RAP is overdoing the rates, it wants a 3"/hr deathband in DC with the TROWAL. I don't think I've ever seen 3"/hr with a TROWAL on a rapidly exiting system.
If this was just colder with some CAD to start, this would have been beautiful with the "new" track. 700mb low slides right over top of us with the 850mb low just over southern MD. *chef's kiss*
Also the northern stream s/w is a bit faster than expected 48 hrs ago (this is also what's bringing in the cold air aloft), and perhaps a tad stronger.
No, it's the timing of how the southern stream cut off low ejects, it's been getting slower / further west. Allowing the northern stream s/w over SK/MB/ND to kick it further south.