FAST WARNING 'PRESTO' MESSAGE from the SIDC (RWC-Belgium) 2015 Apr 21 21:21:17
An asymmetric full halo with primary north-east direction is visible in SoHO/LASCO C2 coronagraph images from 10:36 UT April 21 onwards. The event actually comprises of three consecutive events. At 10:25UT SDO/AIA images show a darkening at the north-east limb. The opening fieldlines appear to be originating from behind the limb. The consecutive post-flare arcades are visible at the limb and are the source of the M2.2 flare with peak time 10:40UT reported earlier. At 11:48 the SoHO/LASCO C2 coronagraph images show a second CME departing the west limb, again with no clearly identifiable on disc source although it appears to coincide with (though slightly preceding) the M2.2 flare observed from Catania group 28 (NOAA region 2322) close to the West limb. This second event is much less powerful than the first but adds to the apparent angular width and together with the first event they display an apparent full halo character. Following the M2.2 flare at the north-east limb, a third eruption is visible in the coronagraph data from 13:36 UT onwards. The eruption is also clearly visible in SDO/AIA 304 images, showing it to originate from the visible side of the Sun, although very close to the limb. This third CME appears as fairly narrow in the coronagraph images. All in all, given the location of origin of the CME's, none of these events is expected to have any influence at Earth location.