Viewing archive of Monday, 17 September 2018

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2018 Sep 17 1245 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 2018	068	011
18 Sep 2018	067	010
19 Sep 2018	067	008

Bulletin

During last 24 hours solar activity was low with no C-class and even B-class flares reported. The only sunspot group observed on the visible side of the solar disc, Catania sunspot group 95 (NOAA AR 2722), has strongly decayed. The probability for this sunspot group to be source of the flaring activity is low. We do not expect C-class flares in the coming hours, and even the probability for B-class flares is rather low. Presently available coronagraph images do not show signatures of the Earth directed CMEs, and the solar protons are at the background level.

The in situ observations indicate arrival of the fast solar wind associated with the equatorial coronal hole having large extension on the southern solar hemisphere (coronal hole reached central meridian in the evening of September 13). The solar wind speed is presently about 510 km/s and the interplanetary magnetic field magnitude is about 10 nT. The Bz component of the interplanetary magnetic field was mostly positive therefore the geomagnetic conditions were so far quiet to unsettled. We expect such a geomagnetic conditions to persist in the coming hours. If the Bz component turns to negative values, isolated intervals of active geomagnetic conditions are possible.

Today's estimated international sunspot number (ISN): 012, based on 19 stations.

Solar indices for 16 Sep 2018

Wolf number Catania	///
10cm solar flux	069
AK Chambon La Forêt	015
AK Wingst	007
Estimated Ap	005
Estimated international sunspot number	000 - Based on 26 stations

Noticeable events summary

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

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