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:Issued: 2014 Sep 12 1218 UTC
:Product: documentation at http://www.sidc.be/products/presto
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# FAST WARNING 'PRESTO' MESSAGE from the SIDC (RWC-Belgium) #
#--------------------------------------------------------------------#
A shock was observed on 11 September at 23:02UT by ACE. Wind speed abruptly increased from about 350 to 480 km/s. Bz oscillated between -14 and +11nT. This is the impact of the halo CME related to the M4 flare on 9 September. At Dourbes, active geomagnetic conditions were observed (K = 4), while Kp reached minor geomagnetic storm levels.
The CME related to the X1 flare has NOT arrived yet and is expected for later today.
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