Quick Moving Storm To Bring Accumulating Snows To Much of Southern New England on Tuesday

The active weather pattern continues across southern New England as we are dealing with yet another storm which is set to impact the region during the late morning on Tuesday and lasting into the late evening hours.  While this storm does not look to be as major as significant as the past few systems we've had, this system does look to drop for plowable snows across the region.  The timing of this system will also coincide with morning rush hour traffic, afternoon rush hour traffic, and evening rush hour traffic and with this the largest impacts from this system will be on travel and commute.  

Our driver for the system tomorrow is currently this very strong piece of energy at 500mb (~18,000ft AGL) which is currently located out in the Ohio Valley region.  This very potent piece of energy is associated with a weak area of surface low pressure and while the surface low may be weak, the strength of the energy is really driving this system.  In fact, portions of  IL/IA/MO have had some pretty impressive snowfall rates along with thundersnow!  This energy is quickly moving through the fast moving mid-level jet stream and will be approaching our region tomorrow morning:

As stated above, this potent piece of energy is associated with an area of surface low pressure and this surface low will track through New England tomorrow and as it does so we will begin to see snow break out.  Also, as the surface low moves off the coast, it is actually expected to strengthen some.  This will lead to a jackpot of higher totals across portions of interior northeastern MA, southeastern NH extending into coastal sections of ME:

While this is expected to be a quick hitting system with precipitation lasting anywhere between 6 to at most 10 hours, there will be some pretty intense lift associated with the system.  What this will do is 1) lead to pretty intense precipitation (snowfall) rates and 2) For areas that may be a touch warm as far as surface temperatures go, this will help to offset that.  Unfortunately for areas on the outer Cape, the degree of warmth towards the surface may yield to a changeover to rain:

With such intense lift around, we could be looking at snowfall rates approaching 2'' per hour and perhaps even as high as 2.5'' per hour at times tomorrow during peak intensity.  While peak intensity may only be a few hours, this means snow will pile quickly.

Given what we looked at above, we are probably looking at two areas of higher snowfall amounts.  One area being in the NW Hills of CT extending into the Berkshires and another area being the NE Hills of CT, the Worcester Hills, and interior NE MA into portions of NH and into coastal ME.

As stated above, the major impacts from this system will be the impacts on travel as some of the heaviest snowfall rates will be occurring during times of higher traffic activity, especially across eastern MA.  Further west into CT the snow should have slowed down by 4-5 PM so at this point in time the highest travel impacts will be occurring out across eastern MA and back into portions of RI.

Below is what I'm currently expecting in terms of snowfall accumulations:

Strong Coastal Storm To Bring More Accumulating Snowfall To Southern New England Along With Blizzard Conditions to Eastern Southern New England

Days after a rather intense coastal storm dumped major snowfall accumulations across a large chunk of southern New England another system is set to impact the region Saturday night and bring another round of snowfall accumulations and unlike this past storm, we will be dealing with an all snow event.

Our main area is focus is this piece of energy which is digging into the southeast.  As this energy continues to dig into the southeast, the associated trough will continue to dig and this will lead to further intensification of the energy.  The energy will then work off the Carolina coast, and while doing so, it will draw in moisture from the Atlantic.  The system will then continue working northeast, off the US coast where the system is expected to undergo rapid cyclogenesis (strengthening).  The system is expected to track far enough off the coast to support a cold enough thermal profile for all snow but track close enough to allow for heavy precipitation to wrap around into southern New England:

Over the past day or so, computer forecast guidance has really gone...wild with this system just off the coast.  In fact, we are looking at yet another major (widespread 8-12'') to significant (12''+) snowstorm across the region with the highest snowfall totals perhaps confined to eastern MA, including the Cape.

The westward extent of the highest snowfall totals is all going to depend on the exact track.  Right now there is some disagreement as to the exact track of the storm and that does make for some shaky confidence with regards to how far west the heaviest snow will track.

Besides a several hour period of moderate to heavy snowfall winds will also be of concern, especially across eastern MA where blizzard conditions are likely as winds will be sustained 25-35 mph at times with gusts perhaps as high as 60 mph.  The exact track of the storm will also determine how far west we see these strong winds occur...something else to keep in mind.

Computer forecast models also briefly work in a pocket of instability in the mid-levels of the atmosphere.  This instability pocket riding overhead, coupled with very intense lift from the system could lead to some embedded pockets of convection leading to thundersnow.

Snow is expected to break out across western portions of southern New England as early as 3-4 PM and this could actually happen as early as 2 PM.  Once the snow begins, it will rapidly increase in intensity and the height of the heaviest snowfall is expected to occur between about 5 PM and 1 AM (lasting until 3-4 PM for eastern sections of southern New England).

Below is what to currently expect as far as snowfall totals are concerned:

Major to Significant Winter Storm To Impact southern New England Thursday into early Friday

Over the past few days confidence has vastly increased that a storm system developing across the southeastern United States will work up and track close enough to the coast to impact southern New England.  With several sets of computer forecast guidance suggesting a rather strong system, these impacts will be rather significant as portions of the region will see major (8-12'') to significant (12''+) snowfall accumulations.  Given the expected track of the system, we will also have to contend with plain rain, sleet, and perhaps some freezing rain.  This system will also be accompanied by some strong winds as well.

While confidence is extremely high of a storm track close enough to the coast to impact the entire region, there is still a great deal of uncertainty with regards to the exact track of this storm system.  This is ultimately going to be absolutely huge when it comes to determining who remains all snow, who mixes or changes to rain, and where the axis of the highest snowfall totals will occur.  Unlike some of the past storms we have had this winter, we don't have a high pressure system to our north to keep colder air locked in place across the region and with the models strengthening this system very rapidly off the Carolina coast, this will allow for warmer air to try and work into portions of southern New England.  A track difference west/east of as little as 30-50 miles will be the difference between something like 3-6'' of snow and potentially as much as 12''!

What we also have to watch is the track of the 700mb low.  This is extremely important for two different reasons.  1) The highest snowfall totals along with the heaviest banding of snowfall occurs just to the northwest of the low pressure track.  This is where lift is typically the strongest along with very strong forcing.  2) Areas virtually in the direct path of the low track and just south and east typically end up being in the dry slot.  This is where drier air from aloft descends downward or when drier air gets wrapped into the system.  The drier air eats at the precipitation and the moisture and areas within this zone see very little to no precipitation and something like this can vastly affect snowfall totals.

Given how close to the coast this system will track and with warmer air that will be working into portions of the region, this will create a tight baroclinic zone (greater temperature difference over a small area).  This also works to vastly increase lift and forcing, just to the west of this zone and where this zone sets up is where the heaviest snows and higher totals will occur.

With a potent storm system which will continue to strengthen as it works up the coast this will also increase the pressure gradient across the region and a period of strong winds will be introduced.  Winds could gust as high as 35-45 mph region wide, and especially across the coast.  This will lead to isolated to scattered power outages along with perhaps blizzard conditions in some spots.

The first impacts from the storm will begin very early Thursday morning, right around dawn or just a bit after with everyone starting off as snow.  The timing of the storm will likely lead to a great deal of school cancellations throughout the region.  For those heading to work the travel commute will deteriorate very quickly and expect numerous delays.

The height of the storm will occur between about 10 AM and 10 PM.  During this time snowfall rates may approach 3''/HR in the areas where the heaviest banding occurs.  Winds will also increase as well as the afternoon goes on with gusts approaching 35-45 mph, especially towards the coast.  For areas south and east snow the snow will eventually transition over to sleet and then rain thus the lesser snow totals.

Given everything mentioned above, this is what I'm currently thinking as far as snowfall totals go:

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.