So the coastal part of the storm is starting to separate from the bands over the western part of the forum. My guess this is where the norlun may set up initially and then migrate east towards DC, and then wherever it migrates to, it will jus sit for a few hours with 1-2”/hr rates. Whether it gets stuck over fdk-moco-loudoun, or moves all the way to over DC like the HRRR shows remains to be seen.
FWIW, winds are still blowing from the NNE at my place, so it may start forming to the west of me