Viewing archive of Sunday, 17 September 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Sep 17 1234 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

Quiet (A<20 and K<4)

Solar protons

Quiet

	10cm flux	Ap
17 Sep 2017	070	007
18 Sep 2017	069	007
19 Sep 2017	068	007

Bulletin

The only sunspot group presently observed on the solar disk, Catania number 55 (NOAA AR 2680), is unlikely to produce flaring activity above the B-class level. No flares were reported in the past 24 hours. Newly arrived coronagraph observations show two very faint and slow partial halo CMEs (with angular width of about 180 degrees), first time observed in the SOHO/LASCO C2 field of view at 19:48 UT on September 15 and at 12:24 on September 16. The source region of both CMEs was the Catania sunspot group 46 (NOAA AR 2673) which is at the back side of the Sun as seen from the Earth. Therefore these two CMEs will not arrive to the Earth. The solar protons remained at background level in the past 24 hours.

The Earth remains to be inside the fast solar wind stream associated with a low-latitude extension of the northern polar coronal hole which reached central meridian on September 09. The solar wind speed is slowly decreasing and it presently amounts about 670 km/s. The interplanetary magnetic field magnitude is 6 nT. Due to the influence of the fast flow active geomagnetic conditions were reported in the last 24 hours (both NOAA and local station at Dourbes reported interval of Kp=4 and K=4, respectively). Presently geomagnetic conditions are quiet, however the solar wind speed is still quite high and longer intervals of southward Bz might induce unsettled to active conditions in the coming hours.

Today's estimated international sunspot number (ISN): 015, based on 21 stations.

Solar indices for 16 Sep 2017

Wolf number Catania	///
10cm solar flux	072
AK Chambon La Forêt	034
AK Wingst	025
Estimated Ap	029
Estimated international sunspot number	014 - Based on 25 stations

Noticeable events summary

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

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