Storm System to Bring Major Snowfall Accumulations to Much of southern New England Wednesday, February 5th, 2014

The active start to February continues on Wednesday as yet another storm system is expected to impact southern New England.  This system is forecasted to be a bit stronger than what we just dealt with as the system will have a bit more organized structure with much stronger lift and a further northward track will mean increased moisture as well.  All these ingredients will come together to bring the potential for major (8-12'') snowfall accumulations across a chunk of the region.  We can't even rule out some areas perhaps picking up over a foot of snow as well.

With a storm track which is expected to be virtually just south of CT moving across the extreme outer portion of the Cape this is going to allow for some warmer air to work northward across southern CT, southern RI, and far southeast MA (including the Cape) and this will reduce snowfall totals across these parts thanks to more in the way of mixing.  We also may see some sleet mixing in as far north as the CT/MA border for a period of time.  A storm track like this as well means an increased thermal (temperature gradient) in the mid/lower levels of the atmosphere which also means stronger forcing and lift over the region:

  When looking at how much moisture is associated with this system, computer forecast models are all in agreement there will be loads and loads of moisture associated with it.  In fact, the consensus between the NAM/GFS/Euro models all have about 0.50'' to 1'' of liquid falling in a 12-hour period!  Forecast soundings also show the snowgrowth zone will be located between about 15,000-20,000ft up which is what you want to see and the soundings do show some good lift within this zone at times.

While all of these are certainly positives for a pretty sizable snow event, there are a few negatives as well which may reduce the potential for a much higher snowfall accumulations.  Computer forecast models really begin to dry out the mid-levels of the atmosphere rather quickly during the late morning into the early afternoon hours as dry air races in from the west and southwest.  This dry air is not only a precipitation shield eater but it vastly reduces snowgrowth and ratios.  There are also some signs of some subsidence zones ( caused by "negative lift") which will mean there may be some spots where virtually no snow is falling (or the intensity is extremely light) while only a few miles away it's snowing quite heavily:

Given what we are presented with right now this is what I am currently thinking for snowfall accumulations.  The highest snowfall totals will be confined across far northern sections where dry air will be less of an issue and snowfall ratios will be a bit higher.  Interior northeastern MA back to Worcester will also be another jackpot area as dry air will be less of a factor here as well and guidance suggests the best banding may pivot over this area.