Some observations for 98L's tropical prospects - as many have noted, SSTs are anomalously warm along the Mid Atlantic coast, and given ongoing convection off the SC coast, it's possible a new circulation may develop farther offshore, keeping 98L's eventual track over water.

Another factor influencing 98L's track is its short term evolution (GFS faster vs. ECM & UKM slower), and amplitude of upstream trough (GFS deeper, latter weaker). GFS scenario has quick N track inland, latter leads to slow & farther east track over water increasing % of TC/STC.

Model cyclone phase space diagrams differ based on track & timing. UKMET's offshore scenario, coupled with anomalous ridge poleward of 98L, leads to a warm core through ~DE's latitude, and only transitions to cold core between Cape Cod & Maine.

The last time a TC maintained tropical characteristics this close to the Northeast US coastline was Hurricane Irene in 2011.

(Caveats: Sandy in 2012 became extratropical just before landfall, Andrea in 2013 had impacts as an EC, and Arthur in 2014 skirted just past the region.)