Viewing archive of Wednesday, 21 August 2013

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2013 Aug 21 1240 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Quiet

	10cm flux	Ap
21 Aug 2013	135	018
22 Aug 2013	138	008
23 Aug 2013	138	003

Bulletin

Solar activity was eruptive with a C2.2 flare as strongest flare originating from NOAA AR 1828. A faint partial halo CME was observed in LASCO/C2 around 5h00 UT which was confirmed by STEREO A and B data. It seems to be associated to a small filament eruption located near S15E15, observed in PROBA2/SWAP and GONG H-alpha data. The CME seems to be travelling mainly to the east with a projected speed of 360 km/s. First analysis suggests a possible arrival at 25 August at 9h UT, but this will be further evaluated. We expect C-class flaring activity to continue. There is a slight chance for M-class flares, especially from NOAA active regions 1820 and 1827 that currently have a beta-gamma configuration of their photospheric magnetic field. ACE has observed a jump yesterday at 22h UT in all the plasma parameters jump, but not the magnetic field. This seems to be the arrival of the equatorial CH fast speed stream. Local K-index at Dourbes currently is at K=3 and Kp went up to Kp=4, due to combined effects of the fast speed stream and some influence of a flank of the CME of August 17, that possibly arrived at 2h this morning. Unsettled geomagnetic conditions are expected to continue and return to quiet after 24 hours.

Today's estimated international sunspot number (ISN): 095, based on 13 stations.

Solar indices for 20 Aug 2013

Wolf number Catania	///
10cm solar flux	132
AK Chambon La Forêt	012
AK Wingst	004
Estimated Ap	004
Estimated international sunspot number	086 - Based on 21 stations

Noticeable events summary

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

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