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First Winter Storm Threat for New England 2011/12 - II


Baroclinic Zone

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Looks similar to today's EC 48 hour prog. I don't like when the lows stretch; with these scenarios UVM is not strong and often times the NWP's OVER predict the UVM in these type scenarios.

The low isn't anymore stretched than other runs. In fact it's a bit more contracted because the s/w is sharper. The only reason people are *perceiving* it to be more stretched is because the program is drawing the low to one side of the pressure trough rather than in the middle like previous runs.

UVM is sure to be stronger this run for a few reasons: sharper trough -- stronger PVA, and stronger frontogenetic forcing with a tighter temp gradient in a stronger deformation zone.

This run would result in a more concentrated band of higher snow totals ... getting on up into the 6-12" range ... *NOT my forecast*

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The low isn't anymore stretched than other runs. In fact it's a bit more contracted because the s/w is sharper. The only reason people are *perceiving* it to be more stretched is because the program is drawing the low to one side of the pressure trough rather than in the middle like previous runs.

UVM is sure to be stronger this run for a few reasons: sharper trough -- stronger PVA, and stronger frontogenetic forcing with a tighter temp gradient in a stronger deformation zone.

This run would result in a more concentrated band of higher snow totals ... getting on up into the 6-12" range ... *NOT my forecast*

The sharper trough and better PVA almost turns this into a mini-Miller B nuke.

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Mike I think you will do quite well on the 1st system. I am a bit more confident in who will get and where the snow will accumulate. In general AOA 1200 feet areas Catskills, Bergs, Cntl Taconics and Berkshires in the running for 2-4 " lollies 6-8 highest peaks these locations

Yeah--I think it'll be okay. Regardless, any snow in October is a bonus. That being said, the southward shift of the precipitation is giving me pause for MBY. Trying to strike the balance between an earlier start to snow and lowering qpf. Might be a wash for a lot of folks where the snowier areas are dryer and the heavier qpf areas have a waste element due to more rain on the front end.

50.4/33

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Yeah--I think it'll be okay. Regardless, any snow in October is a bonus. That being said, the southward shift of the precipitation is giving me pause for MBY. Trying to strike the balance between an earlier start to snow and lowering qpf. Might be a wash for a lot of folks where the snowier areas are dryer and the heavier qpf areas have a waste element due to more rain on the front end.

50.4/33

I don't want any Oct snow, Isn't that bad juju going into winter?

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The low isn't anymore stretched than other runs. In fact it's a bit more contracted because the s/w is sharper. The only reason people are *perceiving* it to be more stretched is because the program is drawing the low to one side of the pressure trough rather than in the middle like previous runs.

UVM is sure to be stronger this run for a few reasons: sharper trough -- stronger PVA, and stronger frontogenetic forcing with a tighter temp gradient in a stronger deformation zone.

This run would result in a more concentrated band of higher snow totals ... getting on up into the 6-12" range ... *NOT my forecast*

Agree with this. Lows don't really "stretch." Rather, the graphical depictions of surface pressure create this illusion. In this case the area of maximum upper level divergence and surface convergence appears to hang back toward the approaching vortmax in response to it being slightly stronger/more pronounced. This apparently delays the progression of the low center and associated precip without decreasing the intensity.

Meanwhile the thermal boundary has more time to sag southward. This is a wonderfully hypothetical scenario if you are a snow lover. Not so much if you prefer warm, dry Halloweens. I still think you'd be stuck with mostly rain or slop if you're stuck deep in a valley or on the eastern shore.

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The low isn't anymore stretched than other runs. In fact it's a bit more contracted because the s/w is sharper. The only reason people are *perceiving* it to be more stretched is because the program is drawing the low to one side of the pressure trough rather than in the middle like previous runs.

UVM is sure to be stronger this run for a few reasons: sharper trough -- stronger PVA, and stronger frontogenetic forcing with a tighter temp gradient in a stronger deformation zone.

This run would result in a more concentrated band of higher snow totals ... getting on up into the 6-12" range ... *NOT my forecast*

you're reasoning is sound and the NAM will show some crazy UVM but again I look at as I posted..the low is more stretched like a frontal wave or waves (yes, initially there could be two lows); also flow is (fcst) fast and strongly confluent good for more cold air across ENY/CNE but neither great for generating or maintaining (duration of ) any strong UVM if strong UVM occurred at all.

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Can someone remind me the approx. time that models start coming out? It's been about a year now....

you're reasoning is sound and the NAM will show some crazy UVM but again I look at as I posted..the low is more stretched like a frontal wave or waves (yes, initially there could be two lows); also flow is (fcst) fast and strongly confluent good for more cold air across ENY/CNE but neither great for generating or maintaining (duration of ) any strong UVM if strong UVM occurred at all.

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Agree with this. Lows don't really "stretch." Rather, the graphical depictions of surface pressure create this illusion. In this case the area of maximum upper level divergence and surface convergence appears to hang back toward the approaching vortmax in response to it being slightly stronger/more pronounced. This apparently delays the progression of the low center and associated precip without decreasing the intensity.

Meanwhile the thermal boundary has more time to sag southward. This is a wonderfully hypothetical scenario if you are a snow lover. Not so much if you prefer warm, dry Halloweens. I still think you'd be stuck with mostly rain or slop if you're stuck deep in a valley or on the eastern shore.

This NAM solution allows for a decent mid-level circulation to develop too which just enhances the ML frontogenesis to the north...even throwing a bit of extra moisture too via a hint of a CCB. Its definitely the ideal scenario for getting more snow. But until the Euro can come south with that vortmax more, I'm remaining fairly skeptical of anything more than a couple of sloppy inches for anyone.

If there's one piece of legit evidence to hang our hat on for the Euro being too weak/north with the vortmax, its that the Euro does have a bias of hanging back energy in the SW US a little too much...so if more of that vorticity gets engulfed by the main shortwave, then we'd see a deeper solution.

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Two snowstorms in October sounds like a lovely start to the season for me. :D :D :D

This NAM solution allows for a decent mid-level circulation to develop too which just enhances the ML frontogenesis to the north...even throwing a bit of extra moisture too via a hint of a CCB. Its definitely the ideal scenario for getting more snow. But until the Euro can come south with that vortmax more, I'm remaining fairly skeptical of anything more than a couple of sloppy inches for anyone.

If there's one piece of legit evidence to hang our hat on for the Euro being too weak/north with the vortmax, its that the Euro does have a bias of hanging back energy in the SW US a little too much...so if more of that vorticity gets engulfed by the main shortwave, then we'd see a deeper solution.

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Agree with this. Lows don't really "stretch." Rather, the graphical depictions of surface pressure create this illusion. In this case the area of maximum upper level divergence and surface convergence appears to hang back toward the approaching vortmax in response to it being slightly stronger/more pronounced. This apparently delays the progression of the low center and associated precip without decreasing the intensity.

Meanwhile the thermal boundary has more time to sag southward. This is a wonderfully hypothetical scenario if you are a snow lover. Not so much if you prefer warm, dry Halloweens. I still think you'd be stuck with mostly rain or slop if you're stuck deep in a valley or on the eastern shore.

Well lows can be described as stretched, as in a pressure trough. The graphical illusion is in where the surface low is placed and the areal coverage of the first isobar.

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you're reasoning is sound and the NAM will show some crazy UVM but again I look at as I posted..the low is more stretched like a frontal wave or waves (yes, initially there could be two lows); also flow is (fcst) fast and strongly confluent good for more cold air across ENY/CNE but neither great for generating or maintaining (duration of ) any strong UVM if strong UVM occurred at all.

I'm just comparing with previous runs. I agree with everything you said here. The latest run is just a bit more amped up, and shifted toward a more coherent low developing south of New England

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Can someone remind me the approx. time that models start coming out? It's been about a year now....

these aren't exact...but more or less the time I start check on the various models

NAM: 9:45/3:45 (AM/PM)

GFS: 11:30/5:30 (AM/PM)

Canadian/UK/NOGAPS: 12:30ish (AM/PM)

Euro: 2:15 (AM/PM)

keep in mind...these will all shift an hour earlier when DST ends

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