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Daily bulletin on solar and geomagnetic activity from the SIDC

Emesso: 2017 Apr 05 1230 UTC

SIDC Forecast

Brillamenti solari

C-class flares expected, (probability >=50%)

Geomagnetism

Quiet (A<20 and K<4)

Protoni solari

Warning condition (activity levels expected to increase, but no numeric forecast given)

	10cm flux	Ap
05 Apr 2017	091	004
06 Apr 2017	089	005
07 Apr 2017	087	005

Bulletin

Solar activity was at low levels during the period. Flaring activity decreased as NOAA 2644 rounded the west limb. NOAA 2645 produced most of the flaring, including a C4.9 event peaking at 23:42UT, the strongest event of the period. This region still has a complex magnetic trailing portion. The 10.7cm radio flux dropped from 108 sfu on 3 April to 94 sfu on 4 April. No earth-directed coronal mass ejections (CMEs) were observed in available coronagraphic imagery. The greater than 10MeV proton flux was at nominal levels.

Mostly C-class flaring is expected, with a chance on an isolated M-class flare. A major flare from NOAA 2645 may drive the proton levels above event threshold.

During the first half of the period, solar wind speed was somewhat enhanced with speeds around 470 km/s. This may be the brief and weak influence of the moderate speed stream from the positive equatorial coronal hole (CH). Solar wind speed was near 410 km/s during the second half of the period. Bz was mostly positive, fluctuating between +13 and -6 nT. Total magnetic field strength B was in a generally declining trend, from 16 to 5 nT. The direction of the interplanetary magnetic field was variable, pointing towards the Sun by the end of the period.

The geomagnetic field was at quiet to unsettled levels, and is expected to remain so. There's a small chance on an active episode.

Today's estimated international sunspot number (ISN): 054, based on 21 stations.

Solar indices for 04 Apr 2017

Wolf number Catania	///
10cm solar flux	094
AK Chambon La Forêt	018
AK Wingst	016
Estimated Ap	018
Estimated international sunspot number	079 - Based on 33 stations

Noticeable events summary

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

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