Strong coastal storm to bring significant impacts to southern New England 3-6 to 3-8/13

A storm system which is bringing significant snowfall accumulations to portions of the mid-Atlantic will move off-shore and continue to rapidly strengthen as it begins to shift towards a more northerly track.  Over the past few days computer forecast guidance has continued to indicate a track further and further northward and northward enough to where we will not only see impacts but significant impacts.  These impacts will range from accumulating snowfall, to periods of heavy rain along the SE coast, to strong winds, to scattered power outages, to coastal flooding.  Once again this is a highly complex forecast which is sure to give us surprises.  With this let's break everything down.

Precipitation may begin breaking out as early as mid to late afternoon on Wednesday and since boundary layer temperatures will be on the warm side this means precipitation initially begin as a mix of rain or snow or perhaps even all rain, especially along the coast.  As we move through the late afternoon hours and through the evening, as the storm continues to rapidly intensify, this will help to usher in some much colder air from the north and temperatures will cool to the point to where precipitation should transition over to all snow, even down to the coastline of CT.  Out across coastal areas of RI and along the Cape, however, precipitation may have a more difficult time transition over to all snow, especially b/c the system is expected to become quite strong that will will actually wrap warm air into these areas.  The heaviest of the precipitation  should occur during the late evening and overnight hours, however, across eastern MA and parts of RI, heavier precipitation will last through much of Thursday morning as the storm stalls out.

Snowfall:

It appears that much of the region will be seeing at least several inches of accumulating snowfall with the exception of the immediate coastline of RI and the Cape where mixed precipitation will hold down totals.  While some latest guidance is actually coming in colder the snowfall ratios are a little unclear at this point and would have a fairly impact on the overall snowfall totals.  Right now, I would go with snowfall ratios of around 10:1 and perhaps as high as 12:1.  As of now I would expect the highest snowfall totals to occur across NE CT extending northeastward into Worcester county MA and into southern NH and even as far east as the Boston area.

Rainfall:

For areas along coastal RI and along the Cape rainfall totals could reach or exceed 1-2''.  This could lead to pockets of isolated flash flooding, especially with an already saturated ground.  It's also possible areas along the immediate coastline of CT experience more in the way of rainfall than snowfall and this will be a very challenging forecast for this area.

Strong Winds:

We will also be experiencing a period of strong/damaging winds with this system, especially out across eastern MA, RI and SE CT. Here winds will be sustained between 30-40 mph with wind gusts as high as 60 mph possible.  This will lead to pockets of tree/wire damage and will lead to scattered power outages.  While the number of power outages shouldn't be extreme, we can't rule out some widespread power outages if the snow is wet and we get significant accumulations of wet snowfall.  Elsewhere across the region, winds will be sustained 15-25 mph with gusts s high as 45 mph.

Coastal flooding:

Coastal flooding is expected to be a major concern with this system across coastal areas of eastern MA and the coast of CT.  Coastal flooding will be at it's worst during the high tide cycles of Thursday morning and Friday morning with the most severe of impacts possibly occurring during Friday's cycle.  This could pose a significant risk for anyone along the immediate coastline and for structures close enough to the water.  Some areas along the immediate coast could end up with as much as 2-3 feet of water and perhaps even as much as 4-5 feet of water.  This will be a major concern and could pose a life threatening situation for anyone right along the immediate coast.

Below is snowfall forecast: