Viewing archive of Sunday, 21 June 2015

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2015 Jun 21 1230 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

Minor storm expected (A>=30 or K=5)

Solar protons

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

	10cm flux	Ap
21 Jun 2015	135	027
22 Jun 2015	133	071
23 Jun 2015	131	063

Bulletin

Solar flaring activity was moderate with an M4.0 flare from Catania group 87 (NOAA region 2367) peaking at 9:44 UT and a double M2 flare from Catania group 92 (NOAA region 2371). The latter peaked at M2.0 level at 1:42UT and at M2.6 level at 2:35UT. It was associated with a dimming and a corresponding full halo was observed in SoHO/LASCO images. Solar flaring at M level is likely over the next days by both regions on disk, which are now on or approaching the western hemisphere. The 10 MeV proton flux was at decline towards background levels but stabilized around 18:00UT at slightly elevated levels of around 0.7 pfu. Since 2:00UT the level is gently rising again to current levels of 2-3 pfu. This is likely to increase further and a warning condition is issued for the coming days. The full halo CME associated to the double peaked M2 flare from Catania group 92 (NOAA region 2371) located just east off the central meridian (about -13 degrees at the time of the event), has its first appearance in SoHO/LASCO C2 images at 2:36UT. The halo is fairly symmetric with principle direction only slightly northeast (CACTUS software erroneously interpreted the event as three separate events with limited angular extent). Measured projected speeds are around 1000-1300 km/s. This CME is definitely earthbound and may interact with the June 19 CME. A combined arrival of those is expected from June 22 afternoon onwards. Solar wind is still at nominal levels with the speed and total magnetic field dropping further to low values of 280 km/s and 2nT respectively. Bz was variable in the +-1.5 nT range. Corresponding quiet to unsettled geomagnetic conditions were recorded (NOAA Kp 0-1, local K Dourbes 0-3). Solar wind conditions are expected to become perturbed later today by a glancing blow from the June 18 CME, followed by the arrival of another glancing blow from the June 19 CME and the arrival of the June 21 CME from the afternoon of June 22 onwards. Minor to moderate geomagnetic storms may occur later today and tomorrow with possibly major to severe storms late June 22 and June 23 associated to the arrival of the June 21 CME.

Today's estimated international sunspot number (ISN): 046, based on 10 stations.

Solar indices for 20 Jun 2015

Wolf number Catania	///
10cm solar flux	135
AK Chambon La Forêt	006
AK Wingst	002
Estimated Ap	003
Estimated international sunspot number	048 - Based on 20 stations

Noticeable events summary

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

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