Viewing archive of Thursday, 25 September 2014

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2014 Sep 25 1232 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
25 Sep 2014	150	013
26 Sep 2014	155	016
27 Sep 2014	160	010

Bulletin

Solar activity has been low, with just a couple of C flares. The strongest one originating, as expected, from NOAA AR 2172, peaking at 17:50 UT at C7 level. A new region (NOAA unnumbered) has emerged with current location near N15W00 developing fast both in size and complexity. This region certainly adds to the expected C flaring from NOAA AR 2172 as well as to the M flare potential. We thus expect flaring on the C level with the chance for M flares increasing further, depending on the new region development. With the filament situated closely to the west of the new region, further development of this region may also lead to the destabilization and eruption of that filament in the following days. An asymmetric halo CME is visible in SOHO/LASCO C2 coronagraph images from 21:12 UT onwards. It is primarily directed northward. Despite the main eruption taking place within a data gap, STEREO B/EUVI 195 images indicate that the eruption originated from NOAA AR 2158. The event is thus backsided and very similar to the September 22, 6:25UT event. Solar wind speed rose slightly from about 420 km/s to around 450 km/s. After reaching a peak of 8.5 nT around 18:00 UT total magnetic field decreased to around 6.5 nT currently. Bz reached negative peaks of over -7nT around 18:00 UT but is currently within a more restricted range of about +-4nT. Unsettled geomagnetic conditions with active periods have been recorded over the reporting period (NOAA Kp as well as local K Dourbes 3-4) settling locally to quiet conditions more recently (local K Dourbes 1-2 after 3:00 UT). Solar wind conditions are expected to remain slightly enhanced over the next days with periods of active geomagnetic conditions possible.

Today's estimated international sunspot number (ISN): 103, based on 17 stations.

Solar indices for 24 Sep 2014

Wolf number Catania	///
10cm solar flux	145
AK Chambon La Forêt	032
AK Wingst	024
Estimated Ap	026
Estimated international sunspot number	073 - Based on 17 stations

Noticeable events summary

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

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