:Issued: 2026 May 04 2306 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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The in situ solar wind parameters as measured by ACE at L1 have registered the
signature of a solar wind transient seemingly indicating the onset of an ICME arrival
starting around 14:55 UTC on May 04. The ICME possibly relates to one of two faint
and slow coronal mass ejections (CMEs) observed in the SOHOS/LASCO C2 field of view
around 12:30 UTC and 18:30 UTC on Apr 30. At present the magnitude of the
interplanetary magnetic field has increased to 11 nT and continues to rise. The
north-south Bz component has reached a minimum of - 10.5 nT. The solar wind speed
remains slow below 470 km/s. The corresponding geomagnetic conditions have globally
reached moderate storm levels with NOAA Kp = 6 between 18:00 and 21:00 UTC on May 04.
The local geomagnetic conditions over Belgium have registered up to minor storm
levels. Further minor and moderate storms might be expected in the upcoming hours.
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# Solar Influences Data analysis Center - RWC Belgium                #
# Royal Observatory of Belgium                                       #
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