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Historic October NYC Snowstorm Obs/Disco II


Sickman

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Guest Patrick

Wow what a storm...

Here in Clifton, there were large limbs and power lines down just like everywhere else. For some reason, my neighborhood stayed lit. However, friends of ours in Bergen County weren't so lucky. They crashed here with their two young kids, adding to our twins' first snowfall excitement (way too young to appreciate the snow yet, but i'll always be able to tell them about how special they are to have had "their first snowfall before their first halloween, even though they were born in late spring.)" haha.

Now that the mayhem ended, the storm underperformed here from a forecasting perspective. I may not have been able to measure correctly this time, with the chaos in the house, but I think I eeked out 4 inches. An overperformer by any standard, but not anywhere near the high totals forecasted. The compaction rate was undoubtedly responsible, but I also didn't experience the late night crazy snow band that was so common in every storm last winter.

I still can't believe it. I just can't believe it.

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I just measured 7 inches. Difficult to find a spot that wasn't corrupted though, so take it FWIW.

It'll be a White Halloween though!

'White Halloween' I think best captures the unusual nature of this event. Some other things I never thought I'd say or see:

1. Talking about an October sun angle with respect to a snow storm when it is actually October and not February or March.

2. Not being able to see the snow by the streetlight because of all the deciduous green leaves.

3. Worrying in October that I might have waited too long to winterize the sprinkler system.

Given the fact that we're not in Canada or the Arctic, it's interesting that we've seen noteworthy snow now in October, November, December, January, February, March, and April around here.

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Im not sure about the official 17.2" measurement in Danbury......

Wet snow like this compacts so much and so fast, that what's on the ground the next day might not look much like what actually fell. Plus, the warm ground melts some of it from below (plus 40s for today's high under full sun). Even after a few hours, the snow noticeably compacts, and melts from beneath.

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Wet snow like this compacts so much and so fast, that what's on the ground the next day might not look much like what actually fell. Plus, the warm ground melts some of it from below (plus 40s for today's high under full sun). Even after a few hours, the snow noticeably compacts, and melts from beneath.

yea i understand all that....but i didnt just wake up, im responding now because I just saw the final report and it shocked me. i was out yesterday around town before 5pm and there was about 6". the spotter registed something like 7.2" at 5:50pm i believe. I was home watching the storm for the rest of the night. at 10pm I think, it us up to 13.2" which Quincy (Met from danbury), suspected was too high already. that means he measured another 4" after that.....and the accumulating snow ended around midnight.

is it possible? sure...i didnt measure and the skywarn spotter did. but the 17.2" doesnt really measure up well with totals from nearby areas. Bethel, neighboring just to the SE, 3 miles apart center to center, recorded 11.5". Close to a 6" difference this close is alot. It justifies questioning the validity of the measurements, i think.

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solid +SN with HUGE flakes, at least 1 inch in diameter. 11.0 inches storm total (may be slightly higher due to compaction)

saw two flashes of lightning in a two minute time span

it snowed under that band for another 45mins....so being generous, that would bring it close to 12". factor in compaction......

Unless the 17.2" measurement was in the NW portion of town up in the hills, Quincy is east side.....so Hopefully he can chime in soon.

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For those who were wondering why the CCB didn't seem to fill out as much, the answer lies within the mid levels. The H7 low was forecast to close off over Southeast PA, or the NJ Coast and then shift eastward Southeast of Long Island on most models. This is integral in helping develop the classic deform in the cold conveyor belt---remember the classic images from December 26 of last year, where the H7 low was closed off tightly off the NJ Coast.

This feature took longer to develop and strengthen than modeled--which likely also attributed to the ~700mb warm layer which was noted on a sounding posted during the storm itself. The delay in this feature's maturation likely contributed to both things; the warm layer, and the slightly less-than-ideal CCB.

Here are two images from the storm system which are archived RUC initialization's from as the event was occurring. The first image, below, shows the H7 low still open (bottom left). At this time, the surface low and h5/h8 setups are in a prime position to produce ccb/deformation/etc if the H7 low was developed...but it was not.

http://i.imgur.com/GA2UH.gif

In this second image, from 00z Sunday (around 8pm Saturday evening), you can see that the H7 low has closed off. Not surprisingly, near this time (possibly slightly before it since the image is in 6 hour increments)...a very large deformation band developed, with significant subsidence around it...the band developing to the northwest of the closed h7 low which is rather classic. Prior to this, the deformation was having trouble becoming more "classically" organized....there were numerous fluctuations in intensity and position.

http://i.imgur.com/62rOz.gif

Obviously nobody is complaining...but it's interesting in retrospect. Watching this event unfold definitely magnified the importance of the 700mb low and the mid level centers in the development of deformation bands and dynamics. Just the slight delay in it's development caused significant forecast impacts.

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For those who were wondering why the CCB didn't seem to fill out as much, the answer lies within the mid levels. The H7 low was forecast to close off over Southeast PA, or the NJ Coast and then shift eastward Southeast of Long Island on most models. This is integral in helping develop the classic deform in the cold conveyor belt---remember the classic images from December 26 of last year, where the H7 low was closed off tightly off the NJ Coast.

This feature took longer to develop and strengthen than modeled--which likely also attributed to the ~700mb warm layer which was noted on a sounding posted during the storm itself. The delay in this feature's maturation likely contributed to both things; the warm layer, and the slightly less-than-ideal CCB.

Here are two images from the storm system which are archived RUC initialization's from as the event was occurring. The first image, below, shows the H7 low still open (bottom left). At this time, the surface low and h5/h8 setups are in a prime position to produce ccb/deformation/etc if the H7 low was developed...but it was not.

http://i.imgur.com/GA2UH.gif

In this second image, from 00z Sunday (around 8pm Saturday evening), you can see that the H7 low has closed off. Not surprisingly, near this time (possibly slightly before it since the image is in 6 hour increments)...a very large deformation band developed, with significant subsidence around it...the band developing to the northwest of the closed h7 low which is rather classic. Prior to this, the deformation was having trouble becoming more "classically" organized....there were numerous fluctuations in intensity and position.

http://i.imgur.com/62rOz.gif

Obviously nobody is complaining...but it's interesting in retrospect. Watching this event unfold definitely magnified the importance of the 700mb low and the mid level centers in the development of deformation bands and dynamics. Just the slight delay in it's development caused significant forecast impacts.

That being said, the northern end of the band from Wrn Mass to Maine was perfectly healthy and dumping 20+ amounts. It was only the southern end that suffered from the slower deepening at the low and mid levels.

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But keep in mind QPF amounts were in the 1.5 to 2" range. So had it all fallen as snow and been cold enough we all would have been digging out of 18"+ amounts

That being said, the northern end of the band from Wrn Mass to Maine was perfectly healthy and dumping 20+ amounts. It was only the southern end that suffered from the slower deepening at the low and mid levels.

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The city got 2" of precipitation. Would have been 20 to 30" of snow if it was a few degrees colder and all snow...CCB, dryslot or not

I wonder how much snow NYC would have received if the ccb band panned out and the dry slot did not make it into the city. This storm reminded me of the Jan 2008 storm where the city was supposed to get a lot of snow and only received rain and a little snow .

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My town smells like fresh cut wood everywhere...kind of weird. Once this fog clears ill try to take more pictures, but i have yet to find an area around here where thee isnt significant tree and power damage.

Same here, and we got significant less than you (I think?). Campus is still littered with downed trees and branches 2 days later, and the fire department was on my street this morning for a second time clearing downed powerlines.

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Yeah it sounds like most places actually fared worse than with Irene. Even healthy limbs were brought down due to the weight of the snow even without the excessive winds.

.

Same here, and we got significant less than you (I think?). Campus is still littered with downed trees and branches 2 days later, and the fire department was on my street this morning for a second time clearing downed powerlines.

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This must be close to some kind of record for the earliest end to the growing season in the NYC/L.I. area:

PUBLIC INFORMATION STATEMENT

NATIONAL WEATHER SERVICE NEW YORK NY

1017 AM EDT MON OCT 31 2011

...END OF THE GROWING SEASON FOR ENTIRE REGION...

THE WIDESPREAD SUB-FREEZING TEMPERATURES LAST NIGHT AND THE

WEEKEND WINTER STORM HAVE BROUGHT THE GROWING SEASON TO AN END

ACROSS ALL ZONES IN NORTHEASTERN NEW JERSEY...THE LOWER HUDSON

VALLEY...NEW YORK CITY AND LONG ISLAND. THERE WILL BE NO FURTHER

FROST OR FREEZE PRODUCTS ISSUED FOR THE AREA THIS SEASON.

THE FROST/FREEZE PROGRAM WILL BEGIN AGAIN IN 2012 STARTING WITH

THE CLIMATOLOGICAL DATES FOR THE AVERAGE LAST FREEZE IN THE SPRING.

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This must be close to some kind of record for the earliest end to the growing season in the NYC/L.I. area:

PUBLIC INFORMATION STATEMENT

NATIONAL WEATHER SERVICE NEW YORK NY

1017 AM EDT MON OCT 31 2011

...END OF THE GROWING SEASON FOR ENTIRE REGION...

THE WIDESPREAD SUB-FREEZING TEMPERATURES LAST NIGHT AND THE

WEEKEND WINTER STORM HAVE BROUGHT THE GROWING SEASON TO AN END

ACROSS ALL ZONES IN NORTHEASTERN NEW JERSEY...THE LOWER HUDSON

VALLEY...NEW YORK CITY AND LONG ISLAND. THERE WILL BE NO FURTHER

FROST OR FREEZE PRODUCTS ISSUED FOR THE AREA THIS SEASON.

THE FROST/FREEZE PROGRAM WILL BEGIN AGAIN IN 2012 STARTING WITH

THE CLIMATOLOGICAL DATES FOR THE AVERAGE LAST FREEZE IN THE SPRING.

post-519-0-09433500-1320073295.png

post-519-0-01891900-1320073288.png

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The city got 2" of precipitation. Would have been 20 to 30" of snow if it was a few degrees colder and all snow...CCB, dryslot or not

If that indeed happened, the damage would have been absolutely mayhem. Far worse than any Hurricane.

On this note, the damage over my area is a little bit worse than Irene... Tons of trees down.

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Quick question re the end of the growing season.. Why does it make a difference when this occurs.. For example it may be weeks before NYC reaches 32 again.. If it got warmer things couldn't technically go anymore? Say for example this happened in mid sept.. (a freak frost). Would that mean the growing season would be over?

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I suppose anything that survived the frost/freeze could grow again. It's not like the ground is frozen and we likely won't have another one along the coast for weeks. Usually even just a little bit of frost is enough to kill sensitive vegetation (ironically the snow alone with temps above freezing didn't seem to hurt most of my remaining flowers). The temps in the 20s this morning did them in though.

Quick question re the end of the growing season.. Why does it make a difference when this occurs.. For example it may be weeks before NYC reaches 32 again.. If it got warmer things couldn't technically go anymore? Say for example this happened in mid sept.. (a freak frost). Would that mean the growing season would be over?

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Good synoptic explanation, Thanks.

What occurred was quite the opposite of the initial forecast - we had snow develop soon after the precipitation onset, changing to a mix before ending. I'm shocked we didn't lose power in Garwood. Probably very luck the revised forecast did not pan out. Tree limbs and branches breaking simultaneously around 1:45 PM Saturday.

For those who were wondering why the CCB didn't seem to fill out as much, the answer lies within the mid levels. The H7 low was forecast to close off over Southeast PA, or the NJ Coast and then shift eastward Southeast of Long Island on most models. This is integral in helping develop the classic deform in the cold conveyor belt---remember the classic images from December 26 of last year, where the H7 low was closed off tightly off the NJ Coast.

This feature took longer to develop and strengthen than modeled--which likely also attributed to the ~700mb warm layer which was noted on a sounding posted during the storm itself. The delay in this feature's maturation likely contributed to both things; the warm layer, and the slightly less-than-ideal CCB.

Here are two images from the storm system which are archived RUC initialization's from as the event was occurring. The first image, below, shows the H7 low still open (bottom left). At this time, the surface low and h5/h8 setups are in a prime position to produce ccb/deformation/etc if the H7 low was developed...but it was not.

http://i.imgur.com/GA2UH.gif

In this second image, from 00z Sunday (around 8pm Saturday evening), you can see that the H7 low has closed off. Not surprisingly, near this time (possibly slightly before it since the image is in 6 hour increments)...a very large deformation band developed, with significant subsidence around it...the band developing to the northwest of the closed h7 low which is rather classic. Prior to this, the deformation was having trouble becoming more "classically" organized....there were numerous fluctuations in intensity and position.

http://i.imgur.com/62rOz.gif

Obviously nobody is complaining...but it's interesting in retrospect. Watching this event unfold definitely magnified the importance of the 700mb low and the mid level centers in the development of deformation bands and dynamics. Just the slight delay in it's development caused significant forecast impacts.

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Good synoptic explanation, Thanks.

What occurred was quite the opposite of the initial forecast - we had snow develop soon after the precipitation onset, changing to a mix before ending. I'm shocked we didn't lose power in Garwood. Probably very luck the revised forecast did not pan out. Tree limbs and branches breaking simultaneously around 1:45 PM Saturday.

New addition to the Union County crew?

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