:Issued: 2025 Dec 07 1256 UTC
:Product: documentation at http://www.sidc.be/products/presto
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# FAST WARNING 'PRESTO' MESSAGE  from the SIDC (RWC-Belgium)         #
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A halo coronal mass ejection (SIDC CME 605) was first detected in the LASCO/C2
imagery starting at 19:24 UTC on Dec 06 and visible to the north-east in STEREO at
20:38 UTC. The CME is associated to the M-flaring from SIDC Sunspot Group 687 (NOAA
Active Regions 4274, 4299). Related type II and type IV radio emissions were
registered at 20:40 UTC and 20:57 UTC on Dec 06, respectively, and a large coronal
dimming with post-eruptive arcade was detected as well. The CME has an estimated
velocity of 850 km/s and is directed predominantly to the north-east. Preliminary
analysis suggests a possible arrival at Earth late UTC on Dec 08 to early Dec 09.
Small enhancements in the proton flux was registered related to the M-class flaring,
but no proton events were observed and the greater than 10 MeV GOES proton flux has
remained below 10 pfu. Further enhancements of the proton flux are possible in case
of new strong flaring activity and there are chances for mild particle acceleration
from the observed halo CME.
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