The weak line segment progressing across S NE did indeed seem to lead to new development (upon its leading outflow boundary) as it reached an axis of better surface-based instability to its east, as analyzed by the 3-km LAPS. Another example of the good visualization / analysis tool of reflectivity + LAPS CAPE.
21Z LAPS analysis of 2130Z SBCAPE + Reflectivity Mosaic (region of approx 1500 J/kg CAPE is scalloped)
21Z LAPS analysis of 2215Z SBCAPE + Reflectivity Mosaic
Picca