Viewing archive of Saturday, 19 September 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Sep 19 1230 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

Quiet

	10cm flux	Ap
19 Sep 2015	104	026
20 Sep 2015	104	026
21 Sep 2015	102	018

Bulletin

NOAA 2415 has lost its delta, but remains magnetically complex. No (zero) C-class flares were observed during the period. The coronal mass ejection (CME) associated to the long duration event on 18 September (C2.6 flare peaking at 06:31UT) was directed to the south of the ecliptic. A glancing blow can not be excluded and could arrive late on 20 or on 21 September.

C-class flares are expected, with a small chance on an M-class flare from NOAA 2415.

Solar wind speed varied mostly between 410 and 450 km/s. Around 03:00UT, a gradual change in solar wind temperature and Bz was observed, accompanied by a mild increase in density and, around 05:00UT, a change in the direction of the interplanetary magnetic field from away to towards the Sun. Bz varied between -8 and +7 nT, being predominantly negative between 05:00 and 09:00UT. Quiet to active geomagnetic conditions were observed in Dourbes, while the Kp-index reached minor storming during the 06-09UT interval. Further data are awaited to pinpoint the source of the observed disturbance.

Quiet to active geomagnetic conditions are expected. Minor geomagnetic storming is still possible on 19 or on 20 September in response to the anticipated arrival of the solar wind stream of the positive transequatorial coronal hole. Late on 20 or on 21 September, the glancing blow of the 18 September CME may arrive at Earth, but currently only active geomagnetic conditions are expected.

Today's estimated international sunspot number (ISN): 061, based on 13 stations.

Solar indices for 18 Sep 2015

Wolf number Catania	///
10cm solar flux	103
AK Chambon La Forêt	026
AK Wingst	012
Estimated Ap	014
Estimated international sunspot number	067 - Based on 25 stations

Noticeable events summary

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

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