I'm sure you've heard the expression, 'dry begets dry' I've read years ago that aridification of land can 'suck' moisture out of the atmosphere - not as efficient as evaporation of moisture out of soils but it does go the other direction. We can sort of hint of that happening here, with DPs struggling to get to 65 N of the Mass Pike, despite hours after hours of stream-lined flow from an upper 60s source.
Hi resolution sat loop shows scouring shadows N-S in the Hudson Valley ... we could be witnessing a feedback where marginal theta-e injection is not sufficient to offset the absorption - just wondering...
But the whole axis of instability and triggering and all that is too far west, either way... Without DP issue, this looks like that typical scenario where late evening what's left comes through for us eastern folks as anvil exhaust light .. moderate rain for 25 minutes and a distant boom.