A nice little "pre-game" before severe weather season kicks in but looks like we'll see a low topped squall line move across much of southern New England late Wednesday afternoon and early evening. While the greatest threat for damaging wind gusts likely exists to our west (across NY and northern PA) the potential will exist for much of the region for localized embedded damaging wind gusts and perhaps even some small hail.
Instability is not the driver in this event as instability will be quite marginal with temperatures only into the 60's and dewpoints in the 40's to 50's, however, the presence of steep mid-level lapse rates aloft results in modest instability (500 - 750 J/KG of MLCAPE). The driver here is strong forcing from the approaching cold front and very strong jet dynamics characterized by 50-60+ knots at 500mb and 35-40+ knots at 850mb. Fairly steep low-level lapse rates, low-level dry air, and strong LLJ will also favor embedded damaging wind gusts, likely on the leading edge of the line. With steep mid-level lapse rates and cold air aloft, small hail is also possible.