Saturday, December 22, 2012

Christmas Day Snow - An Early Look

UPDATE (12/22 - 5PM) - What a horrible run of the models today for snow lovers.  After last night's overnight EURO run dropping high-end advisory to low-end warning snows along the Mass Pike right into Boston, today's EURO nearly dropped the system off the radar - pun intended.  Now the early evening model runs are also showing this system losing steam as it heads out of the OH Valley and through PA.  Because of the weaker life and lower rates, it will likely warm into the middle 30s during the daytime on Christmas Day too, which will also limit accumulations near the coast.  Perhaps the Worcester Hills could still be able to pick up an inch or two, but even that might be generous with the unfortunate trends today.  We are still about 60-72 hours away, so the models could turn back to the snowier/more amplified scenario later tonight or during tomorrow.  However, in my experience, once these start to trend weaker at the 'last minute', then we probably will not return to the solutions that were giving much of the region a few to several inches of snow overnight Christmas Eve and Christmas Day morning.

We still have the late week system too though? Sorry to be the bearer of bad news, but all computer models are focusing on that system to amplify rather quickly once it is in the TN Valley.  Consequently, there is not much of a handoff to the secondary that 'was' developing off the Mid Atlantic coast in previous days' runs. Also, the high pressure system to the north of us is weaker and further west (north-northwest) too, which also allows this thing to push up the spine of the Apps.  A secondary low pressure surface reflection tries to show later in the game near NYC, but even that gets pulled WNW on  most of the computer models, flooding much of SNE with warm maritime air that changes any brief period of snow at the onset to heavy rain with strong southeasterly winds.  Even ski country might have a hard time dodging the rain drops with this one if it verified as depicted on the models today.  This one is still about 4.5 to 5 days out, so we still have time to work on the details, but the trend is definitely not our friend (if you're a snow lover anyway).

Last minute shopper?  Tomorrow should be a fine day (weather-wise at least) to get to the malls.

00z GFS - 12-22-2012
I am updating the blog from last night's optimism regarding the potential snow for Christmas Day.  Well, it now appears more likely after tonight's late hour model runs.  Last night's EURO run and this afternoon's EURO run gave much of SNE several inches of snow, away from the Cape and Islands.  Now the American model (GFS) is coming on board with a snowier solution too as depicted above.  

The GFS still keeps this as mostly a Pike-south event, but the EURO (admittedly a more reliable model) gets at least a few inches up across the MA/NH border.  Right now I would have to go in the middle of the two, but tend to favor the EURO solution.  The newest EURO solution comes out at 1:15AM, so we will have to wait and see if it keeps the Christmas Day snow hope alive.  The trends are encouraging for snow lovers this evening though across all fronts.  The snowier models are giving this low pressure system time to develop and amplify off the NJ/LI coasts, so this will only contribute to a widening snow band that reaches across much of SNE.  

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