As others have said several times, namely @WxUSAF, do not look at OP models past D10. This is especially true with potentially volatile pattern changes.
About 5:45 pm. It's PEPCO turf, but the line service some BGE territory in Howard and Baltimore Counties. It's entirely possible the flickering was the smart grid technology struggling to adjust to power demands so rapidly.
Yes. There's nothing worse than seeing zonal flow and Pacific puke for weeks on end as we enter December and you realize in the back of your head "well, there's always next year".