Re: Observations/ Final Discussion Thread 1/2 - 1/3, 2014 Snowstorm

[skinsfan1177]

Where is Frank?

[RJB8525]

We got good action here in S.I quick good coating + a little more all of a sudden within a half hour it just started then it got real heavy

[SNOW MAN]

Light snow in Whiting NJ. Not sticking to the roads yet only the grass and colder surfaces.

[cooladi]

Snow has started in Franklin Square at around 6:30. Still light, but sticking. Based on my advice that tomorrow morning will be extremely difficult travelling, boss has booked a hotel in NYC in order to make his critical, must attend meeting. Please let it snow, let it snow, let it snow!

[Quietace]

Where is Frank?

Work

[bloc1357]

Where is Frank?

Working until 9...I think he said

[SNOW MAN]

Ace I'm staying at Moms in Whiting NJ for the holidays, it's close to Toms River. What's your call for snow totals in this area?

[Quietace]

Ace I'm staying at Moms in Whiting NJ for the holidays, it's close to Toms River. What's your call for snow totals in this area?

6-8

[SNOW MAN]

Thanks !

[jmanley32]

Well I guess the warnings are pretty set in stone, no blizzard warnings for anywhere other than LI, seems odd but ok. Excuse me also parts of MA but not tristate area.

[docstox12]

Coming up on 1/2 inch.Light to moderate snow.Mahwah NJ

[Fededle22]

Coating on the ground and snowing. 20 degrees.

[Grselig]

Moderate snow in Wayne. Was 19 degree an hour ago. Mugs you have the right idea. You are the Man!! Snow too dry to build snowman with the kids. If we can this would be their first.

[Quietace]

500mb looks good. Moving from neutral over the last hour...
http://www.spc.noaa.gov/exper/mesoanalysis/s19/500mb/500mb.gif?1388708552645

[amugs]

500mb looks good. Moving from neutral over the last hour...
http://www.spc.noaa.gov/exper/mesoanalysis/s19/500mb/500mb.gif?1388708552645

Tilt Negative you beast and then explode!!

[Quietace]

From Epawa again
The dry slot seen on the radar image below will not advance much. The reasoning is because our primary low is jumping over to the coast (NC). This is temporarily allowing the precip shield to collapse to the east. As this low intensifies and moves northward it will allow the radar returns to advance more north and west. This goes back to the "negative tilted trough" explanation in last post. When the trough goes negative it leads to rapidly rising air downstream. In this case, it would be over our region and the developing low. This creates a stronger low that will not be able to escape to the east and greater lifting for heavier snow.

https://scontent-a-lga.xx.fbcdn.net/hphotos-ash3/1477586_444713808962898_3881831_n.png

[Quietace]

500mb looks good. Moving from neutral over the last hour...
http://www.spc.noaa.gov/exper/mesoanalysis/s19/500mb/500mb.gif?1388708552645

Tilt Negative you beast and then explode!!

The HRRR is starting to catch on to this. Has been increasing QPF each run. Almost 1 inch for JS and LI. Widspread .75

[aiannone]

Low seems to have phased much earlier. We are in for one hell of a storm!

[docstox12]

500mb looks good. Moving from neutral over the last hour...
http://www.spc.noaa.gov/exper/mesoanalysis/s19/500mb/500mb.gif?1388708552645

Tilt Negative you beast and then explode!!

The HRRR is starting to catch on to this. Has been increasing QPF each run. Almost 1 inch for JS and LI. Widspread .75

There's your widespread one foot at these temps.We'll see overnight how it pans out, but this is good news.

[Quietace]

Toms River up to Sandy Hook see 8-9" on HRRR w/ 10:1. 6+ spreads inland. Think Li should have more though.

[devsman]

Here in Merrick LI. Light to mod snow. 1/4 on grass but not sticking to street. Winds picking up.

[skinsfan1177]

Ratios will get to 15:1 at some point.

[Noreaster]

From a poster at americanwx regarding ratios..its good info and stuff some of us know but he put it pretty simply which is helpful.

"A few folks have asked about snow ratios and what affects snow ratios.  I'm not a meteorologist, but I am an expert in nucleation/crystallization phase changes (in the chemical/pharmaceutical industry, but the concepts apply almost exactly to snow). 


So, for those who are curious why our snow ratios will be so high (15-20:1, which means 0.5" of liquid gives 7.5-10" of snow, instead of the usual 5" of snow in a typical 10:1 ratio), conditions are expected to be very favorable for large, dry, fluffy snow crystals in the primary snow growth region (around 700 mb of pressure, several thousand feet up in the atmosphere).  Hope what follows helps. 


 


Specifically, as relatively warm, moist air saturated with water vapor is lifted into the 700 mb region, which will be very cold, relatively speaking vs. "typical" snowstorms, i.e., temps will be about -10 to -22C at that level, this will lead to that water vapor becoming highly superaturated, meaning the relative humidity of that parcel of air at that temperature actually well exceeds 100%, which denotes being supersaturated, i.e., beyond 100% saturation; thermodynamically, this situation cannot exist for long, as that supersaturated vapor wants to either condense into liquid or directly condense into frozen particles, depending on the temp (and pressure). 


 


This supersaturation leads to very fast snow crystal nucleation (the creation of snow crystals at those cold temps aloft), followed by good dendritic snow growth (via vapor phase deposition - the water vapor that remains supersaturated in the parcel essentially changes phases from vapor to ice, as it crystallizes and grows directly on the "starter crystals" that just nucleated) on those crystals, leading to dendrites and plates.  These dendtrites and plates "layer" better on the ground, such that there is more air present in the snow on the ground, resulting in a lower bulk density (low mass per unit volume) of that snow or a greater snow depth to liquid equivalent ratio.  Think of a pile of dry leaves vs. a pile of wet, aged leaves, in which the dry leaves contain ar less leaves and far more air per unit volume vs. wet leaves. 


 


To get powdery, fluffy, low bulk density snow, one needs both conditions, though: cold temps in the snow growth region, plus good vertical lift to drive the supersaturation - it's the vertical lift which carries warm, relatively moist air from the surface (or near the surface) up into the primary snow growth region around 700 mb (to be sure, supersaturation and nucleation/crystallization occur at more heights than 700 mb - it's just that the 700 mb region is the "standard" referred to), which leads to the supersaturation and at the right temps, the good plates/dendrites form and grow.  See the link for the pics of the crystals one typically gets at various temps in the snow growth region. 


 


Why -10 to -22C in the snow growth layer leads to plates and dendrites vs. rods or cubes is unclear to me.  Perhaps that's something I should look into..."


 


http://stream2.cma.gov.cn/pub/comet/MountainMeteorology/SnowpackandItsAssessment/comet/afwa/snowpack/media/graphics/habits.jpg

[amugs]

Ratios will get to 15:1 at some point.

skins we r there up here as we speak at18* woohoooo   

Bring on the foot plus Hercules - greedy I know lol.

[amugs]

From a poster at americanwx regarding ratios..its good info and stuff some of us know but he put it pretty simply which is helpful.

"A few folks have asked about snow ratios and what affects snow ratios.  I'm not a meteorologist, but I am an expert in nucleation/crystallization phase changes (in the chemical/pharmaceutical industry, but the concepts apply almost exactly to snow). 


So, for those who are curious why our snow ratios will be so high (15-20:1, which means 0.5" of liquid gives 7.5-10" of snow, instead of the usual 5" of snow in a typical 10:1 ratio), conditions are expected to be very favorable for large, dry, fluffy snow crystals in the primary snow growth region (around 700 mb of pressure, several thousand feet up in the atmosphere).  Hope what follows helps. 

That is great info . Nor you post or follow that board?
 


Specifically, as relatively warm, moist air saturated with water vapor is lifted into the 700 mb region, which will be very cold, relatively speaking vs. "typical" snowstorms, i.e., temps will be about -10 to -22C at that level, this will lead to that water vapor becoming highly superaturated, meaning the relative humidity of that parcel of air at that temperature actually well exceeds 100%, which denotes being supersaturated, i.e., beyond 100% saturation; thermodynamically, this situation cannot exist for long, as that supersaturated vapor wants to either condense into liquid or directly condense into frozen particles, depending on the temp (and pressure). 


 


This supersaturation leads to very fast snow crystal nucleation (the creation of snow crystals at those cold temps aloft), followed by good dendritic snow growth (via vapor phase deposition - the water vapor that remains supersaturated in the parcel essentially changes phases from vapor to ice, as it crystallizes and grows directly on the "starter crystals" that just nucleated) on those crystals, leading to dendrites and plates.  These dendtrites and plates "layer" better on the ground, such that there is more air present in the snow on the ground, resulting in a lower bulk density (low mass per unit volume) of that snow or a greater snow depth to liquid equivalent ratio.  Think of a pile of dry leaves vs. a pile of wet, aged leaves, in which the dry leaves contain ar less leaves and far more air per unit volume vs. wet leaves. 


 


To get powdery, fluffy, low bulk density snow, one needs both conditions, though: cold temps in the snow growth region, plus good vertical lift to drive the supersaturation - it's the vertical lift which carries warm, relatively moist air from the surface (or near the surface) up into the primary snow growth region around 700 mb (to be sure, supersaturation and nucleation/crystallization occur at more heights than 700 mb - it's just that the 700 mb region is the "standard" referred to), which leads to the supersaturation and at the right temps, the good plates/dendrites form and grow.  See the link for the pics of the crystals one typically gets at various temps in the snow growth region. 


 


Why -10 to -22C in the snow growth layer leads to plates and dendrites vs. rods or cubes is unclear to me.  Perhaps that's something I should look into..."


 


http://stream2.cma.gov.cn/pub/comet/MountainMeteorology/SnowpackandItsAssessment/comet/afwa/snowpack/media/graphics/habits.jpg

[deadrabbit79]

Snowing pretty good here in White Plains with temp around 20., whatever the outcome is with regards to snow totals its been a fun week on this board. Thanks to everyone for their insight. And special thanks to Frank and all the other pros on here, i trust you guys more than the locals on TV.

[snowday111]

18* and light to moderate snow over here in Hillsdale, NENJ - waiting for the NO SCHOOL phone call in the next 1/2 hr or so...

Going to make some TollHouse Cookies, Hot Chocolate with some homemade Bailey's, sit by my fire, watch the snow fall and then cap it off with a glass of port wine - priceless.

Just got my call from my district. My kids district will be closed as well. Some districts are waiting until 8:00 to send out a call.

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