NY NJ PA Weather Forecasts

A Roller Coast For Temperatures And Snow For The Interior

Most of you are outside right now, and if you are in southern New Jersey you may be confused as to whether we are in April or December as temperatures soar into the 60’s.  Well the party is about to come to an end as cold air breaks into the forecast area, but not before two separate storms impact the region first.

The best dynamics currently are lifting to the north of the forecast area, however heavier precipitation is redeveloping over Virginia and the Carolinas.  As we move forward into tonight and Thursday morning, I think the GFS and NAM QPF guidance is a bit over done.  I just don’t see the forecast area getting over 3 inches of rain over the next three days combined.  There may be some isolated locations, but not wide spread.  

So tonight the cold front presses south with colder air slowly bleeding into the forecast area.  However, the coldest air is not directed towards the forecast area, but south towards the Mississippi Valley.  This is due to the influence of the clipper that remains separate from the Gulf of Mexico low develop on Thursday.  As a result, the cold air will slowly build into the forecast area at the surface, which will still drop temperatures roughly 20 degrees between now and tomorrow morning.  

By Thursday morning, areas of rain will move through the forecast area as disturbances round the trough that is deepening.  The Gulf of Mexico low will be gaining moisture and strength as the thermal gradient tights over the East coast.  Now here is where the northern branch interacts with the Gulf Low in a negative aspect for snow lovers along the coastal plain.  The northern branch slightly pulls the upper low associated with the Gulf Low to the Northwest as the whole trough begins to tilt into a negative position.  This slight influence slows the progression of the CAA towards the coast and keeps the thermal gradient strong yet stagnant.  

By Thursday night, the rain/snow line will be located northwest of Philadelphia towards the NY/NJ/PA boarder and towards Poughkeepsie.  This is a fast moving storm due to the lack of blocking over the Canadian Maritimes, thus the surface low and 850 MB low will move quickly through the forecast area on Thursday night.  Most model guidance agrees with taking the 850 MB low over western New Jersey to Poughkeepsie, New York, and then over southern New England.  This track will all but guarentee an all rain solution for the majority of the forecast area.

However, the interior is another matter.  The cold air will not give much at the surface over northeastern Pennsylvania through the central Hudson Valley.  However the mid levels will warm to slightly above freezing.  The latest soundings forecast for these locations suggest a long period of sleet mixing in with the snow over many of these locations.  Where the mixing will occur the least is where I have the highest snowfall totals and then small accumulations as you move south and east.  

On Friday, the low pressure system will quickly move towards southern New England.  There is going to be a lot of mid level energy around the forecast area, so I kept lingering precipitation over the forecast area.  Temperatures will naturally fall behind the storm with a rather chilly day on Friday.  The precipitation will change over to all snow over the entire forecast area with possibly some lingering flurry action towards the coast.  I am concerned that a stronger disturbance behind this storm will touch off an area of light to moderate steady precipitation, thus the idea of an isolated inch over the coastal plain and parts of northwestern New Jersey and the southern Hudson Valley.

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