I'd suspect that lack of confluence is limiting initial precip expansion given no dual jet structure until it's in New England.
As you said it's a Miller B. Basically we have stale air and await favorable timing of cold front and transfer to our S just in time for the coastal to form and column to be sufficiently cool.
Mids are essentially right over us, another risk with late blooming miller b.
Yes, way too much detail, but it's a look that's been present past few runs.
Doable, just extra special fortunate should it work out.