Viewing archive of Friday, 26 September 2014

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2014 Sep 26 1231 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
26 Sep 2014	162	011
27 Sep 2014	167	012
28 Sep 2014	167	007

Bulletin

Solar activity has been low but increasing. A number of C flares have been recorded from the regions 2175, 2171 and 2172. The largest one peaked at 5:44 UT at a C8.6 magnitude and is attributed to AR 2175 but is likely to carry contributions from all three mentioned regions. Renewed flux emergence at the trailing side of region 2171 caused a C3.2 flare peaking at 20:32 UT and was associated with a filament lift off around 20:38 UT. However, no associated CME could be identified in coronagraph data. Another C5.6 flare peaked at 22:09 UT from region 2175. With these three regions 2175, 2171 and 2172 experiencing further growth, M flare probabilities are rising. We expect C flares with a fair probability for M class flares and a slight chance for X flaring. The partial halo CME with first detection in SOHO/LASCO C2 at 4:28 (and corresponding Cactus alert) is a backside event. It is predominantly directed eastward and is associated with a filament eruption that in SDO/AIA images can clearly be seen to depart from behind the east limb. STEREO B EUVI 195 images show it to be originating from the same active region that has produced multiple (partial) halo CME's over the past days. The region will be turning around the east limb onto the visible disc in a couple of days. Solar wind speed was fairly stable around 450 km/s within the 410-485 km/s range. Total magnetic field was around 6 nT with a peak of 7 nT. Bz was variable in the +-6nT range. Geomagnetic conditions were quiet to unsettled (NOAA Kp 2-3, local K Dourbes 1-3). Similar conditions are expected to continue with still active geomagnetic conditions possible.

Today's estimated international sunspot number (ISN): 113, based on 07 stations.

Solar indices for 25 Sep 2014

Wolf number Catania	///
10cm solar flux	158
AK Chambon La Forêt	022
AK Wingst	014
Estimated Ap	016
Estimated international sunspot number	105 - Based on 26 stations

Noticeable events summary

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

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