to be around 800 km/s. As such it is almost certainly geo-effective and its arrival time is estimated to be in the early UT hours of the 31 Oct.

The greater than 10 MeV proton flux increased above nominal levels during the past 24 hours most likely because of the CME mentioned above. It went above the threshold of 10 particles cm-2 s-1 sr-1 on 28 Oct 17:35 UT and peaked at 30 particles cm-2 s-1 sr-1 today around 02:50 UT. The event is still on-going and it is expected to end within 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 typical of the slow SW regime for the past 24 hours. The SW speed (as measured by DSCOVR) varied between 280 and 310 km/s during the last 24 hours. The total magnetic field (Btot) was at low levels, between 1 and 6 nT, while its Bz component varied between -2 and 4 nT in the last 24 hours. The interplanetary magnetic field phi angle was almost exclusively in the negative sector (directed towards the Sun) during the last 24 hours. The solar wind conditions are expected to remain in the slow solar wind regime for the next 24 hours, unless the ICME predicted to arrive on 31 Oct, becomes geo-effective much earlier.

Geomagnetic conditions were globally and locally quiet (NOAA Kp and K Dourbes 0-2). Geomagnetic conditions are expected to remain quiet for the next 24 hours.

Today's estimated international sunspot number (ISN): 077, based on 22 stations.

Solar indices for 28 Oct 2021

Wolf number Catania	///
10cm solar flux	112
AK Chambon La Forêt	003
AK Wingst	000
Estimated Ap	002
Estimated international sunspot number	092 - Based on 30 stations

Noticeable events summary

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

All times in UTC

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