A rather significant s/w will be slowly pushing east through ME Tuesday afternoon. Associated with this s/w will be pretty impressive jet dynamics and a cold pool aloft/steep mid-level lapse rates. Surface dewpoints will only be in the mid-to-upper 50's which will limit instability potential, however, the combination of temperatures into the lower 70's and steep mid-level lapse rates may result in 250-500 J/KG of MLCAPE. Given degree of shear/cold air aloft, scattered showers and t'storms should develop very early in the afternoon. The stronger cores will be capable of strong winds as cores collapse along with some hail...perhaps even a few large hailers.
This will be predominately ME...maybe northern NH.