11 am NHC Discussion mentions baro enhancement keeping the storm from weakening too fast, even though the track actually shifted a tad west and is now basically entirely inland after landfall
Current westerly vertical wind shear of 20-25 kt is expected to
decrease somewhat during the next 12 h and also become more
southwesterly, which will be in better alignment with Isaias'
forward motion vector. The decrease in the shear should result in
less tilt to the cyclone, allowing Isaias to strengthen and regain
hurricane status just before making landfall, and most of the
intensity guidance shows a 60-65 kt system at that time. After
landfall, Isaias is forecast to only slowly weaken due to
interaction with an unusually strong winter-type jetstream that will
be possessing winds of 100-120 kt. Expected strong baroclinic
forcing will keep Isaias' circulation intact and also produce very
strong wind gusts along the Mid-Atlantic states tomorrow. As a
result, the gust factors at 24-48 h have been increased above the
standard 20 percent in the Forecast/Advisory (TCMAT4). The cyclone
is forecast to be absorbed by a larger extratropical low over Canada
in 3-4 days.