OBS for NYC CP first measurable minor snowfall? 11A Fri 12/20-11A 12/21, embedded with surrounding area periodic minor accumulative snow

[wdrag]

No guarantees on what will happen. Modeling showa a pair of closely following short waves diving southeast toward the mid Atlantic coast, sharpening the mid level trough.  While too far offshore for a 4+" event, the 850 MB weak warm advection, 850MB vorticity from s central NYS sewd to NNJ and under running boundary layer northerly flow is going to produce a little bit of snow.  

For CP, think it needs to measure after sundown Fri.  Outskirts of NYC from NNJ-se NYS-sw CT across LI should see 1/4" to maybe as much as 2", with potential for 3" near the NYS-PA nw NJ border. 

4AM NWS has not posted any snowfall for NYC, so the probability (attached) for 0.1" in CP is very low (26%).

Added 08z WSSI-P graphic and the NWS 08z/18 Blend of Models.

If the system ends up weaker and not sharpening, then this modeled event fritters (850 vort trough just becomes general northerly CAA flow instead of what is modeled now).  Should the miD level trough sharpen a bit more then that boosts confidence for NYC metro spirits brightened by snow on the ground Saturday morning.

If PHL measures, that would be their first of the year.  BOS already has measured.

Reserving comment for Christmas possibilities to the general Dec thread for now, will we get through 12z Sat. Click graphics for clarity.805A

 

Added OBS to the title at 748A/20 and one updated prob graphic for NYC CP

[snowman19]

All the 12z models today are an inch or less total for Friday/Friday night

[ILoveWinter]

43 minutes ago, snowman19 said:

All the 12z models today are an inch or less total for Friday/Friday night

Weren’t you adding weenies to anyone posting there’s a chance of snow in the immediate metro as recently as yesterday? 

[ForestHillWx]

Dude’s the “Heatmiser” of any winter thread. 

Thanks for making it Walt, even if it’s just pixie dust. 

[North and West]

All the 12z models today are an inch or less total for Friday/Friday night

Sounds like an early Christmas gift for you, Ebenezer.


.

[uofmiami]

[MJO812]

The norlun will keep moving around 

[MJO812]

No talk about the Nam ? Very close. Eastern LI and SNE Snowstorm.

[Stormlover74]

[MJO812]

4 minutes ago, Stormlover74 said:

Outlier atm but I wonder if the models are wrong about the norlun and the low ends up more west.

The flow is fast so not sure how far west it can come.

[Tatamy]

8 minutes ago, MJO812 said:

No talk about the Nam ? Very close. Eastern LI and SNE Snowstorm.

You do realize that the NAM is literally an ocean apart from all the other guidance.  Good luck with the remaining runs from the 0z suite.

[MJO812]

1 minute ago, Tatamy said:

You do realize that the NAM is literally an ocean apart from all the other guidance.  Good luck with the remaining runs from the 0z suite.

We can't talk about it on a weather forum ?

 

Weird

[psv88]

3 minutes ago, MJO812 said:

We can't talk about it on a weather forum ?

 

Weird

You are currently talking about it. Were your posts deleted? I’m confused as to why you think you can’t?

[MJO812]

2 minutes ago, psv88 said:

You are currently talking about it. Were your posts deleted? I’m confused as to why you think you can’t?

Because people posting smart remarks on this subforum.  

[Allsnow]

1 minute ago, MJO812 said:

Because people posting smart remarks on this subforum.  

It’s the nam.

should be tossed until 24 hours out 

[psv88]

3 minutes ago, MJO812 said:

Because people posting smart remarks on this subforum.  

You’re a cop. Toughen up. 

[cardinalland]

meanwhile the NAM 3km is dry as a bone

[RU848789]

@wdrag- for this event, the NBM has consistently shown higher snowfall amounts than all of the major models that most people look at regularly at places like Pivotal and TT (i.e., the Euro, GFS, CMC, UK, NAM, RDPS, etc.) and a decent amount more than the NWS is predicting.  I assume this means that the rest of the NBM models (there are many more as per the link below) are showing a decent amount more snowfall than the more commonly used models.  I've also always wondered if the NBM model obtains inputs from other models earlier than the public does, since the NBM output is available well before most of the model outputs are available.  Any insights on this (or from other folks who might know)?  Thanks.  

https://www.weather.gov/news/200318-nbm32#:~:text=The National Weather Service (NWS,their analysis of the data.

 

 

[NEG NAO]

2 hours ago, MJO812 said:

We can't talk about it on a weather forum ?

 

Weird

We can talk about it because in situations and setups similar to Friday night into Saturday and especially with a possible Norlons - models have a hard time handling those especially a couple days in advance IMO some areas will over perform BUT where ?

[RU848789]

Surprised nobody mentioned the AFD from Mt. Holly discussing the possibility of an overperforming inverted trough...

For now, the best chance of observing accumulating snow will be across the Lehigh Valley, northern New Jersey and in the Poconos where temperatures will be cooler through the duration of the event. Current forecast snow totals in these areas are for between 1-2", locally up to 3". Light accumulations of a dusting up to 1" are possible across the remainder of New Jersey, Pennsylvania and northern Delaware as rain transitions to snow on Friday night as temperatures cool below/near freezing. It should be noted though that these type of inverted trough setups are notoriously difficult to forecast as they can sometimes have localized heavier precipitation amounts. If this occurs, some areas could "over perform" and see snowfall amounts as high as 4 or 5 inches. Best chances for this would be central into NW NJ, NE PA.

[winterwx21]

Euro looks a little better on the 0z run and gives us some snow Friday night into Saturday morning. We certainly have a shot at seeing an inch of snow out of this. It's not going to be a major event obviously, but I'd love to see a little accumulating snow. With the amount of cold air we're getting this December, it would be pretty disappointing if we can't even squeeze out an inch of snow. Hopefully it'll happen Friday night. 

[NEG NAO]

6 minutes ago, winterwx21 said:

Euro looks a little better on the 0z run and gives us some snow Friday night into Saturday morning. We certainly have a shot at seeing an inch of snow out of this. It's not going to be a major event obviously, but I'd love to see a little accumulating snow. With the amount of cold air we're getting this December, it would be pretty disappointing if we can't even squeeze out an inch of snow. Hopefully it'll happen Friday night. 

agreed - anything is possible - no one was expecting that heavy slim west to east band to set up in the Central NJ during last Feb 16 -17 event - but could still go the other way with little or nothing - good chance though that this will end up being a now casting event watching rain - snow lines on radar and heavier precip developing changing to snow as the event wears on.........

[LVblizzard]

Late night SREF with a pretty sizable shift towards a stronger and farther west system.

[binbisso]

6z nam. It's the only model showing this but is it on to something. 

[binbisso]

3k nam probably more realistic.  Nice for LI

[Tatamy]

3 minutes ago, binbisso said:

6z nam. It's the only model showing this but is it on to something. 

It was mainly alone on the 0z run however now with the 06z run it is getting some support from the 3k NAM.  It’s kind of a long shot but let’s see what the rest of the models do as we go through the day.

[MJO812]

Icon says Nam drunk lol. Still has a weak trough. It did shift the low slightly more west.

[MJO812]

0z Ukie was well west of 12z

[Snowlover11]

Nam doing Nam things?

[MJO812]

13 minutes ago, Snowlover11 said:

Nam doing Nam things?

Possibly but every model has ticked west somewhat.