Tracking Tuesday's Storm Potential

Computer forecast models have been in rather strong agreement on a potential major storm system to impact southern New England this upcoming Tuesday.  The agreement between the operational models and their ensembles have been rather impressive and this leads to a higher than average confidence in at least some sort of impact on Tuesday.  However, there are still numerous questions with regards to the details which is expected for this time frame.  Over the next few days as the details become more clear we will have a much better idea on how significant of an impact we are looking at.

What is the driver for this storm?  We are tracking two pieces of shortwave energy which computer forecast models are in strong agreement that these piece of energy will phase and the result will be explosive cyclogenesis just off the east coast:

The explosiveness of the cyclogenesis will be aided by an intensifying 500mb level jet streak of 100+ knots which develops and rounds the base of the upper trough.  This will allow for further amplification (strengthening) of the trough and enhance the rapid cyclogenesis of the surface low pressure:

Looking at each GFS computer forecast model ensemble from the 12z run of March 10th, we can see very strong consistency between each member for not only an impact from this system but the potential for rather significant impacts:

Over the next few days we will be watching several key features very closely and how the computer forecast models handle these features.  One major question as of right now is with regards to the exact track of the storm as this will vastly determine the significance of the impacts.  A storm track closer to the coast will increase the likelihood if ushering in warmer air into parts of the region which could result in reduced snowfall accumulations and risk for mixing and/or rain.  Of course there is still a shot this system goes completely out to sea, however, at this stage I think that sort of scenario is a bit unlikely.  One thing to watch for when determining how close to the coast a system will track is the behavior of the North American Oscillation over the next few days.  When the North American Oscillation transitions from a positive state (characterized by below-average 500mb height anomalies in and around Greenland) to a negative state (characterized by above-average height anomalies in and around Greenland) this yields what is called a "block" and this makes it rather difficult for a storm coming up the coast to go out to sea.  When the North Atlantic Oscillation transitions from a negative state to a positive state as a system is working up the coast this increases the likelihood the storm could scoot further off to the north and east.  Currently we have a North Atlantic Oscillation which is slightly positive and is expected to become more positive:

What this suggests is unless some other processes (such as a vast negative tilt to the system) occur this could mean a higher likelihood for a track a track which is more westerly as opposed to easterly.  This could mean mixing issues for a portion of southern New England.  

Outside of the track of the surface low, the tracks and development of the 925mb, 850mb, 700mb, and 500mb lows will be rather critical as well. Taking a look at the projected track of the 850mb low (as forecasted right now) the track is right over CT.  This sort of track would allow for warm air advection into a portion of southern New England which would lead to mixing issues:

The projected track of the 700mb low also raises some red flags.  The development and track is pretty much west and then over southern New England which is a huge signal for dry slotting:

These are some of the features we will be watching over the next few days but Tuesday certainly has potential to be quite the potent storm system which as potential to drop major snowfall accumulations.  Further updates will be posted as the situation becomes much more clear