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Forecast: Snow will overspread the North Country during the late-morning and
early afternoon period tomorrow.  It will quickly become moderate to heavy
at times, especially along the spine and eastward.  Snow will continue into
Sunday night with the heaviest snow falling during late Sunday afternoon and
evening (1"/hr rates).  Winds will be increasing throughout the storm and
will become strong on Sunday evening and night.  Travel will be very
difficult with whiteout conditions possible.

Snow tapers off late Sunday night in the larger valleys but upslope will
continue in the usual areas through Monday afternoon.  Winds will continue
to rip on Monday and wind hold for lifts is likely Monday morning.  It will
also be very cold with wind chills well below zero.

Total Accumulations from 12pm Sunday through 6pm Monday will range from
8-14" across much of Vermont, including even S.VT, with the higher double
digit amounts along the Green Mtn spine from Sugarbush to Jay Peak thanks to
upslope enhancement late in the storm.  For the immediate Champlain Valley,
5-10".

Discussion: A strong mid/upper level trough is currently working its way
across the midwest and can easily be seen on the WV loop.  This will work
its way eastward tonight and as it attempts to dig in over the Lakes it will
develop a strong 150kt upper level jet across the Ohio Valley.  This will
excite cyclogenesis when it hits the thermal boundary draped from the
Mid-Atlantic back into the Ohio and Tennessee Valleys.  The first low will
end up getting ripped northward as the shortwave moves in, but it'll lose
its punch quickly as the baroclinic zone is forced eastward. 

As the baroclinic zone shifts eastward, a surface low will form near the
Delmarva and track NE towards Cape Cod.  The Lakes low will weaken and fill
as the coastal low becomes the dominate low.  It will be rapidly
intensifying as it passes Cape Cod and it should reach the maritimes as a
near 970mb bomb.  

Snow will overspread the region on a strong SE flow during the day tomorrow.
 Areas along the Green Mtn spine and immediately eastward will see enhanced
snowfall from the get-go thanks to this upsloping flow.  I am concerned
about downsloping along the western slopes and Champlain Valley during the
first part of this storm until winds turn more out of the north.  Snow could
fall at an inch or two per hour across the Spine and eastern Vermont with
rates of a 1/2-1" per hour at storm's peak west of the spine...this will
happen as the low bombs out passing Cape Cod/BOS area when copious Atlantic
moisture is advected over the cold dome.  Ratios during this portion of the
storm should be in the 12:1 range.    

With no blocking mechanism and a +NAO, this coastal low will be a fast
mover.  However, with rapid deepening and a 1032 High building in behind it,
the winds will steadily increase throughout the storm.  As the low passes us
to the east, winds will pick up to 25-40mph especially over the higher
terrain.  H85 winds increase late Sunday night to 40-50kts and continue into
Monday afternoon.  Considerable blowing and drifting of the snow is expected
along with wind holds on the ski lifts come Monday morning.

As the synoptic stuff dies down late Sunday night, upslope will start
cranking, especially Monday morning as the best H85 wind and H7 moisture
interact.  Temperatures in this layer are progged to be -14C to -18C which
will provide good dendrite growth with snow-water ratios increasing to
15-20:1 (the usual upslope product).  CSTAR research indicates significant
upslope (6"+) occurs when favorable conditions exist for 12 or more hours,
however with this fast moving system we won't reach that.  Therefore, after
synoptic snows end (6-10" at the ski areas) I'm anticipating another 3-6" of
upslope...thus am expecting 10-14" along the spine.

This should be another fun storm to watch evolve because it'll be a dynamic
but fast-moving system.  If only we had a -NAO or some blocking mechanism
downstream this would average 1.5 feet or higher rather than 1 foot.  You
can't ask for a better track for a bombing surface low pressure system,
there's just nothing to slow it down.

I look forward to the reports from ski country tomorrow and Monday.

Enjoy,
-Scotty B. 
    
         

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