Viewing archive of Friday, 16 June 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Jun 16 1242 UTC

SIDC Forecast

Solar flares

Quiet conditions (<50% probability of C-class flares)

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
16 Jun 2017	077	017
17 Jun 2017	078	011
18 Jun 2017	079	014

Bulletin

The only reported flare in the last 24 hours was the B2.9 flare which peaked at 17:00 UT on June 15. There are presently two sunspot groups observed on the visible side of the solar disc, Catania 32 and 33 (NOAA AR 2662 and 2663). The fast evolving Catania sunspot group 33 has presently beta-gamma configuration of its photospheric magnetic field and might be the source of B-class and possibly also isolated C-class flares in the coming hours. No Earth directed CMEs have been observed and the solar protons remained at background level in the past 24 hours.

The in situ observations indicate arrival of the fast solar wind (associated with the large equatorial coronal hole which reached central meridian in the morning of June 13), as expected, in the morning of June 16. At about 03:00 UT this morning the sudden increase of the interplanetary magnetic field (IMF) and the density increase was observed, soon followed with the change of the phi angle.The oscillations of the IMF and its Bz component were followed by sudden increase of the solar wind speed and temperature, and density decrease, marking the interaction region between the slow and fast solar wind. The solar wind speed is presently about 500 km/s and the IMF is about 13nT. Due to the negative value of the Bz component (down to -10nT) and increased solar wind speed (about 550 km/s) active geomagnetic conditions were reported today (Dourbes reported K=4 and NOAA Kp=4). The fast solar wind associated with two large coronal holes (one on the north and one on the south solar hemisphere) which reached central meridian in the evening of June 14 is expected to arrive at the Earth early in the morning of June 18. The geomagnetic conditions are presently active and we expect them to stay so in the coming hours.

Today's estimated international sunspot number (ISN): 031, based on 21 stations.

Solar indices for 15 Jun 2017

Wolf number Catania	035
10cm solar flux	077
AK Chambon La Forêt	009
AK Wingst	006
Estimated Ap	004
Estimated international sunspot number	032 - Based on 34 stations

Noticeable events summary

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

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