Tuesday, March 25, 2008

Snow coming.

Three more weeks of winter left.

We have great potential for snow and ice through the beginning of April. The NAO is negative, the AO is about to drop off by April 1st, and the PNA will soon be on the rise.

But lets talk about the short term.

Area of snow approaching the region right now with the leading edge currently near Albany, NY. This snow will reach the region after midnight and fall lightly through about 9am tomorrow, possibly changing to rain before ending. Accumulations should be under an inch. I added a slight chance of a delay - doubt it though.

More important is the storm I mentioned earlier for Friday into Saturday. A deformation zone setting up south of the region will guide a couple disturbances through the area Friday and Saturday. The latest trend has been to the south with colder air and little bit more moist. With a fairly tight temperature gradient associated with the deformation zone, isentropic lift looks good allowing for notable amounts of water equivalent during this period. At this point I am confident in greater than .5" and .75" to an inch or even more is looking more possible. Also looking more possible is a main ptype of snow for the duration. This could possibly even be a period of drier snow with higher ratios. All in all, I am gaining confidence in a 3-6 inch event here, and even 4-8 isnt looking too bad right now either. Right now we are in limbo between snow and sleet and also rain (mainly per the very warm NAM runs) and evening freezing rain. So icing could be a concern too. Side note: 18z GFS dumps a foot of snow on us, but keep in mind this is the 84hr range so one run is definitely not a lock. As for snowday potential. Timing is key, as the main event will likely be Friday Night. Could pull off an early dismissal on Friday.

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