INFO FROM SIDC - RWC BELGIUM 2018 Apr 20 12:30UTC

The sunspot group which appeared from the behind of the East solar limb
yesterday got numbered as Catania sunspot group 78 (NOAA AR 2706). This
sunspot group was source of the all (low B-class), flaring activity during
last 24 hours. We expect that Catania sunspot group 78 might be the source
of the B-class flares and possibly also isolated C-class flare in the
following 24 hours.
There were no Earth directed CMEs observed since the last report and the
solar protons remain at the background level.

The in situ observations showed sudden increase of the interplanetary
magnetic field magnitude (IMF), solar wind speed, density and temperature
at about 23:19 UT yesterday evening. All this indicates arrival of the
shock wave, however presently it is still unclear if the shock wave will be
followed by the ICME or this is a shock in the solar wind related with the
expected arrival of the fast flow. 
The shock wave was followed by gradual increase of the solar wind speed and
IMF. The fast solar wind (up to 515 km/s) and longer intervals of negative
values of the Bz component of the IMF (down to -19 nT), resulted in the
active to storm geomagnetic conditions reported this morning (local station
at Dourbes reported K=5 and NOAA reported Kp=6).
The solar wind speed is presently about 480 km/s and the IMF is about 14
nT. If the solar wind speed will continue to increase and the Bz component
will show longer intervals with negative values we can expect continuation
of the disturbed geomagnetic conditions in the coming hours.