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Daily bulletin on solar and geomagnetic activity from the SIDC

Emesso: 2017 Sep 18 1242 UTC

SIDC Forecast

Brillamenti solari

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

Geomagnetism

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

Protoni solari

Quiet

	10cm flux	Ap
18 Sep 2017	073	022
19 Sep 2017	073	008
20 Sep 2017	073	007

Bulletin

Over the past 24 hours the Earth side solar activity was very low and no flaring activity has been recorded. The only region presented on the Earth side disk, Catania sunspot group 55 (NOAA region 2680), has declining and is unlikely to produce any flaring activity above the B-class level. The solar activity on the back side is more active with several coronal mass ejections (CME) observed in SOHO/LASCO coronagraph. More back-side CMEs can be expected, including halo CME as the very active Catania group 46 (NOAA region 2673) is located close to the center.

No Earth directed CMEs have been observed and the solar protons remained at background level in the past 24 hours.

The Earth remained in the fast solar wind with a speed around 600 and 700 Km/s, associated with a low-latitude extension of the northern polar coronal hole which reached central meridian on September 09. The interplanetary magnetic field magnitude remained between 5 and 6 nT, and the Bz component fluctuating between -6 and 5 nT being mainly negative.

Disturbed geomagnetic conditions were observed with K-Dourbes up to 4 and Kp-NOAA up to 5 due to the fast solar wind and the southward Bz component of the interplanetary magnetic field over several consecutive intervals. The geomagnetic conditions are expected to vary between unsettled to active conditions and even minor storm conditions may be observed in the coming hours, in particular, if the Bz component stays negative for longer periods. We expect quiet to unsettled geomagnetic conditions as the high speed stream will decrease.

Today's estimated international sunspot number (ISN): 014, based on 22 stations.

Solar indices for 17 Sep 2017

Wolf number Catania	///
10cm solar flux	072
AK Chambon La Forêt	030
AK Wingst	016
Estimated Ap	019
Estimated international sunspot number	015 - Based on 28 stations

Noticeable events summary

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

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