A case study in pressure gradient dynamics, storm structure, and the limits of a single number — tracking Maryland’s late-September coastal flood event, and the Nor’easter that followed. Weather stories rarely announce their own scope in advance. What began as a routine Cold Air Damming setup in mid-September — a strong Quebec high squeezed against a modest coastal low — turned out to be the opening act of a much longer narrative: a week-plus sequence that would eventually produce sustained coastal flooding, Gale Warnings, a genuinely deepening Nor’easter, and, in its final act, measurable evidence of partial subtropical transition.