The GFS model data is becoming available. The GFS has about 2 or so inches of snow by daybreak Thursday. But only an additional 2 or so inches during the morning hours.

The total GFS QPF is only 0.32 inches water, very consistent with earlier runs and the National Blend of Models.

With such differences between the NAM and GFS, the best guess usually is arrived at by averaging the two. With a high snow water ratio, I’ll have to revise the prediction to 4-7 inches, with 5 most likely in the immediate PHL area. Areas west will see less, areas east much more.

I guess we’ll see tomorrow!

11:30pm Update  The National Blend of Models has a QPF of only 0.28 for PHL and really drops down to 0.20 for Blue Bell.  This sort of edge condition with such a rapid taper is going to take a bite out the snow fall prediction accuracy. The 4-7 is looking too high. 4-5 is more likely for the immediate PHL area.