Mailman

18z NAM:

The best part is... it's ONLY December.

12z Euro:

Oh man.  Euro has the heavy stuff over me at 36h.  

I'm going with 7-9" IMBY.  Interested to see what PBZ will have.

Totals are up from 6z on the 12z GFS.  Gotta figure PBZ will bump things up a bit.

12z RGEM:

12z HRRR:

High Rest NAM:

lol.

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
An upper level split-flow wave will cross the Ohio Valley into the 
mid-Atlantic Wednesday into Thursday, bringing a swath of moisture 
across the Upper Ohio. Associated sfc low pressure will develop 
across the upper Mississippi Valley before deepening off the 
Carolinas and riding up the Atlantic coastline. Transient left-exit 
and coupled jet support are progged to generate broad ascent to 
support mainly snow beginning Wednesday morning, then ramping up 
during the afternoon and overnight.

Significant uncertainty remains with regards to snow amounts across
the forecast area. Deterministic and ensemble guidance continue to 
support a large range in possible snow totals, primarily due to 
large differences in QPF amounts and placement of the sfc low to our 
east. The 00z ECMWF run in particular places the sfc low much farther
west and north than previous cycles, though without full EC ensemble
and other deterministic agreement, this was not enough reason to 
significantly inflate our official snow totals at this time. 

Some question also remains with the extent of warm advection across
the lower elevations of WV into SW PA on Wednesday afternoon/ early evening
as this could impact initial snow totals. With further penetration 
of warm air, some potential also exists for brief freezing rain 
across this area and into the lower ridges. However, the window for 
this is small, as more substantial warm advection would likely bump 
marginal sfc temperatures above the freezing mark. 

Rapid system progression also presents a barrier to high snow totals,
as the system quickly shifts off the coast early Thursday morning and
shuts off efficient snowfall. 

Highest snow totals remain over the Allegheny Mountains and ridges,
with lesser snow farther west. Confidence in 8+ inches of snow is
high enough across the higher elevations to support an upgrade from
Watch to Winter Storm Warning in those areas. With increased snow
amounts forecast farther west, the Watch was also expanded to include
areas including Pittsburgh. Lower confidence exists across the lower
elevations of Monongalia and Marion counties where warmer
temperatures will likely inhibit initial snowfall totals. Watches and
Warnings are in effect from 7AM Wed through 7AM Thu. Advisories will
likely be needed for areas farther west, especially if the upward
trend continues.

What the Canadian took away at 12z, we got back at 0z.  Nice!

Would be nice to see the GFS move closer to the others here within the next hour just to lessen my doubts a little.

3k NAM (warm tongue looms for me):

NAM looking good.

KPIT SREF Plume (15z -- mean 7.4"):

Hmph.  Just not enough liquid here.

High res NAM (still snowing at 60h):

NAM definitely doesn't have surface temp issues.

Their discussion is conservative, as well.  I miss Fries.

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Building high pressure on the van of deepening Plains low pres will 
bring dry weather for Tuesday with near-average temperature. That 
split-flow low is projected to dig over the Midwest by Wednesday and 
shunt a swath of mid level moisture over the Upper Ohio. Transient 
left-exit and coupled jet support are progged to generate broad 
ascent to support categorical POPs on Wednesday, mainly in the form 
of snow. System progression and temperature profile will be the 
inhibitors for snow acccumulation over much of the area as mid level 
warm advection degrades dendritic growth potential and as boundary 
layer warmth (32-34F) reduces impact potential. Nevertheless, an 
accumulation of heavy, wet snow is expected but with primary impact 
limited to the ridge-areas where a Winter Storm Watch remains in 
effect.