OBS/Totals for 12/26-27 Storm

[gravitylover]

Over 8" and still snowing lightly. I'll get out and measure in a few minutes, there's coffee to be finished before shoveling.

[Dark Star]

This particular discussion is only about Manhattan, specifically Central Park (despite its notorious poor snow depth reportings).  My interpretation is the storm was a bust.  Some could argue, in a broad sense, that the storm was not a bust.  Strangely, all models came on board about 5 days ago that this would be an all snow event.  After 2 days in a row reaching the 40s (or more), the temperature miraculously cooled down just before the clipper like system was to arrive (cold air being one of the ingredients for snow).  The only thing peculiar was that the main dynamics of the storm would be north and east of Manhattan.  Historically, this is not a good recipe for an all snow event.  However, I was optimistic for a good snowfall, based on the model consensus.  EVERYBODY, or so it seemed, was saying that Central Park was going to receive a significant snowfall. I had not seen one of the models 00z run on 12/26/2025, which depicted a lighter amount.  Instead, I was noticing throughout the day on Friday, that after the overcast became solid, had begun thinning, and pretty much cleared at times, in advance of the storm.  Based on experience, 98 times out of 100, if the overcast breaks or the sun becomes visible hours before the storm, it will be a bust.  With the 2 out of the last 100 times occuring within the last 10 years.  You can use that information for now casting.  For now casting, you can pretty much ignore the models and start going on instinct and various real time indicators on what is actually occurring. 

This system will be discussed and argued, many arguing over semantics or defintion.  Some have already said that this system "dry slotted".   I will disagree.  To me, a dry slot occurs when a storm occludes, becomes intense and mature, and forms the standard comma shape.  The intensity of the storm draws in dry air from hundreds of miles away.  This was not the case.  One of the key ingredients for snow, cold air"  was advecting into the system ahead of the storm.  Cold air, as we know, is drier.  The dynamics of the system was not as intense in this area.  Again, the main dynamics were to remain north and east of Manhattan.  Some warned of a "warm nose"  that would cut down on snow totals.  Though not wrong, if the dyamics were as the models depicted, the warm nose most likely would not have changed the snow to sleet, or rain.  The fact is, the precipitation stopped at times after an intial light covering of snow.  With very little lift, virtually no dynamic atmospheric cooling. 

Present HRRR suggests some "back building" of snow into the area, at least through mid morning.  This could bring Central Park nearer to the lower end of the 4" to 8" range, which some will say that the forecasts were accurate.   I disagree.  The dynamics of the storm that were forecast simply missed Manhattan.

[SnoSki14]

2 hours ago, Brian5671 said:

No bust here about 8 inches 

CT cleaned up nicely 

[TriPol]

8 minutes ago, Dark Star said:

This particular discussion is only about Manhattan, specifically Central Park (despite its notorious poor snow depth reportings).  My interpretation is the storm was a bust.  Some could argue, in a broad sense, that the storm was not a bust.  Strangely, all models came on board about 5 days ago that this would be an all snow event.  After 2 days in a row reaching the 40s (or more), the temperature miraculously cooled down just before the clipper like system was to arrive (cold air being one of the ingredients for snow).  The only thing peculiar was that the main dynamics of the storm would be north and east of Manhattan.  Historically, this is not a good recipe for an all snow event.  However, I was optimistic for a good snowfall, based on the model consensus.  EVERYBODY, or so it seemed, was saying that Central Park was going to receive a significant snowfall. I had not seen one of the models 00z run on 12/26/2025, which depicted a lighter amount.  Instead, I was noticing throughout the day on Friday, that after the overcast became solid, had begun thinning, and pretty much cleared at times, in advance of the storm.  Based on experience, 98 times out of 100, if the overcast breaks or the sun becomes visible hours before the storm, it will be a bust.  With the 2 out of the last 100 times occuring within the last 10 years.  You can use that information for now casting.  For now casting, you can pretty much ignore the models and start going on instinct and various real time indicators on what is actually occurring. 

This system will be discussed and argued, many arguing over semantics or defintion.  Some have already said that this system "dry slotted".   I will disagree.  To me, a dry slot occurs when a storm occludes, becomes intense and mature, and forms the standard comma shape.  The intensity of the storm draws in dry air from hundreds of miles away.  This was not the case.  One of the key ingredients for snow, cold air"  was advecting into the system ahead of the storm.  Cold air, as we know, is drier.  The dynamics of the system was not as intense in this area.  Again, the main dynamics were to remain north and east of Manhattan.  Some warned of a "warm nose"  that would cut down on snow totals.  Though not wrong, if the dyamics were as the models depicted, the warm nose most likely would not have changed the snow to sleet, or rain.  The fact is, the precipitation stopped at times after an intial light covering of snow.  With very little lift, virtually no dynamic atmospheric cooling. 

Present HRRR suggests some "back building" of snow into the area, at least through mid morning.  This could bring Central Park nearer to the lower end of the 4" to 8" range, which some will say that the forecasts were accurate.   I disagree.  The dynamics of the storm that were forecast simply missed Manhattan.

If this isn't a dry slot, I don't know what is.

[doncat]

Snowed at a nice mostly moderate with some lighter periods since around midnight here on si....just measured at 4" on the nose, temp down to 25°. Melted of 0.52"..…so all in all not too far off from what was expected for my area . Over 10" for the month now.

[Dark Star]

22 minutes ago, TriPol said:

If this isn't a dry slot, I don't know what is.

"Screw zones", in my defintion, are different than dry slots.  It is an area of poor dynamics.  You are not necessarily incorrect.  The cold air advection out ahead of the storm caused drier air.  However, the main lifting of the storm was always going to be north and east of the this area.  

[WIN]

Measured a touch over 3 inches. Not even an inch when I went to bed last night, so I guess there was some back building.

Short of the 5 to 8 forecast, but I consider it a win considering the way things looked around 11pm last night.

[EasternLI]

Finished up with 5.5" OTG. So December will finish the month with 10"+ of snow over here. That hasn't happened in many years...

[dmillz25]

Got an average of 4.2” here

[doncat]

3 minutes ago, EasternLI said:

Finished up with 5.5" OTG. So December will finish the month with 10"+ of snow over here. That hasn't happened in many years...

To go along with a -4° temp departure...nice wintery month .

[dmillz25]

Central Park 4.3”

[Bxstormwatcher360]

4.7 here..3 inches short of my prediction. Although another good snow snower might get me to an even 5. The snow just kept going overnight.

[coastalplainsnowman]

Looking at the snowfall reports on the Upton site, I'm really surprised to see just 4 reports for Nassau.  I've often seen much more reports for far smaller storms.

Just doing the ruler in the snow thing ths morning I ended up with 4 here.  We did pretty well here from 10PM - 2AM.  Given the initial burst and the compaction due to the sleet component which was there from like 8-10PM, if I was doing this with the board I'm likely more like 5.  That was in the predicted range for my backyard.  Looking at the Suffolk numbers, looks like a forecast that nearly verified or actually verified, just on the low end.

 

[ILoveWinter]

4 minutes ago, dmillz25 said:

Central Park 4.3”

We broke the 4’’ streak!

[Dark Star]

30 minutes ago, Dark Star said:

"Screw zones", in my defintion, are different than dry slots.  It is an area of poor dynamics.  You are not necessarily incorrect.  The cold air advection out ahead of the storm caused drier air.  However, the main lifting of the storm was always going to be north and east of the this area.  

NWS defines a dry slot:  

Dry Slot

A zone of dry (and relatively cloud-free) air which wraps east- or northeastward into the southern and eastern parts of a synoptic scale or mesoscale low pressure system. A dry slot generally is seen best on satellite photographs.

[wthrmn654]

I love having adhd when it snows,  I'm a big kid with bigger toys. 

[SnoSki14]

3 minutes ago, ILoveWinter said:

We broke the 4’’ streak!

So according to the stats of a Nina December, the rest of winter should be pretty good. 

[ForestHillWx]

Eyeballing 2” of snow/ice; but it’s wintry looking outside and snow is falling currently. Never expected all that much, but certainly the sleet-fest was not ideal.

Oh well, it should be enough for the kids snow tubes; onto the next storm! 

[ILoveWinter]

1 hour ago, Dark Star said:

This particular discussion is only about Manhattan, specifically Central Park (despite its notorious poor snow depth reportings).  My interpretation is the storm was a bust.  Some could argue, in a broad sense, that the storm was not a bust.  Strangely, all models came on board about 5 days ago that this would be an all snow event.  After 2 days in a row reaching the 40s (or more), the temperature miraculously cooled down just before the clipper like system was to arrive (cold air being one of the ingredients for snow).  The only thing peculiar was that the main dynamics of the storm would be north and east of Manhattan.  Historically, this is not a good recipe for an all snow event.  However, I was optimistic for a good snowfall, based on the model consensus.  EVERYBODY, or so it seemed, was saying that Central Park was going to receive a significant snowfall. I had not seen one of the models 00z run on 12/26/2025, which depicted a lighter amount.  Instead, I was noticing throughout the day on Friday, that after the overcast became solid, had begun thinning, and pretty much cleared at times, in advance of the storm.  Based on experience, 98 times out of 100, if the overcast breaks or the sun becomes visible hours before the storm, it will be a bust.  With the 2 out of the last 100 times occuring within the last 10 years.  You can use that information for now casting.  For now casting, you can pretty much ignore the models and start going on instinct and various real time indicators on what is actually occurring. 

This system will be discussed and argued, many arguing over semantics or defintion.  Some have already said that this system "dry slotted".   I will disagree.  To me, a dry slot occurs when a storm occludes, becomes intense and mature, and forms the standard comma shape.  The intensity of the storm draws in dry air from hundreds of miles away.  This was not the case.  One of the key ingredients for snow, cold air"  was advecting into the system ahead of the storm.  Cold air, as we know, is drier.  The dynamics of the system was not as intense in this area.  Again, the main dynamics were to remain north and east of Manhattan.  Some warned of a "warm nose"  that would cut down on snow totals.  Though not wrong, if the dyamics were as the models depicted, the warm nose most likely would not have changed the snow to sleet, or rain.  The fact is, the precipitation stopped at times after an intial light covering of snow.  With very little lift, virtually no dynamic atmospheric cooling. 

Present HRRR suggests some "back building" of snow into the area, at least through mid morning.  This could bring Central Park nearer to the lower end of the 4" to 8" range, which some will say that the forecasts were accurate.   I disagree.  The dynamics of the storm that were forecast simply missed Manhattan.

I agree that for NYC the issue was dynamics. Yes there was a bit of sleet that mixed in here and there but any time the rates were actually strong it was all snow. We ended up with 4.3” so technically it was on the low end of the 4-8 forecasts but a 35 mile SW shift would have led to 8 or so. 

[Kaner587]

1 minute ago, ILoveWinter said:

I agree that for NYC the issue was dynamics. Yes there was a bit of sleet that mixed in here and there but any time the rates were actually strong it was all snow. We ended up with 4.3” so technically it was on the low end of the 4-8 forecasts but a 35 mile SW shift would have led to 8 or so. 

In the end in my opinion not a bust and much closer to the original totals expected that many especially on social media suggested. 25-50 miles… 

[bluewave]

Really beautiful event here just east of the HVN ASOS. It came in as a very heavy wall of snow in the evening. We had 2” per hr rates for the first few hours. Then the rates decreased. Finished up here with a very respectable 5.5”.

[ILoveWinter]

1 minute ago, Kaner587 said:

In the end in my opinion not a bust and much closer to the original totals expected that many especially on social media suggested. 25-50 miles… 

It’s an interesting discussion - bust or not - the Park clearly lost a few inches in those first few hours due to poor dynamics and most models didn’t indicate that. There was a point early on where it was literally snowing all around us and we weren’t even flurrying! 

[jm1220]

I’ll go with 4.5” final. A disappointment/underperformer but can’t win ‘em all. Brings me to 13” for the month. 

[GaWx]

 Anyone see LaGuardia’s total? Other than that, I think every NYC official station got 4”+.

C Park was up to 0.49” liquid equiv as of 7AM. Was that that far off? How much liquid was forecasted?

[Volcanic Winter]

Literally a frozen grass flavored mat of peanut brittle . About to take a spoon out to crack it like the world’s worst crème brulee.

Back below freezing, a fully congealed squingealed mass of … crap. 

[RU848789]

4 hours ago, RU848789 said:

Just finished shoveling and it looks like the storm is done, so unless something happens overnight, my final measurement is 1.8", as we got about 0.1" the last hour.  Not as bad as it was looking at 10 pm, but still a pretty significant bust when we were under a winter storm warning for 4-7", my hourly forecast gave me 5.7" this morning, and the average model snowfall was about 5.5" (over 10 models) - and my prediction was 6.1" (oof).  Of course it's way better than the rain and 60F it was looking like 10 days ago, but still disappointing.  Pretty snowfall, though, and loved having temps in the 20s for most of it.  Feels like winter.  Brings me to a healthy 9.6" for December, my most since we got 10.3" in Dec 2017.

Well whaddya know?  We got another 0.3" since 3 am, bringing my total to 2.1", which somehow sounds like less of a bust than 1.8", lol.  Woke up once and saw some light snow and looking at the radar since 3 am I can definitely see another 0.3" (looks like it should've been more, but that's what I measured).  Snowing very lightly now at 25F.  

[the_other_guy]

If CPK got 4.3 this isnt really a bust. Just a low end of the range.

I lived thru busts in the 80s and 90s before we had all this technology in the palm of our hand. You would go to bed expecting snow and you would wake up to grass.

Enjoy it! As someone rightly pointed out, a snowstorm from the NW is a rarity in NYC. Also a rarity (lately) in NYC: a snowy December.

[coastalplainsnowman]

9 minutes ago, ILoveWinter said:

It’s an interesting discussion - bust or not - the Park clearly lost a few inches in those first few hours due to poor dynamics and most models didn’t indicate that. There was a point early on where it was literally snowing all around us and we weren’t even flurrying! 

My layman's take -   In setups like this it's almost like trying to not only predict severe thunderstorms in July, but predict which towns are going to cash in. That was clear to me by the unusually frequent reference to banding in much of the forecasting.  Compare to being under a "widespread thunderstorms" prediction.  Some people get crushed, others get next to nothing. The difference is that in July most people  - not us, but normal people - are just happy to have missed out, and they go about their day, rather than getting on the computer and writing blogs about it.  This is a tough, imprecise business - I give the mets a lot of credit.

[North and West]

My layman's take -   In setups like this it's almost like trying to not only predict severe thunderstorms in July, but predict which towns are going to cash in. That was clear to me by the unusually frequent reference to banding in much of the forecasting.  Compare to being under a "widespread thunderstorms" prediction.  Some people get crushed, others get next to nothing. The difference is that in July most people  - not us, but normal people - are just happy to have missed out, and they go about their day, rather than getting on the computer and writing blogs about it.  This is a tough, imprecise business - I give the mets a lot of credit.

funny way to spell “unhinged lunatics” as “not us”


.

[Kaner587]

16 minutes ago, ILoveWinter said:

It’s an interesting discussion - bust or not - the Park clearly lost a few inches in those first few hours due to poor dynamics and most models didn’t indicate that. There was a point early on where it was literally snowing all around us and we weren’t even flurrying! 

Agree but total qpf about 0.50 you’re not going to clear 6 with that