Why weather is so tricky for Washington DC

 well  weather i s tricky for the mid atlantic area because there are so many factors and as we meteorologists say sometimes when it comes to winter storms their is a high bust potental thats why in most cases the National Weather Service in sterling VA has been so lazy to issue winter storm watches and or warnings for snow storms and ice storms because things could change here in the mid atlantic area  the  Atmospheric dynamic  and there is a varying span of elevations between the bay and shore and the mountains  anywhere from Sea Level to 4000 ft in the mountains so  Washington proper and points at lower elevations  could see rain and some mixing in times of winter storms and points north and west of The city could see cold air and more wintery precipitation a good example of this was around the time of the vernal equinox last year  we got 4.5 inches of heavy wet snow and Washington DC had spring rain storm that was purely driven by elevations above sea level and anywhere north and west of the cities of washington dc and baltimore  got rain
We also have the I-95 Fall line  where the warm air advances to and the cold air north and west of there damns agenst the mountains. the "FALL LINE" just means thats where the Rain/Snow  battle line sets up and doesnt advance any farther than that north and west  that keeps all the northern suburbs for montgomery county north and west  in the colder air and more snow or sleet or feezing rain.  while points south and east around the tidal potomac and  Pax River NAS get all rain or a mix of rain and sleet  Montgomery county gets snow and or sleet and snow mixed or snow sleet and freezing rain  but sometimes it gets a cold rain too but thats if the rain snow line pushes farther west and north than the I-95 line .