Viewing archive of Friday, 28 July 2017

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2017 Jul 28 1230 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
28 Jul 2017	069	007
29 Jul 2017	069	003
30 Jul 2017	072	008

Bulletin

Solar activity was at very low levels, and is expected to remain so. A barely visible sunspot group (Catania 40) is trying to develop at location N19W01. No earth-directed coronal mass ejections (CMEs) were observed in available coronagraphic imagery. The greater than 10 MeV proton flux remained slightly above background levels.

A partial halo CME was detected by CACTus on 28/05:36UT July emanating from behind the northeast limb with a plane-of-the-sky speed near 600 km/s. The source is old active region NOAA 2665 which is currently on the Sun's farside and expected to round the east limb on 31 July. The CME is not directed to Earth, but STEREO-A is likely to be impacted.

Solar wind speed varied steadily between 430-450 km/s until 06UT, when it shifted up to a range between 450 and 490 km/s (DSCOVR). Bz oscillated between -6 and +5 nT during the entire period. The interplanetary magnetic field was mostly directed away from the Sun. A small negative equatorial coronal hole (CH) is transiting the central meridian.

The geomagnetic field was at quiet to unsettled levels, and is expected to remain so. The particle stream associated with the aforementioned CH may start influencing the earth environment late on 30 or on 31 July, with active geomagnetic conditions possible.

Today's estimated international sunspot number (ISN): 000, based on 15 stations.

Solar indices for 27 Jul 2017

Wolf number Catania	000
10cm solar flux	068
AK Chambon La Forêt	012
AK Wingst	008
Estimated Ap	007
Estimated international sunspot number	000 - Based on 25 stations

Noticeable events summary

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

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