We all know that predicted snow totals are very imprecise until about 12 hours before the snow starts. So the data from tonight’s model runs should be taken as preliminary.
Here are the current and latest NAM and GFS model QPF values for what is starting to look like a true snowfall for Saturday. The GFS has over 0.40 inches water and the NAM has about 0.30 inches water falling as snow for PHL. That translates into 3-5 inches of snow, starting about daybreak and ending early evening . Areas in NJ may have significantly more, areas west less.
The stastical models have declined in precipitation probability, but the latest isn’t available.
A developing situation. Stay tuned.
Only a day after posting that the deterministic GFS and NAM models have the snow well to our east missing us, today’s models GFS and NAM have jumped onto the snow bandwagon with the statistical models with the light snow occurring before daybreak on Saturday and continuing during the daytime hours. Currently the NAM is showing 2-3 inches in PHL!
The statistical models have been consistently predicting light snow in NJ and extreme SE Pennsylvania for several days. Interestingly, the statistical models have reduce the probability just as the GFS and NAM show increased amounts of snow.
It now appears that the coastal low pressure system will intensify enough to throw snow back into our area through the day Saturday; the snow will be light in PHL with somewhat heavier accumulations in NJ. The NAM now shows 2-3 inches in PHL. The GFS shows 3-4 inches with heavier amounts in NJ! I expect the predicted amounts to change by Saturday.
The GFS and NAM have continued their forecast of having the low pressure system move east of the coastline and having the snow miss us. The statistical models now show reduced chances of it changing paths.
So cancel that light snow for Friday into Saturday. There’s still a chance of flurries on Saturday. So the GFS and especially the NAM seemed to have done better than the statistical models with their storm track this time around. I’ll update Friday evening.