Another light to moderate snow event is on the table going into later Thursday and Friday all thanks to a Clipper system sliding to our south. And then redeveloping off of our coastlines bringing back a inverted trough through northern Delmarva and Southern New Jersey. Enough to make for a plowable snow event for the region.
Snow could become heavy at times north of Dover once the energy begins to transfer off the coastal of New Jersey. When this happens, a potential inverted trough or “trowal” develops with a corridor of enhanced moisture pointing back towards the coast.
What is a trowal exactly? (warning it’s term heavy) A trowal is a trough of warm air aloft. Typically used during winter weather, it is a “tongue” of relatively warm/moist air aloft that wraps around to the north and west of a mature cyclone. It is best analyzed between 750-550 millibars using equivalent potential temperature (theta-e). Areas of intense lift and frontogenesis are commonly associated with TROWALs, hence they are favored regions for heavy and/or prolonged precipitation. During a winter storm, the heaviest snowfall amounts frequently occur along and north of the TROWAL axis.
This area will have the greatest shot of getting near that 5 inch mark throughout the day on Friday. Snow will move in during the predawn hours Friday and continue into the evening hours.
Still will be seen across much of the region before a big warm up trend will be arriving towards next week. Heaviest amounts of 2-5″ will be likely across Northern Maryland, Northern Delmarva, and most of Southern New Jersey. Further south will be dealing with less precipitation overall with the primary axis of moisture will be positioned just to north. Subsequently with lesser amounts over all but that can change depending on the track of this TROWAL and low placement in later outlooks.