Wednesday, December 21, 2011

12/23 - possible mix or snow

12-23 reality. Temps in the mid 40's, rain.

12-22 - So close...

Almost all models have the 850 line splitting CT, with the NAM still south of CT, but moving north each run. However, the temp profile is not favorable for snow, unless it comes down real hard and draws colder air to the surface. Any precip in the late morn may end as wet snow. So while a sloppy morning commute would not surprise me, it is unlikely. GFS and NAM still have snow on their maps too. 12z Euro now much warmer, has .5" of all rain with 850 at 1c.



Yet the 18z nam comes in even warmer, with very little snow for us, if any. Plus its really warm out, and the system is juicy and I think heading further west than progged. Oh well. Not much support anymore from the models for accumulating snow, just some wet flakes or flurries afterwards. Might as well keep it warm.
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12-21 - with all the focus on sunday's event, friday's event is sneaking up and getting colder each day. All models have some precip falling on friday. So lets look at r/s lines. 540 thicknesses are all north, due to the ground level being warmer. This means either rain, mix, or non accumulating wet snow. Freezing line at 850mb (5,000 ft) looks like the following
Euro - right around I84, clipping sussex county, nj (dxr is actually .1 and 0 for this time frame) - meaning rain for dxr. This is a warmer solution from previous run. Euro ensembles are much colder and give us a good snow storm 3-6 inches, if it doesn't melt.
NAM - 0z has 850 line south of CT, about I80 through nj.
NAM - 6z -colder with line south of LI, Sandy Hook, to Trenton
GFS - 0z - north of CT, doesn't move south until the early afternoon, which is after the precip ends. Ensembles have a rain to snow event, not likely any accum
GFS - 6z, colder with line now about I84, clipping sussex county. Very much like 0z euro Ensembles have a good snow storm. 4"?
JMA - only resolves in 24 hrs, but looks to be warm for the period, with the line crossing south of dxr around 6am. could turn to snow.
CMC - line splits CT in half, gradually lowers through the event, mostly rain though.
SREF is bullish on snow for CT, sussex cty.

Afternoon update:
12z Nam colder with mostly snow now, although no accumulation other than a dusting per its map.
12z GFS - colder, 1-2 inches on its snow map, still starts mix goes to snow, but not too far off from 6z
CMC - line still splits ct, but still mostly rain
18z NAM -all snow 1-3
18z GFS - low comes out Del Bay and S of LI. 850 line still in CT, not far enough s for snow until near the end of the event. .75 qpf forecast. GFS snowmap has several inches, but ground temps are in the mid-upper 30s.

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