The latest model runs from the operational NAM (North American Mesoscale Model) indicate increasing confidence for a major northeast snowstorm this Friday. The NAM model for the last day has indicated that a low pressure area moving through the Midwest toward New England will help to create another low pressure south of Long Island, NY. This new and strong low pressure area will travel over Cape Cod northeast over Nova Scotia.
Surface low pressure development will be aided by a strong jet stream aloft along with strong positive vorticity advection ahead of the low pressure in the middle of the troposphere. Thankfully, upper level winds will help to guide this low pressure area away from southern New England quickly before too much damage can be done.
Since the low pressure area appears to travel fairly close to southern New England, warm air would protrude into that area, which would set up a coastal front. Along this coastal front increased snowfall totals would be likely.
However, the GFS keeps the newly developed low pressure area further off of the coast than the NAM as of the 12Z and 18Z model runs. It seems as if the GFS and NAM have held their model solutions constant for the last couple of runs. At some point they will have to converge…
Based upon the NAM forecast, southern New England could pick up 6-12 inches of snow with the most snow falling in interior sections while lesser snows would fall along the coast and toward the Cape and Islands.