A
Anonymous
Guest
I posted this on SKIVT-Listserve but also wanted to post it here. I did a run down of my thinking on Thursday night to what actually happened:
>Ok. This one is sneaking up on and I know inquiring minds want to know
>where the most snow will be. To be honest with you, I believe the NWS is
>overdoing this system. I am not seeing any model guidence that indicates
>heavy snow as far south as they show. For one, thicknesses will be a
>little higher than I'd like. The atmosphere will be marginally cold with
>temps at the surface in the middle 30's as precip moves in. 850mb temps
>(5,000ft roughly) are going to be marginal with the freezing line right
>along I89 as precip moves in. Currently the 850 freezing line is in
>Canada. As the heaviest precip moves in, the column should cool enough
>for all snow but it is still marginal in central Vermont. I'm seeing a
>strong chance for sleet from the Mad River Valley southward. I do not
>think freezing rain will be too much of an issue...temps will be hovering
>around the freezing mark. This looks like a situation where in times of
>heavy precip you are seeing snow and at times when its light or spotty you
>are seeing light rain or ice pellets.
Read that above paragraph. I should've gone with my pessimistic side.
Basically I saw a lot of factors that would go against snowfall...the most
important factor: the temperature profile. Ground temps were borderline
as was the entire column straight up to 5-7,000 feet. 1-2 degrees and
this was going either way...it went the wrong way. Also, the last
sentence of that paragraph says it all. Heavy precip = Snow. Light or
spotty precip = rain/ice pellets.
>With that said...the models will likely trend southward with the system,
>just a tad. The high pressure system is strong in southern Canada but the
>air down here is not as dry as I would like it to be to really bring temps
>down at the onset of precip.
So for my forecast, I went with the trend of this moving southward.
However, now looking back at it, I made a huge mistake here because I
should've known it would come northward a little bit. The models always
pull this. For 3-5 days a storm looks to be going one way...and all
models are pretty nmad sure it'll happen that way. Then there's a drastic
switch, which we saw on Thursday (and thus Winter Storm Watches). Then
models bottom out with the extreme version and move back ever so slightly
toward the original situation. I should've seen that one coming.
>Look for rain/sleet pellets to fall during
>the day tomorrow in the valley locations and southern Vermont...with snow
>in the far north if precip makes it up there in the Stowe-Jay region.
>Friday night we get some very strong Omega lift across the region. That
>lift then moves into northern Vermont and parks there. What goes up, must
>come down. This is where the coma head of the precip will likely be.
>Central and Southern regions might become dry slotted with spotty
>precipitation early on Saturday while the northern areas (in the coma
>head) could be seeing banded snowfall with rates up to 2"/hr.
There was some intense banding last night, but mostly extreme northern VT
and northern New York up into Canada. What happened was we had light rain
for most of the night from 6pm until around 10 or so in Burlington. Then
the strong Omega lift moved northward across the area and with that strong
precipitation the rain changed to snow. By this time, however, the ground
was wet, warm, and the snow just could not accumulate fast. This was also
in the area of max snow growth aloft. Everything came together for some
heavy snow for a few hours last night. I was outside around 11 last
night, and in Burlington the flakes were the size of half dollars and it
was coming down hard enough to accumulate even with the warm, wet ground.
But then as the bands of heavy precip moved through, it would change back
to a light rain. So again, had it been 31 degrees and not 33...we
would've been golden.
>I believe this system will be a little further south and could
>move this band into northern NY or VT (might be more wishful thinking but
>this seasons trend would favor it). With the coma head, deformation axis
>during Saturday , very strong lift, a colder temp profile (higher snow
>ratios as well), and overall more precip, I feel the Bolton-Stowe-Smuggs-
>Jay region will see 12-18 inches by Sunday morning with 6-12 Sugarbush-MRG
>zone. Also, in NY, the northern Adirondacks (Whiteface) would also be in
>the 12-18 inch zone.
Ok...actual snowfall wasn't even 50% of that. Although it isn't Sunday
morning yet, and maybe another couple inches could fall through tonight in
wrap around moisture, my totals aren't gonna come close. Liquid amounts
are still right, however. I saw a bunch of reports of .6 to even 1.5
liquid inches so far.
>That is my thinking right now. I still think the NWS might be a little
>too high on snowfall in the major valleys (Champlain, CT River, ect) as
>well as a little too gung ho on precip staying all snow in the Mad River
>Valley region but we will see.
Ahhh...When will I learn to not let the skier-I-want-lots-of-snow get in
the way of my forecasting? When will I learn that if I feel necessary the
NWS isn't always right?
Next Storm Please.
-Scott
>Ok. This one is sneaking up on and I know inquiring minds want to know
>where the most snow will be. To be honest with you, I believe the NWS is
>overdoing this system. I am not seeing any model guidence that indicates
>heavy snow as far south as they show. For one, thicknesses will be a
>little higher than I'd like. The atmosphere will be marginally cold with
>temps at the surface in the middle 30's as precip moves in. 850mb temps
>(5,000ft roughly) are going to be marginal with the freezing line right
>along I89 as precip moves in. Currently the 850 freezing line is in
>Canada. As the heaviest precip moves in, the column should cool enough
>for all snow but it is still marginal in central Vermont. I'm seeing a
>strong chance for sleet from the Mad River Valley southward. I do not
>think freezing rain will be too much of an issue...temps will be hovering
>around the freezing mark. This looks like a situation where in times of
>heavy precip you are seeing snow and at times when its light or spotty you
>are seeing light rain or ice pellets.
Read that above paragraph. I should've gone with my pessimistic side.
Basically I saw a lot of factors that would go against snowfall...the most
important factor: the temperature profile. Ground temps were borderline
as was the entire column straight up to 5-7,000 feet. 1-2 degrees and
this was going either way...it went the wrong way. Also, the last
sentence of that paragraph says it all. Heavy precip = Snow. Light or
spotty precip = rain/ice pellets.
>With that said...the models will likely trend southward with the system,
>just a tad. The high pressure system is strong in southern Canada but the
>air down here is not as dry as I would like it to be to really bring temps
>down at the onset of precip.
So for my forecast, I went with the trend of this moving southward.
However, now looking back at it, I made a huge mistake here because I
should've known it would come northward a little bit. The models always
pull this. For 3-5 days a storm looks to be going one way...and all
models are pretty nmad sure it'll happen that way. Then there's a drastic
switch, which we saw on Thursday (and thus Winter Storm Watches). Then
models bottom out with the extreme version and move back ever so slightly
toward the original situation. I should've seen that one coming.
>Look for rain/sleet pellets to fall during
>the day tomorrow in the valley locations and southern Vermont...with snow
>in the far north if precip makes it up there in the Stowe-Jay region.
>Friday night we get some very strong Omega lift across the region. That
>lift then moves into northern Vermont and parks there. What goes up, must
>come down. This is where the coma head of the precip will likely be.
>Central and Southern regions might become dry slotted with spotty
>precipitation early on Saturday while the northern areas (in the coma
>head) could be seeing banded snowfall with rates up to 2"/hr.
There was some intense banding last night, but mostly extreme northern VT
and northern New York up into Canada. What happened was we had light rain
for most of the night from 6pm until around 10 or so in Burlington. Then
the strong Omega lift moved northward across the area and with that strong
precipitation the rain changed to snow. By this time, however, the ground
was wet, warm, and the snow just could not accumulate fast. This was also
in the area of max snow growth aloft. Everything came together for some
heavy snow for a few hours last night. I was outside around 11 last
night, and in Burlington the flakes were the size of half dollars and it
was coming down hard enough to accumulate even with the warm, wet ground.
But then as the bands of heavy precip moved through, it would change back
to a light rain. So again, had it been 31 degrees and not 33...we
would've been golden.
>I believe this system will be a little further south and could
>move this band into northern NY or VT (might be more wishful thinking but
>this seasons trend would favor it). With the coma head, deformation axis
>during Saturday , very strong lift, a colder temp profile (higher snow
>ratios as well), and overall more precip, I feel the Bolton-Stowe-Smuggs-
>Jay region will see 12-18 inches by Sunday morning with 6-12 Sugarbush-MRG
>zone. Also, in NY, the northern Adirondacks (Whiteface) would also be in
>the 12-18 inch zone.
Ok...actual snowfall wasn't even 50% of that. Although it isn't Sunday
morning yet, and maybe another couple inches could fall through tonight in
wrap around moisture, my totals aren't gonna come close. Liquid amounts
are still right, however. I saw a bunch of reports of .6 to even 1.5
liquid inches so far.
>That is my thinking right now. I still think the NWS might be a little
>too high on snowfall in the major valleys (Champlain, CT River, ect) as
>well as a little too gung ho on precip staying all snow in the Mad River
>Valley region but we will see.
Ahhh...When will I learn to not let the skier-I-want-lots-of-snow get in
the way of my forecasting? When will I learn that if I feel necessary the
NWS isn't always right?
Next Storm Please.
-Scott
