Thursday, November 20, 2008

12z GFS & ECMWF

The 12z GFS has edged back closer to its previous solutions and still doesnt completely agree with the Euro. Precipitation is back to being more frontal, and temperatures are generally colder for SNE, making it a mostly snow event. The 12z ECMWF is further south, colder, and with more snow, especially for the interior. Based on these couple of runs, I believe the 06z GFS is too warm, but it is part of a trend toward the ECMWF with respect to the H5 Low. Much depends on when the trough tilts negative. As the GFS trends toward the Euro, there are a couple of possibilities for the surface low track, and one of them is through E NY resulting in a lot of rain, and a lot less snow. The 12z model consensus places secondary low pressure south of Long Island and tracks it over SNE, which would result in a rain/snow mix Monday afternoon, changing to snow for Monday Night and into Tuesday, with mainly rain inside of the I95 corridor.

I am very confident now in at least .25" of water equivalent, and measurable snow accumulation is looking alright for Monday Night and Tuesday.

There is a chance for a delay or cancellation on Tuesday. That will need to be watched closely. The antecedent cold will make roads unusually suseptible to accumulation for the time of year ... that's if we get snow.

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