Big differences today between the GFS model and the NAM model. The latest NAM cranks out 3-5 inches of snow for PHL.
The GFS has cranked out much less snow in the afternoon run, just a coating.
UPDATE: tonight’s GFS has 1-2 inches of snow for PHL.
This clipper could surprise in either direction, most likely in the lower accumulation range. Both models start the snow after 1PM and taper to flurries about 7 PM.
The models are coming together in predicting the development of a coastal storm that will be a slow mover, affecting us directly from Monday night into Wednesday morning, then indirectly into Thursday.
The models have become somewhat consistent in predicting very heavy rain for our area on Tuesday. The NAM has almost 2.5 inches of rain falling! Temperatures appear too warm for snow to form during much of the storm, but it looks like a possibility that wrap around cold air and moisture will bring us some wet snow, especially in the NW suburbs Tuesday night into early Wednesday morning.
Temperatures at the surface will be just about or above freezing, so accumulations will be limited. But this wrap-around moisture will be occurring at nightime Tuesday, perhaps allowing 2, maybe 3, wet inches to accumulate on grassy surfaces by Wednesday morning.
So, no accumulations on Tuesday, just heavy rain and windy, then possibly 2 inches or so wet accumulation later Tuesday evening into Wednesday morning.
Not much cold air around after this storm and a significant warm up may occur next week.