Latest NAM model has rolled out.  Extraordinary amounts of QPF ( 2.34  inches water)  falling as snow.  The NAM has been remarkably consistent with these high amounts and I’m thinking that at least 24 inches of snow and likely 25-30 inches will be final amounts.  

I know I’m well above the official forecast snow totals, but as I said on my earlier post today, the NWS tends to ignore the NAM model for snow amounts, preferring the various global models like the GFS and the ECMWF.    In the past decade, when they’ve underestimated snow totals, it’s seems like they have always  ignored the NAM model.  (Similarly, last year’s fizzled “blizzard”, where they were predicting a monster storm this same week in January,  was correctly modeled by the NAM and incorrectly by the GFS and European models. )

So despite the tendency for the NAM to run a bit high in QPF, I’m sticking with the extraordinary QPF of the NAM for this storm.

Other changes suggest a little heavier and early start for the snow tonight.  So while things were looking closer to a 10 PM start, the HRRR (based on the NAM model) shows snow starting in Philadephia as early as 7-8 PM.

Sustained winds, around noon tomorrow, may be as high as 32 mph with higher gusts.  We likely will be close or reach the true definition of blizzard conditions.