Major Nor'easter snow storm (possible top 20) Noon Wednesday-Noon Thursday Dec 16-17, 2020

[jdj5211]

just looking at the 18z run compared to the 12z run...as mentioned it looks like it's trying to close the low off but just misses.  I'm curious as to why it's starting to pick that idea back up now?  IF it was able to close off and that's a big IF...that transfer would need to happen further to the SW if we want this thing to slow to a crawl without impeading our track and snowfall totals....wherever that CCB were to set up would have the potential for 24+ with that scenario....  thoughts?

[wdrag]

I've been out of the forum for 7 hours and coming back to the still south GFS op is a little disconcerting but as many have posted... basically other models north and 12+. Maybe it's somewhere in between...blend and shift south 30 miles?  Just can't add anything useful beyond this.  By the way, I hope we all have something to post on the Monday thread.  It's looking pretty good to me for a swath of wet snow.  Will try and update both threads,  Monday around 630A.  

PHI---bold and I think a very smart Watch move.  We don't often get 1-2 footers... and even if some of the watch fails,  it's a watch.  The idea is get public attention with official product and steady the uncertainty a bit. There are multiple facets to this storm... damaging wind and wet snow accumulation with potential for considerable power outages LI and just se of I95, along with moderate coastal flood threat Thursday morning,  airline impact and basic travel impacts are potentially very high I95 corridor on up through at least the I84 corridor, and probably up to near I90.  Have a good night.  

[Allsnow]

[sussexcountyobs]

43 minutes ago, Stormlover74 said:

Some of my faves are the heavy wet storms with big flakes that pile up quickly and stick to everything 

2-10-10 I believe had blizzard warnings up but we got no wind and it was 32 to 33 the whole time. I got 14" in about 8 hours

That's what I'm  talking about.

[wdrag]

30 minutes ago, jdj5211 said:

just looking at the 18z run compared to the 12z run...as mentioned it looks like it's trying to close the low off but just misses.  I'm curious as to why it's starting to pick that idea back up now?  IF it was able to close off and that's a big IF...that transfer would need to happen further to the SW if we want this thing to slow to a crawl without impeading our track and snowfall totals....wherever that CCB were to set up would have the potential for 24+ with that scenario....  thoughts?

Closing would help but maybe toss too much warming up to I80 to shave amounts by 6+ inches due to rain-sleet.  

SST's are a bit of above normal so lapse rates will be enhanced slightly.  It seems to me this storm maxes intensity along the s NJ coast Thursday morning and then occludes east or east northeast, with a subsequent weakening of the short wave.   This one is digging far enough south into the southern states before turning northeast  that it's yanking moisture newd aloft, and the big high in Quebec adds an easterly low level jet flow and lift over the ene-wsw oriented thickness to yield the qpf modeled.  I'm good without a stall... this will be very big and may satisfy the daily record snowfall at CP by midnight Wednesday night? (front end thump). Virtually no chance of exceeding the Thursday daily record of 2003 -19.8

 

[HVSnowLover]

12 minutes ago, Allsnow said:

Does that shift east in future frames?

[ZNSTATED]

Any thoughts on the potential for thunder snow with this storm. Seems like this storm would have the dynamics to create it

[jdj5211]

Just now, HVSnowLover said:

Does that shift east in future frames?

If we can shift those 2" QPF totals east about 100 miles....that would put NENJ/NYC in the 18-24" bullseye!  (what I'm selfishly hoping for here in NE NJ)

[SnoSki14]

Hopefully this will give my area a nice 6" snowfall.

That's all I ask.

[MJO812]

[shadowsintherain]

2 minutes ago, MJO812 said:

These panes show 2.00" potential liquid total for a LOT of the subforum. Wow. 

[ARyan]

11 hours ago, bluewave said:

The models that handle the 500 mb heights near Oregon and general PNA best will get the storm track correct. 
 

Bottom line: I'll be really curious to see tonight's MFR sounding. That 500mb height observation will perhaps help give us (and models) a clue where the storm might go later on. 5570m vs 5590m may seem small, but in a nonlinear system those tiny differences grow rapidly!

 

Following up this. Based on this post and the 0z MFR sounding, it would hint at a further NW track...

[HVSnowLover]

21 minutes ago, jdj5211 said:

If we can shift those 2" QPF totals east about 100 miles....that would put NENJ/NYC in the 18-24" bullseye!  (what I'm selfishly hoping for here in NE NJ)

Looking at the frames just posted I think NYC/NE NJ would be at or close to 2" qpf on that run.  

[Barman49]

Looking at the frames just posted I think NYC/NE NJ would be at or close to 2" qpf on that run.  

Those look like hourly snowfall rates for that frame not total qpf. I would think the next frame shifts east into eastern NJ & NYC.

Sent from my IN2017 using Tapatalk

[cleetussnow]

1 hour ago, MJO812 said:

With the CCB band over NYC

Insane run

Mother of God.

[Isotherm]

I also posted the following in my winter outlook thread:

Brief update with some thoughts on the storm threat & overall winter outlook. The provenance of this week's storm threat for the Northeast corridor can be traced backward in time to the robust poleward and eastward transfer of angular momentum, which is large part mediated this fairly unique (given various background indicators) episode of high latitude blocking. Most of the diminution of negativity is focused in the AO domain space, but the NAO has turned negative and will remain there for a period. It is this poleward momentum deposit and associated +GP height/50-50 anomaly which will act to largely countermand a less than optimal Pacific regime. 

This projected storm represents the most auspicious precondition set-up in a few years for the Northeast coast. It is highly likely that Baltimore, Philadelphia, Boston and NYC will receive at least 5-6" of snowfall, possibly DCA as well. The heaviest axis of snow - location indeterminate - will likely feature 8-16" on average. The most accumulation will occur approximately 1.5 degrees W/N of the path of the z850 low, and slightly W/N of the path of the z700 low, as evidenced by optimal uplift/DGZ confluence. This zone may occur anywhere from the northern mid Atlantic coast to north of NYC, depending upon the z500 evolution. It's nigh impossible to ascertain this zone right now.

 However, more importantly, from my perspective, is the storm opportunity provides a quasi-indicator for forthcoming pattern relapses.

December's temperature departures thus far are according with my winter outlook: generally warm nationwide with the core of the warmth in the W-C plains, and cooler in the SE US. The z500 of +EPO, neutral-positive PNA is also verifying. The December AO and potentially NAO will be more negative than expected (hence the larger storm threat this week). However, this episode provides insight to me, that tropospheric receptivity is heightened for another pulse(s) of momentum transfer, and increased favorability, for my target winter month in the Northeast (January). If anything, the events of this week suggest to me that my January ideas are on track (for NYC: slightly colder than normal, and snowier than normal). A technical SSW is unlikely this winter, but the SPV should be weaker than normal for early-mid January.

My expectation is the NAO will neutralize beyond this week, along with the AO, as the SPV reconsolidates and momentum alters. Thereupon, the Pacific should reorganize into a more conducive structure again, by the end of December. Thereafter, there will be another decline opportunity in the NAO/AO in the month of January, potentially operating contemporaneously with a +PNA and even near neutral EPO. My thoughts remain the same for beyond January. However, this week's storm will increase the probability that NYC's seasonal snowfall ends in the upper portion of my range, assuming the winter pattern continues to proceed as I anticipate.

My projection at this stage for snowfall this week is 6-12" for NYC, a significant snowstorm. Again, the heaviest axis will be a function of z700/z850 proximities.

[friedmators]

[uncle W]

38 minutes ago, wdrag said:

Closing would help but maybe toss too much warming up to I80 to shave amounts by 6+ inches due to rain-sleet.  

SST's are a bit of above normal so lapse rates will be enhanced slightly.  It seems to me this storm maxes intensity along the s NJ coast Thursday morning and then occludes east or east northeast, with a subsequent weakening of the short wave.   This one is digging far enough south into the southern states before turning northeast  that it's yanking moisture newd aloft, and the big high in Quebec adds an easterly low level jet flow and lift over the ene-wsw oriented thickness to yield the qpf modeled.  I'm good without a stall... this will be very big and may satisfy the daily record snowfall at CP by midnight Wednesday night? (front end thump). Virtually no chance of exceeding the Thursday daily record of 2003 -19.8

 

for the record 2003 was 5.8" in Central Park...

[friedmators]

I wanna see the Kuchera for Ensemble #1 of the 18z Euro.  I bet its close to 4 feet for NNJ.

[Sn0waddict]

5 minutes ago, friedmators said:

That’s with snow still falling for most of the area correct?

[clskinsfan]

I dont want to hijack your thread but do one of you have a bookmark saved for the storm map thread you used to have here? I want to bookmark it to my new computer. Thanks!

NVM all. I found it. I hope you all get crushed up here!

[friedmators]

Just now, Sn0waddict said:

That’s with snow still falling for most of the area correct?

Indeed @ 90.

[uncle W]

NYC 12/16

..snowfall...................max depth...

.....7.0" in 1896..........10" in 1960
.....1.7" in 1973............9" in 1916
.....1.0" in 2008............8" in 1917
.....0.7" in 1925............7" in 1896
.....0.6" in 1950............6" in 1904

Philadelphia 12/16

....snowfall......

.....7.1" in 1896

.....3.5" in 1973

.....2.0" in 1981

................................................................................

NYC 12/17

....snowfall.....est. max snow depth...
....6.7" in 1932..........9" in 1904
....3.0" in 1904..........8" in 1960
....2.8" in 2016..........8" in 1917
....1.8" in 1919..........7" in 1916
....1.5" in 2013 .........7" in 1932

Philadelphia 12/17

...snowfall......

.....7.3" in 1932

.....2.5" in 1904

.....1.3" in 1901

[wdrag]

7 minutes ago, uncle W said:

for the record 2003 was 5.8" in Central Park...

 

1 minute ago, Sn0waddict said:

That’s with snow still falling for most of the area correct?

My terrible mistake!  I was reading mo to date.  Here's what I have for the 17th.  Can this work?    Just let me know.  MY ERROR on the 19.8. Great catch!!

Hmmmm... small chance we could break two successive daily records. 

Almanac for New York-Central Park Area, NY (ThreadEx)
December 17, 2020

Daily Data	Observed	Normal	Record Highest	Record Lowest
Max Temperature	M	42	62 in 2000	15 in 1876
Min Temperature	M	32	50 in 2015	1 in 1919
Avg Temperature	M	36.9	54.5 in 2015	10.5 in 1876
Precipitation	M	0.13	2.28 in 1888	0.00 in 2017
Snowfall	M	0.1	6.7 in 1932	0.0 in 2019

[Nibor]

8 minutes ago, Isotherm said:

I also posted the following in my winter outlook thread:

Brief update with some thoughts on the storm threat & overall winter outlook. The provenance of this week's storm threat for the Northeast corridor can be traced backward in time to the robust poleward and eastward transfer of angular momentum, which is large part mediated this fairly unique (given various background indicators) episode of high latitude blocking. Most of the diminution of negativity is focused in the AO domain space, but the NAO has turned negative and will remain there for a period. It is this poleward momentum deposit and associated +GP height/50-50 anomaly which will act to largely countermand a less than optimal Pacific regime. 

This projected storm represents the most auspicious precondition set-up in a few years for the Northeast coast. It is highly likely that Baltimore, Philadelphia, Boston and NYC will receive at least 5-6" of snowfall, possibly DCA as well. The heaviest axis of snow - location indeterminate - will likely feature 8-16" on average. The most accumulation will occur approximately 1.5 degrees W/N of the path of the z850 low, and slightly W/N of the path of the z700 low, as evidenced by optimal uplift/DGZ confluence. This zone may occur anywhere from the northern mid Atlantic coast to north of NYC, depending upon the z500 evolution. It's nigh impossible to ascertain this zone right now.

 However, more importantly, from my perspective, is the storm opportunity provides a quasi-indicator for forthcoming pattern relapses.

December's temperature departures thus far are according with my winter outlook: generally warm nationwide with the core of the warmth in the W-C plains, and cooler in the SE US. The z500 of +EPO, neutral-positive PNA is also verifying. The December AO and potentially NAO will be more negative than expected (hence the larger storm threat this week). However, this episode provides insight to me, that tropospheric receptivity is heightened for another pulse(s) of momentum transfer, and increased favorability, for my target winter month in the Northeast (January). If anything, the events of this week suggest to me that my January ideas are on track (for NYC: slightly colder than normal, and snowier than normal). A technical SSW is unlikely this winter, but the SPV should be weaker than normal for early-mid January.

My expectation is the NAO will neutralize beyond this week, along with the AO, as the SPV reconsolidates and momentum alters. Thereupon, the Pacific should reorganize into a more conducive structure again, by the end of December. Thereafter, there will be another decline opportunity in the NAO/AO in the month of January, potentially operating contemporaneously with a +PNA and even near neutral EPO. My thoughts remain the same for beyond January. However, this week's storm will increase the probability that NYC's seasonal snowfall ends in the upper portion of my range, assuming the winter pattern continues to proceed as I anticipate.

My projection at this stage for snowfall this week is 6-12" for NYC, a significant snowstorm. Again, the heaviest axis will be a function of z700/z850 proximities.

Awesome post. Hope you're right about January.

[uncle W]

3 minutes ago, wdrag said:

 

My terrible mistake!  I was reading mo to date.  Here's what I have for the 17th.  Can this work?    Just let me know.  MY ERROR on the 19.8. Great catch!!

Hmmmm... small chance we could break two successive daily records. 

Almanac for New York-Central Park Area, NY (ThreadEx)
December 17, 2020

Daily Data	Observed	Normal	Record Highest	Record Lowest
Max Temperature	M	42	62 in 2000	15 in 1876
Min Temperature	M	32	50 in 2015	1 in 1919
Avg Temperature	M	36.9	54.5 in 2015	10.5 in 1876
Precipitation	M	0.13	2.28 in 1888	0.00 in 2017
Snowfall	M	0.1	6.7 in 1932	0.0 in 2019

1932-33 was a very mild winter especially in January...it did get a 7" storm on the 17th but very little after that until February...February had a 10" storm...seasonal snowfall was near average...

the 1932 storm from the Brooklyn Eagle...

http://bklyn.newspapers.com/image/59970904/

http://bklyn.newspapers.com/image/59970913

http://bklyn.newspapers.com/image/59971128/

http://bklyn.newspapers.com/image/59971138

[jm1220]

24 minutes ago, Isotherm said:

I also posted the following in my winter outlook thread:

Brief update with some thoughts on the storm threat & overall winter outlook. The provenance of this week's storm threat for the Northeast corridor can be traced backward in time to the robust poleward and eastward transfer of angular momentum, which is large part mediated this fairly unique (given various background indicators) episode of high latitude blocking. Most of the diminution of negativity is focused in the AO domain space, but the NAO has turned negative and will remain there for a period. It is this poleward momentum deposit and associated +GP height/50-50 anomaly which will act to largely countermand a less than optimal Pacific regime. 

This projected storm represents the most auspicious precondition set-up in a few years for the Northeast coast. It is highly likely that Baltimore, Philadelphia, Boston and NYC will receive at least 5-6" of snowfall, possibly DCA as well. The heaviest axis of snow - location indeterminate - will likely feature 8-16" on average. The most accumulation will occur approximately 1.5 degrees W/N of the path of the z850 low, and slightly W/N of the path of the z700 low, as evidenced by optimal uplift/DGZ confluence. This zone may occur anywhere from the northern mid Atlantic coast to north of NYC, depending upon the z500 evolution. It's nigh impossible to ascertain this zone right now.

 However, more importantly, from my perspective, is the storm opportunity provides a quasi-indicator for forthcoming pattern relapses.

December's temperature departures thus far are according with my winter outlook: generally warm nationwide with the core of the warmth in the W-C plains, and cooler in the SE US. The z500 of +EPO, neutral-positive PNA is also verifying. The December AO and potentially NAO will be more negative than expected (hence the larger storm threat this week). However, this episode provides insight to me, that tropospheric receptivity is heightened for another pulse(s) of momentum transfer, and increased favorability, for my target winter month in the Northeast (January). If anything, the events of this week suggest to me that my January ideas are on track (for NYC: slightly colder than normal, and snowier than normal). A technical SSW is unlikely this winter, but the SPV should be weaker than normal for early-mid January.

My expectation is the NAO will neutralize beyond this week, along with the AO, as the SPV reconsolidates and momentum alters. Thereupon, the Pacific should reorganize into a more conducive structure again, by the end of December. Thereafter, there will be another decline opportunity in the NAO/AO in the month of January, potentially operating contemporaneously with a +PNA and even near neutral EPO. My thoughts remain the same for beyond January. However, this week's storm will increase the probability that NYC's seasonal snowfall ends in the upper portion of my range, assuming the winter pattern continues to proceed as I anticipate.

My projection at this stage for snowfall this week is 6-12" for NYC, a significant snowstorm. Again, the heaviest axis will be a function of z700/z850 proximities.

Thanks! This should easily be the best event since winter 17-18 anyway. Still kinks to be worked out but this is definitely a favorable setup for something quite significant, like you say 6-12" or maybe even more in some places that get stuck under banding. 

[wdrag]

30 minutes ago, uncle W said:

1932-33 was a very mild winter especially in January...it did get a 7" storm on the 17th but very little after that until February...February had a 10" storm...seasonal snowfall was near average...

the 1932 storm from the Brooklyn Eagle...

http://bklyn.newspapers.com/image/59970904/

http://bklyn.newspapers.com/image/59970913

http://bklyn.newspapers.com/image/59971128/

http://bklyn.newspapers.com/image/59971138

Well researched.  Thank you... I plan (if it still applies) to reference daily records at CP of 5.3" for the 16th - 1948, and 17th 6.7 in 1932.  No promises we'll get either.

Gotta rest. Walt

[David-LI]

NAM IS DIGGING! LETS GO!

[HVSnowLover]

NAM looks like it will come in warm but we'll see. Either way it's long range NAM so lets not panic.     

Nevermind everything crashed going to be a strong run