I was wondering about that too, and it seemed to be more NW/SE oriented. Probably a combination of a normal temperature gradient and a bit of cloudiness over northern VA.
Mesoscale models have a light band of precip coming through in the morning. Surface is residually cold, but the column is a little too warm. So, more of a mix. If it is delayed at all the surface will warm and it'll just be cold rain on the 24th.
I don't see any guidance that is this cold, but sure enough it is in the AFD too:
Sunday night brings
lows in the single digits to lower teens for most.
They still had the old wind chill scale back then and the numbers were insane back home in Minnesota. -60, -70, -80. We were out of school for a few days and I remember just sitting and watching tv coverage of the Northridge earthquake.