We currently have a storm system over the Ohio Valley in the process of transferring to the coast, and will form a coastal low with wintry precipitation but to be honest I can’t say im even remotley close to being impressed with what im seeing here
The precipitation tonight is expected to be mainly virga, with just light snow/mix developing very late tonight over southeast PA/Philadelphia area and southern NJ
We have to remember we are now in early spring, and clearly the air mass in place is not very cold as the area range from temperatures in the upper 30s to mid 40s
Now there’s no doubt that tomorrow afternoon we will have a strong coastal low off the New Jersey coast, and there will be snow flying in the air for many, and even some moderate to heavy snow, mainly to the south of New York City , BUT surface temperatures throughout the area are expected to be above freezing throughout the storm, that combined with timing during the day with the strong sun this time of year and the result is snow or mix falling all day but not much to show for it when all said and done tomorrow night.
The main trigger needed for accumulating snowfall would be very heavy snow rates capable of overcoming the strong March sun , as the air mass in place is far from cold enough, with lack of high pressure to the north and a east-notheast flow developing tonight
The main impact in my eyes looks to be wind along the immediate coast and some coastal flooding/beach erosion
Also with the strong block to the north and a storm that is forced to move due east off of NJ rather than move northeast, there will be a sharp cutoff in precipitation on the north side which appears to set up around the New York City area so in areas where it would be cold enough to accumulate in the higher elevations of NW NJ an NE PA , the precipatation will likely not make it that far north
With this said here are the amounts I expect
NE PA through Connecticut Flurries/snow showers with little accumulation
NW NJ/New York City/NE NJ/LI- Periods of Light Snow/mix – Coating-2 inches on grassy surfaces , wet roads
Southeast NJ (Belmar -Cape May) Periods of moderate to heavy rain/snow mix – C-2 inches snow accumulation, up to 1 inch of liquid
Allentown PA/Lehigh Valley – 1-3 inches wet snow, wet roads
Philadelphia/western suburbs to Central NJ – Periods of moderate to heavy snow/mix – 2-4 inches on grassy surfaces wet/slushy roads outside of city
Lancaster PA- Periods of moderate to heavy snow 3-5 inches
So clearly im not expecting a very impressive wintry side to this, there will be snow and wintry preipatation falling for most of the area and the best chance for accumulations will be where the heaviest precipitation is and away from the immediate coast, as heavy precipitation would help to cool the atmosphere and overcome te March sun, which puts us over southeastern PA , which is the only place where appreciable accumulation seems possible in my opinion (in my forecast area) , this storm will have to be nowcasted as March snows are always tricky though.
So just a quick overview , light precipatation late tonight spreads slowly from south to north, overspreading southern NJ to Philadephia and southeast and Central PA , this slowly spreads north to the New York City metropolatan area, in the afternoon as the coastal low gets going moderate to heavy precipatation expands and impacts Philadephia metro, southern NJ ,southeast PA and the Delmarva, some moderate precipatation may clip the southern suburbs of the New York City with overall minor to moderate snow accumulation throughout the area, least along the coast and the northern interior, most around and especially west-southwest of Philadelphia to the western suburbs of Washington DC .
After this we enter a calm period of weather with temperatures slowly moderating from well below average to near average by Easter Weekend, with temperatures in the 50s by day and 30s by night mid to late week and into the weekend!!