Viewing archive of Friday, 20 March 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Mar 20 1230 UTC

SIDC Forecast

Solar flares

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

Geomagnetism

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

Solar protons

Quiet

	10cm flux	Ap
20 Mar 2015	109	026
21 Mar 2015	109	017
22 Mar 2015	109	031

Bulletin

Solar activity was low over the period. A long duration C7.9 flare from NOAA active region 2297 peaking at 1:33UT was the only significant event of the period. Only one other low class C flare was recorded originating from the same region. A new region started emerging before UT noon yesterday around N00W70, and seems to evolve rapidly but is of limited concern as it is currently already about to rotate beyond the west limb. The newly emerging region in the northern hemisphere mentioned yesterday was numbered NOAA 2304 and is fairly insignificant. With NOAA regions 2297 and 2302 disappearing beyond the western limb, the most significant potential flaring sources are moving away. Some C flaring may initially still be possible but the C flaring probability is in decline. The long duration C flare was associated with a partial halo CME is visible in SOHO/C2 coronagraph images from 2:00UT onwards. The angular extent of the CME was strongly overestimated by Cactus (wrongly reporting as full halo). At most it reaches an angular extent of 180 degrees. The ejection is predominantly directed westward (the source region located at 90 degrees longitude at the time of the event) with a faint northerly component. It is not expected to have any influence on Earth. Solar wind conditions showed the continued influence of the high speed stream from the southern negative polarity coronal hole, with solar wind speeds in the range of 550-650 km/s. Total magnetic field was between 5 and 8 nT with Bz variable. The magnetic field Phi angle was stable in the negative sector. The influence of the high speed stream is expected to last over the next 24 hours though declining, corresponding to unsettled to active geomagnetic conditions with later quiet to unsettled conditions. A recurrent equatorial coronal hole which is currently passing the central meridian is likely to influence solar wind conditions from March 22, onwards associated with active to minor storm geomagnetic conditions.

Today's estimated international sunspot number (ISN): 017, based on 07 stations.

Solar indices for 19 Mar 2015

Wolf number Catania	///
10cm solar flux	109
AK Chambon La Forêt	038
AK Wingst	024
Estimated Ap	028
Estimated international sunspot number	040 - Based on 17 stations

Noticeable events summary

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

All times in UTC

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