Viewing archive of Saturday, 21 October 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Oct 21 1237 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Quiet

	10cm flux	Ap
21 Oct 2017	077	017
22 Oct 2017	077	007
23 Oct 2017	077	007

Bulletin

From the East limb, returning NOAA region 2682 produced a long duration M1.1 flare peaking at 23:28 UT on October 20. An associated dimming was detected by Solar Demon, and an associated Type II radio burst was observed by Palehua at 23:35 UT with a corresponding speed of 344 km/s. SOHO LASCO C2 and C3 and STEREO COR2 A have observed an associated bright CME, first seen in LASCO C2 at 00:00 UT on October 21, from the northeast to the southeast. Analysis of COR2 A jplots revealed a plane of sky speed of about 385 km/s, yielding a full speed of 770 km/s. Due to the position of the source, this CME will not be geoeffective. C flares are likely in the next 24 hours (70% probability), with a chance for an M flare (30% probability). No Earth-directed Coronal Mass Ejections (CMEs) were observed in available coronagraphic imagery. The greater than 10 MeV proton flux was at nominal levels. A small, fast forward shock in the solar wind occurred at 5:16 UT on October 21. Solar wind speed registered by DSCOVR jumped from about 340 to 365 km/s, while the magnitude of the Interplanetary Magnetic Field (IMF) jumped from about 4 to 6 nT. Current solar wind speed is about 360 km/s and current IMF magnitude is about 8.5 nT. The IMF was directed away from the Sun until it started pointing towards the Sun around 7:40 UT on October 21. Quiet to unsettled conditions (K Dourbes between 1 and 3; NOAA Kp between 1 and 2) were registered in the past 24 hours. There is a chance for active geomagnetic levels (K Dourbes = 4) on October 21. Quiet to unsettled geomagnetic levels (K Dourbes < 4) are expected on October 22 and 23.

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

Solar indices for 20 Oct 2017

Wolf number Catania	000
10cm solar flux	076
AK Chambon La Forêt	012
AK Wingst	010
Estimated Ap	010
Estimated international sunspot number	000 - Based on 26 stations

Noticeable events summary

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

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