FAST WARNING 'PRESTO' MESSAGE  from the SIDC (RWC-Belgium) 2014 Apr 19
13:30:30

Ten sunspot groups were reported by NOAA today. Two of them (NOAA ARs 2036
and 2037) have beta-gamma configuration of the photospheric magnetic field
(although the NOAA AR 2037 is strongly decaying), and NOAA AR 2035 has
beta-gamma-delta. Since yesterday's M-flare, only weak C-class flares were
detected, the strongest one being the C2.1 flare peaking at 03:26 UT today
in a tiny sunspot group at S19E66 that seems to start emerging. A number of
C-class flares was also observed in the sunspot group that just appeared
from behind the south-east solar limb (returning NOAA AR 2021). We expect
further flaring activity on the C-level, with a good chance for another
M-class event. The proton event produced by the halo CME of April 18 is
still going on.
The solar wind speed is currently around 500 km/s and
the interplanetary magnetic field magnitude is around 7-8 nT. The
north-south IMF component Bz fluctuates between positive and negative
values, so the geomagnetic situation remains mostly quiet, with only
occasional intervals of K = 4 reported by Dourbes, IZMIRAN and NOAA. The
geomagnetic conditions will probably be quiet to unsettled until April 21,
when we expect the arrival of the ICME (or the shock driven by it)
corresponding to the halo CME observed on April 18. A geomagnetic storm
(with K index probably up to 6) may result.