  We propose to apply the weighted horizontal magnetic gradient ($WG_{M}$),
introduced in Korsos et al (2015), for analysing the pre-flare and pre-CME
behaviour and evolution of Active Regions (ARs) using the SDO/HMI-Debrecen Data
catalogue. To demonstrate the power of investigative capabilities of the $WG_M$
method, in terms of flare and CME eruptions, we studied two typical ARs,
namely, AR 12158 and AR 12192. The choice of ARs represent canonical cases. AR
12158 produced an X1.6 flare with fast "halo" CME ($v_{linear}$=1267 $km
s^{-1}$) while in AR 12192 there occurred a range of powerful X-class
eruptions, i.e. X1.1, X1.6, X3.1, X1.0, X2.0 and X2.0-class energetic flares,
interestingly, none with an accompanying CME. The value itself and temporal
variation of $WG_{M}$ is found to possess potentially important diagnostic
information about the intensity of the expected flare class. Furthermore, we
have also estimated the flare onset time from the relationship of duration of
converging and diverging motions of the area-weighted barycenters of two
subgroups of opposite magnetic polarities. This test turns out not only to
provide information about the intensity of the expected flare-class and the
flare onset time but may also indicate whether a flare will occur with/without
fast CME.
  We have also found that, in the case when the negative polarity barycenter
has moved around and the positive one "remained" at the same coordinates
preceding eruption, the flare occurred with fast "halo" CME.
  Otherwise, when both the negative and the positive polarity barycenters have
moved around, the AR produced flares without CME. If these properties found for
the movement of the barycenters are generic pre-cursors of CME eruption (or
lack of it), identifying them may serve as an excellent pre-condition for
refining the forecast of the lift-off of CMEs.
