Viewing archive of Wednesday, 23 September 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Sep 23 1230 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
23 Sep 2015	105	009
24 Sep 2015	107	021
25 Sep 2015	104	011

Bulletin

Five sunspot groups are reported by Catania today. Four C-class flares were detected during the past 24 hours (all four this morning), the strongest one being the C2.9 flare peaking at 07:30 UT in the Catania sunspot group 31 (NOAA AR 2415) that is currently located just behind the West solar limb. We expect flaring activity on the C-level, with a small chance for an M-class flare, in particular from a newly emerged Catania sunspot group 39 (NOAA AR 2422) that already produced a C1.2 flare today. A slow partial halo CME (angular width around 160 degrees) first appearing in the SOHO/LASCO C2 field of view at 07:24 UT on September 22 is a backside event and will not arrive at the Earth. An Earth-directed CME is possible in case of an eruption of a filament in the south-east quadrant of the solar disk that is currently approaching the solar central meridian. The Earth is currently inside a solar wind flow with intermediate speed (around 500 km/s). The interplanetary magnetic field (IMF) magnitude is slightly elevated in the past several hours (up to 9 nT), but the north- south IMF component Bz is fluctuating. The geomagnetic conditions are on the quiet to unsettled levels and are expected to remain so in the coming hours. Active to minor storm geomagnetic conditions are possible tomorrow due to the arrival of the fast solar wind flow from a small equatorial coronal hole.

Today's estimated international sunspot number (ISN): 089, based on 10 stations.

Solar indices for 22 Sep 2015

Wolf number Catania	086
10cm solar flux	107
AK Chambon La Forêt	///
AK Wingst	011
Estimated Ap	011
Estimated international sunspot number	077 - Based on 24 stations

Noticeable events summary

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

All times in UTC

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