  There is a wide range of eruptions in the solar atmosphere which contribute
to space weather, including the major explosions of radiation known as flares.
To examine pre-event behavior in delta-spot regions, we use here a method based
on the weighted horizontal gradient of magnetic field (WG_M), defined between
opposite polarity umbrae at the polarity inversion line of active regions (ARs)
as measured using from the Debrecen Heliophysical Observatory catalogues. In
this work, we extend the previous analysis of high-energy flares to include
both medium (M) and low-energy (C and B) flares. First, we found a logarithmic
relationship between the log value of highest flare class intensity (from B- to
X-class) in a $\delta$-spot AR and the maximum value of WG_M of the 127 ARs
investigated. We confirm a trend in the convergence-divergence phase of the
barycenters of opposite polarities in the vicinity of the polarity inversion
line. The extended sample (i) affirms the linear connection between the
durations of the convergence-divergence phases of barycenters of opposite
polarities in delta-spot regions up to flare occurrence and (ii) provides a
geometric constraint for the location of flare emission around the polarity
inversion line. The method provides a tool to possibly estimate the likelihood
of a subsequent flare of the same or larger energy.
