Viewing archive of Thursday, 27 August 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Aug 27 1232 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

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

	10cm flux	Ap
27 Aug 2015	128	037
28 Aug 2015	130	028
29 Aug 2015	130	015

Bulletin

Solar flaring activity was moderate with an M2.9 flare peaking 5:44 UT from region 2403. The region produced also a C9.5 flare earlier in the period, peaking at 13:53UT which was related with a dimming and filament eruptions to the North of the region. Corresponding ejecta are seen in SoHO/LASCO C2 data on the West limb around 20:36, but seem insignificant. Region 2403 remains complex and may be the source of further M-flaring with a slight chance for an X flare. Meanwhile two new regions are also rotating onto the Eastern hemisphere but their flaring potential appears low. The warning condition for proton events in relation to AR 2403 is maintained. No Earth directed CME's were observed in coronagraph data. Solar wind saw a further decline of the solar wind speed from around 400 km/s to around 360 km/s. The already elevated total magnetic field (10 nT at the start of the period) reached peaks of around 14nT this morning. Along with sustained periods of pronounced negative Bz this caused associated minor to moderate geomagnetic storm conditions since afternoon/late August 26. While local K Dourbes reported only active conditions to minor storm conditions, the planetary NOAA Kp reached moderate storm conditions (Kp=6) for the 3-6 and 6-9UT intervals. The origin of the elevated magnetic field values is not very clear. While a corotating interaction region (CIR) was expected later today, the signatures of magnetic field rotation, low temperatures and declining speed profile are more indicative of an ICME preceding the expected CIR. After the passage of the expected CIR solar wind speeds are expected to rise due to coronal hole high speed stream influence. Thus, solar wind conditions are in any case expected to remain elevated and active to moderate storm conditions are expected to continue over the next day subject to solar wind magnetic field orientation.

Today's estimated international sunspot number (ISN): 063, based on 11 stations.

Solar indices for 26 Aug 2015

Wolf number Catania	///
10cm solar flux	126
AK Chambon La Forêt	053
AK Wingst	037
Estimated Ap	036
Estimated international sunspot number	044 - Based on 32 stations

Noticeable events summary

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

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