My Final Call: Issued 6:00 PM Monday !
Much of this event will be caused from Upper Level energy and CAA (Cold Air Advection) which will induce instability and more convective type precipitation. During the beginning of the event, most precipitation will be showery and periodic in nature. But as the strung out energy reaches the coast on Tuesday, a weak area of low pressure will develop near and just off the M/A Coast, near VA or the Delmarva coast.
This will help enhance snow on Tuesday and into Tuesday night, mainly between Baltimore/DCA and points northeast into The Delaware Valley, so the higher snowfall amounts are likely there.
These types of systems and setups are tricky to forecast and the Norlun trough may come into play. This is an Inverted trough and becomes stretched out energy, that sets up over a meso scale region. This can cause moderate to heavier bands of snow to develop from the Low and points Northwest.
For much of Southern and Central VA this will be a very minor / Non event !
Showers changing to snow showers and flurries Tonight into Tuesday.
ROA / LYH / CHO and RIC, VA will see no more than a Coating to maybe a few spots seeing 1", especially towards the CHO VA Areas !
For DCA and Northern VA 2"-4" !
BWI / Central and NE MD: 4"-8"
For The Delaware Valley Region:
The Main event occurs later tonight into Tuesday Evening ! Best chance for Moderate to Heavy snow occurs Later Tuesday Morning into the early Tuesday evening hours ! Snow tapers off and ends after Midnight.
For PHL / SE PA / Southern and Central NJ, and Northern DE:
A general 3"-6" can be expected with a few spots seeing 7" or 8".