For starters the model is now seeing the signs in the E PAC with pumping up the northern stream ridge. This allows more amplification and a stronger deeper trough that forces a low to develop closer to the coast. Still not where we want it but it is the trends...
The ridge is weaker in northern stream and does not show much precip make it north of NC/S VA. This was the 12z run today of the NAM.
NEW NAM does something we have been waiting to see from this model and that is a stronger ridge. This leads to a stronger and deeper trough with significant precip making its way northward.
The coastal develops much sooner and throws back some nice qpf for DE into VA but still too late for others to benefit. The key here is the west shift compared to the 12z run that is below for the same time frame:
In the frame above the Jersey shore went from nothing to a trace to 2" in a model that changed that much in 6hrs. With data still coming in from the PAC for tonight's runs it seems reasonable to expect this trend to continue.
The 18z GFS ends the trend by missing the northern stream apmlification, other than that it still hits the area with a light snow event. But if it amps up in tonights runs we will see a better result.
Reggie, you mentioned that the low is forecast to be very close but just out of reach for the Delaware Valley to see significant snow; bear in mind that this low was forecast to be far, far away not too long ago. Keep the faith, the 00Z will be important.
As most of us know, the 18Z is an off run. It is likely that the current forecast for southeast PA is lower then what we'll see. Looking at the northern system, the water vapor and the southern stream, along with the trend continuing for higher qpf with ratios of 20 to 30 to 1should make snow lovers happy.
The 6Z/18Z is notorious for showing solutions that are biased to the SE. I expect the 00Z suite to shift about 75-100 miles to the NW with potentially significant snows along and east of 295 and the NJ turnpike. Philly will probably be in the 2- 3" range while people along and east of the demarcation boundary mentioned should see 3-4" with some shore folks picking up 5".
18z GFS is in and it continues the trend of the 12z run and pushes the storm further North. That is one part of the equation. Now all we need is for it to develop faster, and we will be in a moderate snowstorm. ! Can we make it happen? Tonight's full 0z model guidance will be interesting
the way I look at it is yes the trends are slowly coming back in our favor but BIG DEAL, the trends are not significant enough to give us a major winter storm. So now it looks like we will get an inch of snow instead of flurries. -__- Who the heck cares. The low will develop tantelizingly close to the coast but not ENOUGH to give us snow. The clipper tonight, ruins the friday storm. Sry folks, but enjoy your inch.