Update: GFS improves slightly, gives Boston a nice hit now. Expect the model to become more aggressive especially if Euro holds course at 1:00PM.
The threat for a nice system with some wintry potential will be on the 23-24th. An unusual set up from most storms this winter as we will be dealing with a very slow moving area of low pressure, but the usual part about it is we wait on the cold air!
On the latest European model Philly is rain to snow, and by eyeballing it from the plots above I would say a 4-7" snowfall.. NYC-BOS is the jackpot 6-12".
The important thing here is the European model is picking up on this winter storm threat, and the other models will catch on. The Canadian model came around last night showing a nice snowstorm from NYC-BOS. The models are having trouble with the blocking signature from the Great Lakes region into the Hudson Bay. We talked about this before, a rex blocking signature is one that models love to breakdown too quickly. And we are seeing models play catch up here to the idea that this system will not get the boot eastward like the GFS shows. And to some extent probably not as quick as models show now on Euro and CMC.
Above is the upper air pattern at hr 102, we can see the ridge building into the Hudson Bay over top of the vortex in Minnesota. This blocking configuration will allow this vortex to stay put as our main system moves around it. As our main s/w moves around the vortex it will develop a coastal low (as seen in above images with precip) and slowly push northward before getting a boot east.
During the time of the storm system we see the confluence building allowing for high pressure to be situated in Eastern Canada helping to usher in some colder air as the storm intensifies. After this frame the model breaks down the blocking signature and sends the vortex eastward fairly quickly preventing a much bigger storm from impacting New England. Could also lead to Philly getting cut off from the snow slightly quicker.
The problem with the rapid movement east of the vortex is that it really does not make much sense. Then we factor in the model issues with handling rex blocking signatures and it makes sense that the models are trying to push this east too quickly. As the Euro alludes to above this would allow colder air to come in and change rain to snow.
The models are increasing the threat for a winter storm on the 23-24th for the Northeast, but right now it looks like the best chance of this verifying will be from NYC-BOS, but we will see where models take us today and tomorrow!
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Great as always MIke. Not surprised NYC-BOS is in the mix as it looks like we'll be coming off an east bias NAO.
The changeover solution for Philly/EPA is always difficult to determine.
Still not overly excited about this one, but I think it will take more data for models to get a good hand on it. I also REALLY like how this is the first of several potentials over the next couple of weeks. Signals look much more favorable next week. Looks like it's going to get interesting in the end here - go figure.