To my post above, one thing I believe may have happened here was the circulation was much more mature and deeper than forecasters had expected. A storm that had been forecast to degenerate into a trough in the Carolina’s largely kept its surface circulation intact into the mid Atlantic. This led to a much stronger southerly and easterly flow which enhanced moisture transport and efficiency longer than expected so the “core” was able to sustain itself longer than expected. I think when you see weak storms hit land a lot of times they kind of vanish inland and just their moisture is left but when they become more vertically stacked and mature it takes them longer to wind down and you can see a core of heavy rain sustain itself longer. That’s my 0.02 as to why Chantal was so much worse than forecast this weekend