Mon 11:40 AM Update: This morning’s other models (WRF-NMM, WRF-ARW and the GFS) all show barely a coating to a fraction of an inch of snow accumulating by the end of this storm around midnight in the immediate PHL area and adjacent counties.  The HIREF shows a stronger snow shower possible about 6 PM, not substantially adding to the total.

As I mentioned last night, the new GFS probably did the best with this storm overall.   The much-touted European ECMWF seems to have over-forecast the snowfall here.  

…from earlier this morning—

I was able to review the latest NAM, NAM-NEST and RAP.  All are consistent with the coating to an inch for Philadelphia and surrounding counties.   Below is the NAM snow depth forecast for late this evening—

NAM Snow Depth forecast (in inches) for midnight Monday.  (click for larger image) Most areas much less than an inch around here.

I don’t anticipate any more changes.


Added Snow Total Forecast Graphics:

GFS Snow Depth
NAM Snow Depth Forecast
ECMWF Snow Depth

Yes, it’s snowing out and that was expected. The forecast question I’ve been trying to address— what level accumulating snow can we expect by the end of this storm?

Last night’s 1 AM run of the models continue with the forecast of a coating to an inch of snow accumulation for our area.  That’s true of the NAM, GFS and high resolution Canadian.  The most recent hourly HRRR  (High Resolution Rapid Refresh) also maintains a low accumulation by the end of the storm this evening.

The only exception is the ECMWF, which has changed from its last run, but still gives us 2 inches with a rapid gradient increase to our north.

It sure looks like snow will accumulate and the intensity is much more than the NAM or GFS forecast QPF values.

Let’s see how it plays out.  Could all these models be wrong??  Could the Eagles lose to Miami??    Stay tuned.

The next models become available later this morning (NAM about 9:30 and the GFS about 10:38 AM) I’ll update if I can.