NY NJ PA Weather Forecasts

Evening Thoughts: Dance Of The Models

8:46 PM

The models did this.  The models did that.  We have a had a lake cutter, a major snow storm, a rain storm, and even no storm at all.  So clearly, we should hug the models from run to run.  

The basic overall pattern idea has not changed one bit.  The 12Z guidance theme was basically what I’ve been describing with several different results.  The operations GFS from the 12Z run was suppressed to the south for much of the period of Sunday night through Thursday.  The ensemble guidance was further north.  The ECMWF has a lot of moisture in the mid levels and a strong thermal gradient, but very little moisture.  I am very suspicious of the idea of RH over 75% at 850 MB and over 90% at 700 MB over an Arctic air mass on Sunday evening through Thursday.  I think there is more precipitation from this set up than the ECMWF is suggesting here based on the type of air mass on the way and the amount of moisture at the mid levels.

The basic idea I had this morning has not changed.  At this time, I do not believe this period (Sunday night through Thursday) is a big precipitation maker for locations from New York City on northward.  This set up clearly is directed from central New Jersey through the Philadelphia metro.  In THIS forecast area, it is these locations that would have the best chance for snowfall.  

I will likely put out snowfall maps for Sunday into Monday by tomorrow evening after a lot of thought.  I don’t expect to put out snowfall amounts above 3 inches as I’m expecting only very light snow/flurries to impact the southern forecast area.  What’s important on Sunday is to examine just how much influence the high pressure system will have in suppressing precipitation to the south.  In similar situations besides PDII, precipitation tends to move slightly further north than modeled.  

Going forward for the end of the week, again.  No real changes in the actual forecast.  The best potential remains from central New Jersey through the Philadelphia metro for measurable snowfall.  There is potential for a heavy snowfall, but a lot of that will be determined by the strength and position of individual disturbances that eject eastward in this pattern.

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