Another significant snowfall on the way for Freehold

Here we go again!  Another major winter storm has a target for the northern Mid Atlantic with the potential for another one to two feet of snow for many locations in the New York City and Philadelphia metropolitan area along with very strong winds and near zero visibility for Wednesday morning.

The water vapor satellite image this morning displays all the players for this major winter storm.  The first feature to take note of is the strong upper low, enhanced by the last major low pressure system, over the Canadian Maritimes.  That is the 50N/50W upper low that is key for any significant winter storm.  This upper low is in a near text book position to support a major to potentially historic winter storm for the region.  The position of this feature on all guidance strongly supports a stormy track from North Carolina to the bench mark.  

Meanwhile the phase is starting to take shape over the central Plains between the Sub Tropical disturbance and Polar disturbance.  Note the streak of moisture racing out of the Southern Plains and into the Tennessee Valley.  This is the contribution from the Sub Tropical jet stream, which will become even more enhanced as the Polar disturbance, which is already rather intense, interacts with this jet stream of moisture.  Now, before going into the details of this storm, I should warn that I still think there are some issues with this storm that will need to be watched.

First, the position of the upper low on Tuesday evening is going to be very important.  The overall idea on the model guidance is that the trough axis of this intense upper low goes negative, which drives very strong PVA towards the Mid Atlantic coast.  Or in other words, very strong lifting is driven towards the coast leading to rapid low pressure development.  The speed and intensity of this transfer of energy from the old primary over the Ohio Valley to the new coastal low off the North Carolina coast will be extremely important.  If the transition is slower than forecasted, then several issues will unfold with the development of a heavy snowfall.  For one, if the 850 MB low is slow to develop along the coast, then much warmer air may work into the coastal plain causing a larger area of mixing than currently expected.  Or if the 700 MB low is slower or further west, then a dry slot may significantly cut snowfall totals in half.  These issues should be ironed out in the next two model runs this morning and tonight.  The trends seen on the 06Z guidance may be illustrating these issues or simply be a case of model error.  However, these issues will have to be ironed out.

The way I see this storm working out is that the coastal low pressure system will bomb out to the east of the New Jersey coast, reaching a pressure of around 978 to 972 MB by Wednesday afternoon.  This low pressure system will be capable of very strong wind gusts and coastal flooding.  The storm will also feature an area of intense deformation, which will lead to bands of heavy snowfall developing.  Temperatures will be falling through the day on Wednesday, causing snow ratios to rise from initially 10:1 up to 20:1 by storms end.

As of this morning, here are the storm impacts I envision for this winter storm.  High winds and coastal flooding will be an issue throughout the coast line regardless of precipitation type.  The high winds will range from 15 to 30 mph sustained with gusts over 40 mph expected.  The 950 to 850 MB low level jet stream is expected to drive right into the central New Jersey coast on Wednesday morning right through the evening hours, supporting the potential for wind gusts up to 70 mph at times, especially in areas of strong mesoscale banding.  As for precipitation types, some warmer air is expected to work into the lower and mid levels of the atmosphere over southeastern Long Island and southern New Jersey, leading to a mix of snow, sleet, and rain at times.  This wintery mix will hold down snowfall accumulations, however all precipitation will change over to snow by Wednesday afternoon.  Otherwise, intense heavy snowfall is expected throughout the New York City and Philadelphia metropolitan areawith the potential of 1 to 2 feet of snow, near zero visibility at times, and very unfavorable driving conditions for the morning and evening rush hours over the region.  The difference in snowfall totals in this area will be determined by location of mesoscale banding features and the development of convective snowfall.  Where these features set up will determine what location gets the most snowfall.  Other considerations will be the speed in which temperatures at the surface and 850 MB falls to impact snow ratios in locations.

This storm is expected to exit late Wednesday night into early Thursday morning with a few lingering snow showers thereafter.  High pressure will take hold on Thursday afternoon through Saturday with clear skies and cold temperatures.  Temperatures through the period will average slightly below normal with many locations remaining in the upper 20's to mid 30's for afternoon highs.

Another area of low pressure may potentially impact the region on Sunday.  This low pressure system is currently expected to remain well to the south at this time, but may more far enough north to introduce some snow showers into the region.  Otherwise, the northern Mid Atlantic will get a few days rest after two major snow storms in a 5 day span.

Trust in NY NJ PA Weather for the best analysis and live coverage of major winter storm impacts throughout New Jersey!