NY NJ PA Weather Forecasts

Active Pattern Continues For Next Week

7:30 AM

The new year is certainly starting off with a bang this year, unfortunately that does not mean snow for all. 

The main theme through this period will be the changing Pacific and Atlantic patterns.  The negative NAO block will begin to weaken, however already the ECMWF is backing away from the complete collapse idea and tries to bring a weak negative NAO block back towards the end of the period.  Meanwhile, the GFS guidance has backed away from the idea of a strong coastal solution for Tuesday and Wednesday.  Let’s break down the forecast!

High pressure will once again take a short stop over the forecast area on Monday with clear conditions.  The air mass is not all that cold, however near to slightly below normal temperatures can be expected on Monday.  Meanwhile, an area of low pressure will be organizing over the southern Plains and move towards the Ohio Valley.

Initially on Tuesday morning, the majority of the forecast area will be cold enough to support some light snow.  In fact, as the low pressure system over the Ohio Valley continues to intensify, strong isentropic lifting will likely produce a period of light to moderate snow over the entire forecast area including southern New Jersey with the potential for some light accumulations along the coast and even a moderate to significant accumulation of snow and ice over the interior.  The tight thermal gradient at the surface and aloft will support a coastal development, however the primary will remain over the Ohio Valley.  This means that despite the cold start, the precipitation will change over to rain as the 850 MB low intensifies to the west of the forecast area.  The interior will be a bit more tricky as I think there is a higher potential for a mix of snow, sleet, and freezing rain for northeastern Pennsylvania, the Hudson Valley, northern New Jersey (basically Sussex County), and interior Connecticut. 

By Tuesday night and Wednesday, the coastal low does take over as the strong 500 MB upper low races through New England.  Really, the primary low takes a jump towards the coast as the coastal low that develops begins to fade away.  However, the results will be the same.  The precipitation over the interior will change back to snow before ending with a slight additional accumulation while the rest of the forecast area ends as rain before any cold air reenters the forecast area. 

So what needs to change to allow for this storm to be more significant?  Well for one, the upper low over Alaska needs to break down faster to allow the ridge in the West to build.  I don’t see that happening.

Second, the 50/50 low needs to remain stronger, which would be possible if the upper low over Alaska weakened faster.  Again, I don’t see that happening right now.  I can bet that those looking at the 06Z GFS have some hope, but I wouldn’t count on that trend unless the guidance is supported by the 12Z GFS AND ECMWF going forward. 

The pattern goes cold again with another interesting potential storm for the upcoming weekend as the ridge in the West rises and a weak negative NAO is in place.  Remember, the best storms for the forecast area have occurred durring changing or weak negative states of the NAO, so this period bares watching.

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