Potential extensive winter event, I-95 west and with again a chance for NYC first inch(es) of snow Mon or more likely Tue Jan 16, 2024 (serves as OBS thread as well)

[Tatamy]

5 minutes ago, SnowGoose69 said:

This little virga area has helped saturate the atmosphere down to 5-6,000 over the metro...its still 8-9,000 further north in the LHV.  You need ceilings down to around 3500-4000 to begin snowing so this has helped that cause somewhat.  Snow should reach the ground by NYC by 8-9pm at worst

I have been seeing flurries for a couple of hours already and this relates directly to what you stated above.

[Allsnow]

People downplaying this event are the same who played up the rain/wind event a few days ago 

[MJO812]

[MJO812]

1 minute ago, Allsnow said:

People downplaying this event are the same who played up the rain/wind event a few days ago 

Gfs kuchera has 3-5 inches for NYC with more to the west.

Everyone will be snowing tonight in the 20s. Ratios will be slightly higher. 

 

 

[Dark Star]

31 minutes ago, MJO812 said:

It didn't even start

There is precip moving over us, just not reaching the ground.  It will take a while to break through...

[Picard]

That is really going to struggle to get any further north than it is right now, at least for many more hours.  These near zero dewpoints are going to be hard to overcome.  I'm a little skeptical of 4-6". 

[Allsnow]

2 minutes ago, Dark Star said:

There is precip moving over us, just not reaching the ground.  It will take a while to break through...

Stop…main accumulation comes from the warm air advection precipitation. 

[the_other_guy]

21 minutes ago, jm1220 said:

If your expectation is for a couple inches to make it wintry outside, maybe 3” if lucky around the city, coast you’ll probably be fine. If you’re holding out for 4” or more you’ll probably be disappointed. Models including the LOL worthy but predictable late NW bump ones show the best snow NW of the city where it won’t change over. This isn’t a major event by any means but will put us all on the board finally. Hopefully Friday will be better. Considering there were zero threats until now it’s a big improvement. 

^This

[SnowGoose69]

5 minutes ago, Picard said:

That is really going to struggle to get any further north than it is right now, at least for many more hours.  These near zero dewpoints are going to be hard to overcome.  I'm a little skeptical of 4-6". 

 

Its more the main mechanism to get precip here won't start to move north for a bit...I'd say 830-9pm it begins but this front running area was always expected to mostly miss..you should begin to start seeing the area down in N VA and the Delmarva accelerate due north in the next 1-2 hours 

[Rjay]

12 minutes ago, Picard said:

That is really going to struggle to get any further north than it is right now, at least for many more hours.  These near zero dewpoints are going to be hard to overcome.  I'm a little skeptical of 4-6". 

4-6" looks like a good bet in Sparta 

[Rjay]

16 minutes ago, Allsnow said:

People downplaying this event are the same who played up the rain/wind event a few days ago 

I loved my nighttime squall line 

[Tatamy]

6 minutes ago, SnowGoose69 said:

 

Its more the main mechanism to get precip here won't start to move north for a bit...I'd say 830-9pm it begins but this front running area was always expected to mostly miss..you should begin to start seeing the area down in N VA and the Delmarva accelerate due north in the next 1-2 hours 

Strongly agree.  Best snows that I have seen are in the western Philly suburbs.  They have a coating on the ground near West Chester.

[RU848789]

35 minutes ago, SnowGoose69 said:

Sort of what I said I was worried about this AM....system ticks a bit closer where we still get decent snows but guaranteed we get a wetter period of FZRA...hopefully its more sleet...the QPF seems to be ticking up which is not a surprise.  I could see places near the city ending up with 5 inches before it changes over if there is any banding at all

NAM and RGEM have consistently shown that freezing rain risk after about 9 am or so, but the globals either have all snow for 95 or a later changover to sleet or freezing rain. Freezing rain sucks, as it's dangerous and aesthetically unpleasing. Saving grace could be that it'll mostly be falling on top of snow, forming a crust and not falling on bare ground forming ice rinks.  It also could rob many of us along 95 and even a bit NW/SE of 95 of 0.1-0.2" QPF (or 1-2" of snow), which would also suck.  Hopefully the Euro is right on this.  Thoughts on how this might play out?  

 

[Picard]

5 minutes ago, Rjay said:

4-6" looks like a good bet in Sparta 

My only point is that, at some point, the dry air is relevant.  The models have probably improved over the years in it's consideration, but in the past, in my non-expert experience, they used to suck at it, and 6 inch forecasts evaporated into little more than a heavy dusting for some of us.

[SnowGoose69]

3 minutes ago, Picard said:

My only point is that, at some point, the dry air is relevant.  The models have probably improved over the years in it's consideration, but in the past, in my non-expert experience, they used to suck at it, and 6 inch forecasts evaporated into little more than a heavy dusting for some of us.

Models have been fairly good now for about 25-30 years on that...pre ETA days before 1994 you often smoked cirrus but once the grid resolution began increasing that became way less an issue.  

[Volcanic Winter]

Literal white sand coming down in western TR / Manchester border @ 27 degrees. 

Let’s go!

[psv88]

15 minutes ago, RU848789 said:

NAM and RGEM have consistently shown that freezing rain risk after about 9 am or so, but the globals either have all snow for 95 or a later changover to sleet or freezing rain. Freezing rain sucks, as it's dangerous and aesthetically unpleasing. Saving grace could be that it'll mostly be falling on top of snow, forming a crust and not falling on bare ground forming ice rinks.  It also could rob many of us along 95 and even a bit NW/SE of 95 of 0.1-0.2" QPF (or 1-2" of snow), which would also suck.  Hopefully the Euro is right on this.  Thoughts on how this might play out?  

 

That’s ugly, yikes 

[NorthShoreWx]

39 minutes ago, RU848789 said:

NAM and RGEM have consistently shown that freezing rain risk after about 9 am or so, but the globals either have all snow for 95 or a later changover to sleet or freezing rain. Freezing rain sucks, as it's dangerous and aesthetically unpleasing. Saving grace could be that it'll mostly be falling on top of snow, forming a crust and not falling on bare ground forming ice rinks.  It also could rob many of us along 95 and even a bit NW/SE of 95 of 0.1-0.2" QPF (or 1-2" of snow), which would also suck.  Hopefully the Euro is right on this.  Thoughts on how this might play out?  

 

 

But for a good part of that quarter inch of freezing rain along the north shore, the NAM forecast soundings shows a 50 - 100mb deep sub freezing layer (decreasing over time) from the surface up*.  I forget the magic numbers, but I'd imagine that some of that fzr would be sleet.  3k NAM does eventually get to an obvious fzr sounding and then a wee bit of plain drizzle before things cool again.

I'll take a stand and go with  4" in my neighborhood.  How much it packs down with the phase shifts is TBD.

 

*Caveat is I'm extrapolating from the skew-Ts on the free TT site.  Hard to be precise on some of that fine stuff.

[Volcanic Winter]

2 hours ago, The 4 Seasons said:

Congrats guys on possibly the biggest storm in 2 years for the city. We're going with a widespread 2-5" for the tri-state area, a bit higher than what okx currently has but i think theyll tick up with pm forecast. 

Gah, right on the line of 1-2 and 2-5. That’s okay I only ever expected 1-2 and I really hope I at least see that!

[WestBabylonWeather]

Temp 28 dp 9 as per my ambient station 

[BxEngine]

59 minutes ago, Picard said:

That is really going to struggle to get any further north than it is right now, at least for many more hours.  These near zero dewpoints are going to be hard to overcome.  I'm a little skeptical of 4-6". 

I sure hope the next versions of the models take in the atmospheric conditions so they dont print out 4” of snow when it wont happen because of a dry column….

[Volcanic Winter]

4 minutes ago, BxEngine said:

I sure hope the next versions of the models take in the atmospheric conditions so they dont print out 4” of snow when it wont happen because of a dry column….

I was supposed to get a decent amount from the ACY storm Jan 2-3 ‘22. Right up until go time I was modeled for a few solid inches and I got nothing but virga. Granted the dry air was super aggressive to our north I recall, but yeah the models didn’t really depict it well wrt snow totals along a tight gradient.

IIRC I was within the northern extent of the banding almost the whole time but it just wasn’t reaching the ground. 

[snywx]

23/-1 here

[Picard]

4 minutes ago, snywx said:

23/-1 here

Admit I am a little worried about this.  It's a desert up here.

[BxEngine]

1 minute ago, Volcanic Winter said:

I was supposed to get a decent amount from the ACY storm Jan 2-3 ‘22. Right up until go time I was modeled for a few solid inches and I got nothing but virga. Granted the dry air was super aggressive to our north I recall, but yeah the models didn’t really depict it well wrt snow totals along a tight gradient.

IIRC I was within the northern extent of the banding almost the whole time but absolutely nothing reached the ground.

Models fail at different points all the time for sure, especially when it matters to weenies such as us who debate over 2” vs 4”. Theyll never be perfect, especially when small distances matter significantly with a dry column, lack of uplift, subsidence, etc all over a mile or two at times. But that doesnt mean the models have failed, or that they didnt take into account certain conditions properly. 
 

its along the same lines as when people here complain that once a model has locked on a rainstorm, it never waivers. Complete nonsense. It wavers constantly, its just that sometimes the rain/snow line is in suffolk county, and we all watch the battle and waffling of the model runs….and sometimes the rain snow line is near buffalo. The model performance is identical, but because we are entrenched in the warm sector, 100 miles either way makes no difference, let alone 5 or 10 miles. 

[Volcanic Winter]

 

First flakes sticking to surfaces. 
 

[the_other_guy]

1 hour ago, MJO812 said:

given where the storm is now and the fact that LaGuardia is supposed to be over to a mix of rain and snow by 7 AM and then all rain by 9 AM, I’ll call bullshit on this map early on.

 

I hope I’m wrong, but something happened here today where this changeover is happening a lot earlier than was originally forecast.

 

 

[Rjay]

2 minutes ago, Picard said:

Admit I am a little worried about this.  It's a desert up here.

Between 9pm-12am you should see a significant jump in DP

[SBUWX23]

4 minutes ago, Picard said:

Admit I am a little worried about this.  It's a desert up here.

Go have some dinner, watch some TV and trust meteorology here.

[SnowGoose69]

1 minute ago, the_other_guy said:

given where the storm is now and the fact that LaGuardia is supposed to be over to a mix of rain and snow by 7 AM and then all rain by 9 AM, I’ll call bullshit on this map early on.

 

I hope I’m wrong, but something happened here today where this changeover is happening a lot earlier than was originally forecast.

 

 

 

I think the TAFs are a tad too fast at the airports...RASN at LGA by 12Z just seems crazy to me...I'd say PLSN or FZRAPL by 14-15Z makes more sense.  The TAFs tend to be automated these days now anyway so often they can disagree with the grids