Viewing archive of Thursday, 11 April 2013

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2013 Apr 11 1227 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Severe geomagnetic storm expected (A>=100 or K>=7)

Solar protons

Proton event in progress (>10 MeV)

	10cm flux	Ap
11 Apr 2013	150	009
12 Apr 2013	147	009
13 Apr 2013	145	080

Bulletin

Seven sunspot groups are reported by Catania today. Catania sunspot groups 40 and 43 (NOAA ARs 1718 and 1719 respectively) maintain beta-gamma configuration of the photospheric magnetic field. C-class and M-class flares are likely to erupt from at least one of these active regions, with a small chance for an X-class flare (especially from Catania sunspot group 43, NOAA AR 1719). An M6.5 flare peaking at 07:16 UT was detected today in the Catania sunspot group 43 (NOAA AR 1719), accompanied by a metric type II burst observed by Humain starting from around 07:02 UT. SDO/AIA data demonstrate that this flare was also accompanied by coronal dimmings, an EIT wave, and a post-eruption arcade, indicating the eruption of a CME. A full halo CME was first detected in the SOHO/LASCO C2 field of view at 07:24 UT. The CME plane-of-the-sky linear speed was around 930 km/s (the second-order fit showed deceleration from around 1160 km/s to 800 km/s as the CME progressed through the C2 and C3 fields of view). The corresponding interplanetary disturbance is expected to arrive at the Earth in the morning of April 13. Due to the position of the CME source region (Catania sunspot group 43, NOAA AR 1719) close to the solar disk center (around N09E12), the arrival of the magnetic cloud is possible, even if the CME presented a strong asymmetry of the material distribution towards the east. If present, the magnetic cloud will most probably have left-handed chirality, with WSE or NWS magnetic field orientations. The occurrence of a strong geomagnetic storm (K index around 7) will be probable. The proton flux at energies above 10 MeV crossed the SEP event threshold around 10:00 UT and is still rising at the time of writing. The Earth is currently inside a slow (around 420 km/s) solar wind flow with slightly elevated (5-6 nT) interplanetary magnetic field magnitude. We expect quiet geomagnetic conditions in the coming hours.

Today's estimated international sunspot number (ISN): 079, based on 08 stations.

Solar indices for 10 Apr 2013

Wolf number Catania	///
10cm solar flux	148
AK Chambon La Forêt	010
AK Wingst	006
Estimated Ap	005
Estimated international sunspot number	099 - Based on 11 stations

Noticeable events summary

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

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