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

wdrag

By wdrag,
in New York City Metro

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wdrag

wdrag

Posted
Posted

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

Screen Shot 2024-12-18 at 4.30.39 AM.png

Screen Shot 2024-12-18 at 6.04.04 AM.png

Screen Shot 2024-12-18 at 7.31.36 AM.png

Screen Shot 2024-12-18 at 4.25.01 AM.png

Screen Shot 2024-12-18 at 3.22.31 AM.png

Screen Shot 2024-12-20 at 7.51.26 AM.png

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donsutherland1
donsutherland1

Four photos from a wonderful way to start the winter solstice. As @MJO812 has noted, all snow is good snow.

wdrag
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

Nibor
Nibor

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psv88

psv88

Posted
Posted
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?

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RU848789

RU848789

Posted
Posted

@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.

 

snowfall_acc-imp.us_ma.png

 

PHI_Snow.png

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NEG NAO

NEG NAO

Posted
Posted
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 ?

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RU848789

RU848789

Posted
Posted

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.

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winterwx21

winterwx21

Posted
Posted

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. 

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NEG NAO

NEG NAO

Posted
Posted
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.........

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Tatamy

Tatamy

Posted
Posted
3 minutes ago, binbisso said:

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

image.thumb.png.be90e030c7a79fd00dd22d6bf7e4e8de.png

image.thumb.png.b8d7fd61acc745e1cc4bb9dd0c9d782c.png

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.

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