Viewing archive of Tuesday, 12 September 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Sep 12 1239 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Proton event in progress (>10 MeV)

	10cm flux	Ap
12 Sep 2017	079	015
13 Sep 2017	078	018
14 Sep 2017	077	006

Bulletin

Solar activity is rather low with only one C-class flare reported in the last 24 hours. The C3.0 flare (peaked at 07:49 UT today), originated from the Catania sunspot group 55 (NOAA AR 2680), and was associated with the shock wave (type II radio burst was reported by HUMAIN station). Altgouh coronagraph data are not yet available, the presence of the on-disc CME signatures, EIT wave and coronal dimming, indicate that the flare was associated with the CME. More will be reported when coronagraph data become available. We expect isolated C-class flares in the coming hours. The particle event, associated with the X8.2 flare is still on going, but the level of the proton fluxes is slowly decreasing, and presently only fluxes with >10 MeV, > 50 MeV are above the event threshold. The Earth is presently inside the slow solar wind with the speed of about 460 km/s and the interplanetary magnetic field magnitude is about 4 nT. The CME-driven shock wave, associated with the X8.2 flare reported on September 10, still might arrive at the Earth in the coming hours. The fast solar wind, associated with the low latitude coronal hole in the northern hemisphere which reached the central meridian on September 10, is expected to arrive at the Earth in the mid-day tomorrow, September 13. We expect unsettled to active conditions within next 24 hours due to arrival of the CME-driven shock wave and the fast solar wind.

Today's estimated international sunspot number (ISN): 012, based on 23 stations.

Solar indices for 11 Sep 2017

Wolf number Catania	034
10cm solar flux	080
AK Chambon La Forêt	016
AK Wingst	014
Estimated Ap	013
Estimated international sunspot number	030 - Based on 29 stations

Noticeable events summary

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

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