Hey I agree your reasoning with Sun/Mon is sound, wouldn’t be the first time a system developed later further east/northeast.
Friday Night though synoptically has a lot going for it... strong gradient and baroclinic zone between cold north and humid/warm south. Looks like prolonged period of upper level divergence with good right-rear quad of jet streak positioning.
I guess maybe it falls apart but even the ICON has 1” up to VT/NH and 2” South Coast. 18z ECM wetter too... 1-1.50” for you.
Hard to give congrats to someone who gives no meteorological reasons other than , lol.