powderfreak
New member
12z Models are in...12z NAM gives VT under a half inch of quantitative
precipitation forecasted (QPF) and its all snow. It shunts off all heavy
precipitation to the east of the low pressure system. It has been doing
this at various runs throughout the past two days. The 12z GFS gives VT 1-
2" of QPF, with over 6" of snow from the Green Mtn spine westward into
NY. Its model surface reflection print out has around .4 QPF as rain and
then 1.3" QPF as snow with high probabilities of thunder snow. This
senario would include rain breaking out early Tuesday morning, changing to
snow in the afternoon, then snowing at 2" per hour with high winds during
Tuesday evening. Sounds nice. However, I'm becoming increasingly
concerned with what the NAM has been showing with very little precip being
thrown westward into the cold air in classic nor'easter fashion.
The NAM has a less phased senario which means a fast moving storm system
(12hrs in and out) becomes even more progressive. It seems to lack a
deformation zone (and associated deformation dynamics) and the best RH and
lift stays in the eastern/warm side of the storm. The dynamics of the NAM
are not conductive to heavy precipitation west of the Berkshires into the
White Mountains. It has a raining in the warm sector but drying out
exceptionally quick in the cold sector. So you could go from 38F with
rain to 32F in a matter of minutes but the precipitation shuts off just as
fast. I'm very concerned with this situation in that NNY and VT may be
missed all together, only to see some heavy rain in NH and ME before it
shuts off as soon as cold air comes in.
Residual moisture and cold air advection will likely produce some mountain
snow either way behind the storm...but it might not be a foot of heavy
paste that would lay a nice base down. It would likely be 3-6" of
lighter, fluffier stuff. I'm very interested in seeing the 18z models and
also how the HPC deals with it.
So right now, I'm weighing in at 70% chance of no snow with the system
itself and then moist low level Cold Air Advection bringing up to 6" in
snow showers and squalls across the Adirondacks, central and northern
Green Mountains, and White Mountains.
Thanksgiving Day clipper looks juicy with secondary development off the
coast...and then it cuts off at 500mb and spins snow showers and squalls
around New England through the weekend. The initial system, however,
looks to bring a round of briefly heavy snowfall during the day on
Thursday across most of NY, VT, MA, NH, and ME. Looks like a decent
chance for 6" of snow in a lot of spots on Thursday. Temps should be cold
enough for all snow everywhere except south of a Boston to Hartford
line...and maybe up into southern Maine depending on how strong the
onshore flow is and if it can warm up the boundary layer enough.
Skiing on Friday-Sunday could be very nice with on and off snow showers
and squalls bringing isolated deep, fluffy accumulations as temperatures
fall to late December levels.
More later,
-Scott
precipitation forecasted (QPF) and its all snow. It shunts off all heavy
precipitation to the east of the low pressure system. It has been doing
this at various runs throughout the past two days. The 12z GFS gives VT 1-
2" of QPF, with over 6" of snow from the Green Mtn spine westward into
NY. Its model surface reflection print out has around .4 QPF as rain and
then 1.3" QPF as snow with high probabilities of thunder snow. This
senario would include rain breaking out early Tuesday morning, changing to
snow in the afternoon, then snowing at 2" per hour with high winds during
Tuesday evening. Sounds nice. However, I'm becoming increasingly
concerned with what the NAM has been showing with very little precip being
thrown westward into the cold air in classic nor'easter fashion.
The NAM has a less phased senario which means a fast moving storm system
(12hrs in and out) becomes even more progressive. It seems to lack a
deformation zone (and associated deformation dynamics) and the best RH and
lift stays in the eastern/warm side of the storm. The dynamics of the NAM
are not conductive to heavy precipitation west of the Berkshires into the
White Mountains. It has a raining in the warm sector but drying out
exceptionally quick in the cold sector. So you could go from 38F with
rain to 32F in a matter of minutes but the precipitation shuts off just as
fast. I'm very concerned with this situation in that NNY and VT may be
missed all together, only to see some heavy rain in NH and ME before it
shuts off as soon as cold air comes in.
Residual moisture and cold air advection will likely produce some mountain
snow either way behind the storm...but it might not be a foot of heavy
paste that would lay a nice base down. It would likely be 3-6" of
lighter, fluffier stuff. I'm very interested in seeing the 18z models and
also how the HPC deals with it.
So right now, I'm weighing in at 70% chance of no snow with the system
itself and then moist low level Cold Air Advection bringing up to 6" in
snow showers and squalls across the Adirondacks, central and northern
Green Mountains, and White Mountains.
Thanksgiving Day clipper looks juicy with secondary development off the
coast...and then it cuts off at 500mb and spins snow showers and squalls
around New England through the weekend. The initial system, however,
looks to bring a round of briefly heavy snowfall during the day on
Thursday across most of NY, VT, MA, NH, and ME. Looks like a decent
chance for 6" of snow in a lot of spots on Thursday. Temps should be cold
enough for all snow everywhere except south of a Boston to Hartford
line...and maybe up into southern Maine depending on how strong the
onshore flow is and if it can warm up the boundary layer enough.
Skiing on Friday-Sunday could be very nice with on and off snow showers
and squalls bringing isolated deep, fluffy accumulations as temperatures
fall to late December levels.
More later,
-Scott
