That looks like an overrunning thing like the op showed. In reality it's probably more of a boundary that separates cold air and warm air very close by. Might be oranges at H5, but srfc temps would be colder. Now where is that boundary? Your guess is a good as mine.
This look is different because eastern Canada is cold and not torched like the previous -PNAs. Also, those were modeled to dig, while at least as of now...this doesn't dig as deeply and it serviceable.
Caveats apply, but it would work.