The latest NAM data has become available.  There appears to be significant changes in the forecast. (Although consistent with several  aspects of past NAM runs.)

The latest QPF values have increased to over 2.0 inches water, BUT temperatures in both the upper and  lower atmosphere now appear to be too warm to support snow for much of the height of the storm.

It now appears that snow will begin shortly, but a change to sleet and freezing rain and just plain rain in Philadelphia and the immediate NW suburbs will occur. The change will occur before daybreak and it’s likely that it will be all mixed precipitation, mostly sleet and rain for much of the morning before changing back to snow before ending.

With atmospheric thickness levels as high as predicted by the NAM, and warmer temperatures at the surface, total snowfall may be as little as 4-5 inches in the immediate PHL area and surrounding NW suburbs within 10 miles of the city

I know I’m bucking the hype of the tv forecasts, but this is my call. I think this will be a big rain/sleet storm, not a blizzard in PHL

[stbpro id=”alert” caption=”Major Change in the Forecast”]Much of the expected snow will likely fall as sleet and rain in Philadelphia and immediate surrounding suburbs up to 10 miles from the city.   Snowfall totals may be only 4-5 inches.[/stbpro]