Viewing archive of Tuesday, 2 September 2014

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2014 Sep 02 1246 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
02 Sep 2014	129	013
03 Sep 2014	132	011
04 Sep 2014	136	005

Bulletin

The strongest flare of the past 24 hours was the C2.6 flare peaking at 00:59 UT today in the Catania sunspot group 40 (NOAA AR 2152). This active region is growing while maintaining the beta-gamma configuration of its photospheric magnetic field. Another active region will appear during the next 24 hours from behind the east-south-east limb. It was the source of several powerful behind-the-limb CMEs yesterday. The solar background X-ray flux increased to above C1 level due to this active region. We expect flaring activity up to the M-level, primarily from the east-south-east limb and perhaps also from the Catania sunspot group 40. The long filament in the northern hemisphere is finishing its crossing of the solar central meridian. It is rising slowly, so its eruption looks imminent now. The resulting CME may be directed towards the Earth. Two partial halo CMEs were detected late yesterday evening. The first halo CME appeared at 21:36 UT in the SOHO/LASCO C2 field of view above the north- west limb, and had angular width around 165 degrees. The position of the CME source region is not entirely clear due to the data gap in the STEREO data, but the absence of CME-associated signatures in the SDO/AIA data (in the north-west quadrant around this time) indicates that the CME originated from the far side of the Sun. The second partial halo CME first appeared at 22:24 UT above the east limb and had angular width around 160 degrees. STEREO B EUVI data indicate that it was associated with a flare (probably an M-class flare) peaking at 22:15 UT in the active region just behind the east-south-east limb (as seen from the Earth). No geomagnetic consequences of these two CMEs are expected. However, the second partial halo CME (perhaps together with yesterday's full halo CME) is most probably associated with the slow rise of the proton flux measured by GOES and ACE since late yesterday evening. We issue a warning condition for a proton event. The Earth is currently inside a slow (around 410 km/s) solar wind flow with average (around 5 nT) interplanetary magnetic field magnitude. We expect quiet geomagnetic conditions.

Today's estimated international sunspot number (ISN): 079, based on 10 stations.

Solar indices for 01 Sep 2014

Wolf number Catania	125
10cm solar flux	127
AK Chambon La Forêt	014
AK Wingst	011
Estimated Ap	013
Estimated international sunspot number	068 - Based on 22 stations

Noticeable events summary

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

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