Viewing archive of Saturday, 15 August 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Aug 15 1348 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
15 Aug 2015	091	021
16 Aug 2015	089	010
17 Aug 2015	087	008

Bulletin

The only C-class flare reported in the last 24 hours is C1.6 flare, peaking at 12:36 UT today. The flare originated from the NOAA 2401 and was associated with coronal dimming which indicates that there was probably also CME associated with the event. The situation will be clearer as more data will become available in the coming hours. We expect occasional C-class flares in the coming hours.

The partial halo CME, first seen in the SOHO LASCO C2 field of view at 09:36 UT on August 14, was associated with the filament eruption from the south-west quadrant. The CME had the angular width of about 190 degrees and the projected plane of the sky speed of about 300 km/s (as reported by CACTUS software package). The bulk of the CME mass was directed southward of the Sun-Earth line and it is therefore not very probable that this CME will arrive at the Earth. The possible arrival of a CME-driven shock wave might be expected late on August 19 or early morning of August 20 producing at most unsettled geomagnetic conditions.

At 07:30 UT this morning ACE data recorded shock arrival associated with the partial halo CME from August 12. The solar wind speed jumped from 320 to 450 km/s, and the interplanetary magnetic field magnitude reached the value of 28nT. The Bz component of the interplanetary magnetic field had longer interval with the value down to -20nT. This strong southward field produced geomagnetic storm, NOAA reported Kp=7 and Izmiran and Dourbes reported K=5. Currently the interplanetary magnetic field magnitude is about 15nT with the Bz component fluctuating around -10nT. The solar wind speed is about 450 km/s. We expect possibly active geomagnetic conditions in the coming hours.

Today's estimated international sunspot number (ISN): 035, based on 14 stations.

Solar indices for 14 Aug 2015

Wolf number Catania	///
10cm solar flux	093
AK Chambon La Forêt	010
AK Wingst	004
Estimated Ap	003
Estimated international sunspot number	042 - Based on 27 stations

Noticeable events summary

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

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