January 28-30th Possible Nor'easter

[CPcantmeasuresnow]

-3°, snow pack aiding in the cool down.

[the_other_guy]

1 minute ago, tim said:

-1° now....I'm @+9°..wow!!

Radiational cooling  at its finest..

FOK is amazing.

One day we’ll find out there was a piece of ice on the thermometer

[LibertyBell]

1 minute ago, tim said:

-1° now....I'm @+9°..wow!!

Radiational cooling  at its finest..

and HTO at 2.

 

Is FOK the actual coldest spot on long island? There isn't a place a few miles from there thats even colder?  Weird coincidence to have the airport sensor at just the right location to record the coldest temps, I'm sure it wasn't planned that way lol.

Meanwhile JFK is 16 and LGA is 19.

 

[LibertyBell]

1 minute ago, CPcantmeasuresnow said:

-3°, snow pack aiding in the cool down.

Not at FOK lol where it's -1

 

[psv88]

8 degrees here. Cold is around

[LibertyBell]

2 minutes ago, bluewave said:

Better data assimilation closer to storm time.

 

 

Oh okay so there really is no nudge, the apparent nudge is just the result of imperfect data assimilation prior to more recent runs?

[Tatamy]

06z Euro shifts east

[coastalplainsnowman]

18 minutes ago, LibertyBell said:

what are they measuring temps on, a slab of dry ice?

 

 

4 minutes ago, LibertyBell said:

HTO (East Hampton) at 3 degrees, so not far off from the FOK 0 temp.

Wow now FOK down to -1 (is this their first below zero this season?)  HTO holding at 3  (edit- HTO now down to 2.)

It just seems weird that the airport sensor seems to be right where the coldest temps on Long Island are-- what a coincidence lol.  Are we sure there isn't some nearby place around there that might be even colder?

 

Here's what I've learned this on this forum about this, but if I'm messing up this answer someone let me know.  It's the apparently sandy soil at that location which makes for great radiational cooling.  It's probably calm there currently.  With a little breeze the disparity would largely disappear.   

The thing that's always still interesting to me regardless is when there are times in the past where they'll have a temp like this ahead of a cutter, and soon as things start going, their temp is instantly, like immediately,  in line with their neighbors.

 

 

[bluewave]

Just now, LibertyBell said:

Oh okay so there really is no nudge, the apparent nudge is just the result of imperfect data assimilation prior to more recent runs?

The next several runs will be decisive. But even the runs 24hrs before the January 2000 event were way off. Tiny initialization errors throw the models off.

https://journals.ametsoc.org/view/journals/mwre/130/4/1520-0493_2002_130_0957_icsaeg_2.0.co_2.xml

Short- and medium-range (24–96-h) forecasts of the January 2000 U.S. east coast cyclone and associated snowstorm are examined using the U.S. Navy global forecast model and adjoint system. Attention is given to errors on the synoptic scale, including forecast position and central pressure of the cyclone at the verification time of 1200 UTC 25 January 2000. There is a substantial loss of predictive skill in the 72- and 96-h forecasts, while the 24- and 48-h forecasts capture the synoptic-scale features of the cyclone development with moderate errors. Sensitivity information from the adjoint model suggests that the initial conditions for the 72-h forecast starting at 1200 UTC 22 January 2000 contained relatively small, but critical, errors in upper-air wind and temperature over a large upstream area, including part of the eastern Pacific and “well observed” areas of western and central North America. The rapid growth of these initial errors in a highly unstable flow regime (large singular-vector growth factors) is the most likely cause of the large errors that developed in operational short- and medium-range forecasts of the snowstorm. The large extent of the upstream sensitive area in this case would appear to make “targeting” a small set of new observations an impractical method to improve forecast skill. A diagnostic correction (derived from adjoint sensitivity information) of a part of the initial condition error in the 72-h forecast reduces the forecast error norm by 75% and improves a 1860-km error in cyclone position to a 105-km error. This demonstrates that the model is capable of making a skillful forecast starting from an initial state that is plausible and not far from the original initial conditions. It is also shown that forecast errors in this case propagate at speeds that are greater than those of the synoptic-scale trough and ridge features of the cyclone.

[Tatamy]

06z Euro has 3-6” across the area with 6”+ across eastern LI and down closer to ACY in S NJ.  Lesser amounts to the N&W.

[qg_omega]

Euro is just so bad now with east coast storms, really unusable 

[gravitylover]

5 minutes ago, LibertyBell said:

Oh okay so there really is no nudge, the apparent nudge is just the result of imperfect data assimilation prior to more recent runs?

Questionable or no info going in can't give a proper solution, can it?

2 minutes ago, coastalplainsnowman said:

 

Here's what I've learned this on this forum about this, but if I'm messing up this answer someone let me know.  It's the apparently sandy soil at that location which makes for great radiational cooling.  It's probably calm there currently.  With a little breeze the disparity would largely disappear.   

The thing that's always still interesting to me regardless is when there are times in the past where they'll have a temp like this ahead of a cutter, and soon as things start going, their temp is instantly, like immediately,  in line with their neighbors.

 

 

I have a feeling that if you went out into the pine barrens and put thermometers in some of the hollows away from hard surfaces like runways you'd find slightly lower temps. Of course the temps balance out quickly, a little bit of mixing moves the air around and up goes the temp.

[Wxnyc]

16 minutes ago, LibertyBell said:

What causes the nudges? And why cant they be forecast better?

 

I’ve been asking that for years, some people are nudges and nudniks . 
(Hi from a fellow Sullivan county homeowner .) I’m staying in Brooklyn for this one.

[jm1220]

1 minute ago, qg_omega said:

Euro is just so bad now with east coast storms, really unusable 

It’s been on this amped trend which other models look to be picking up which is a feather in its cap here it seems. 

0z and 6z both went east though and now NYC is at the edge of a warning event on the model. Want that to reverse obviously. It has the stall/capture too far NE. 

[LibertyBell]

8 minutes ago, coastalplainsnowman said:

 

Here's what I've learned this on this forum about this, but if I'm messing up this answer someone let me know.  It's the apparently sandy soil at that location which makes for great radiational cooling.  It's probably calm there currently.  With a little breeze the disparity would largely disappear.   

The thing that's always still interesting to me regardless is when there are times in the past where they'll have a temp like this ahead of a cutter, and soon as things start going, their temp is instantly, like immediately,  in line with their neighbors.

 

 

Yes the cold air is right near the ground therefore it takes very little to displace it.  There is an inversion there because of the calm winds.

 

[LibertyBell]

2 minutes ago, gravitylover said:

Questionable or no info going in can't give a proper solution, can it?

I have a feeling that if you went out into the pine barrens and put thermometers in some of the hollows away from hard surfaces like runways you'd find slightly lower temps. Of course the temps balance out quickly, a little bit of mixing moves the air around and up goes the temp.

It's pretty interesting, I've tried the WU network but none of them quite reaches the levels of FOK....the closest one to it is in Quogue I think.

Yep as far as bad data goes it's GIGO just like with anything else lol

 

[EasternLI]

It's got a double barrel low look to it. With some vorticity running out in front of the main trough. The trough is a bit broad. It delayed the capture a little bit. Would be nice to see a tighter/sharper trough. Let's see what else today brings. 

[LibertyBell]

11 minutes ago, bluewave said:

The next several runs will be decisive. But even the runs 24hrs before the January 2000 event were way off. Tiny initialization errors throw the models off.

https://journals.ametsoc.org/view/journals/mwre/130/4/1520-0493_2002_130_0957_icsaeg_2.0.co_2.xml

Short- and medium-range (24–96-h) forecasts of the January 2000 U.S. east coast cyclone and associated snowstorm are examined using the U.S. Navy global forecast model and adjoint system. Attention is given to errors on the synoptic scale, including forecast position and central pressure of the cyclone at the verification time of 1200 UTC 25 January 2000. There is a substantial loss of predictive skill in the 72- and 96-h forecasts, while the 24- and 48-h forecasts capture the synoptic-scale features of the cyclone development with moderate errors. Sensitivity information from the adjoint model suggests that the initial conditions for the 72-h forecast starting at 1200 UTC 22 January 2000 contained relatively small, but critical, errors in upper-air wind and temperature over a large upstream area, including part of the eastern Pacific and “well observed” areas of western and central North America. The rapid growth of these initial errors in a highly unstable flow regime (large singular-vector growth factors) is the most likely cause of the large errors that developed in operational short- and medium-range forecasts of the snowstorm. The large extent of the upstream sensitive area in this case would appear to make “targeting” a small set of new observations an impractical method to improve forecast skill. A diagnostic correction (derived from adjoint sensitivity information) of a part of the initial condition error in the 72-h forecast reduces the forecast error norm by 75% and improves a 1860-km error in cyclone position to a 105-km error. This demonstrates that the model is capable of making a skillful forecast starting from an initial state that is plausible and not far from the original initial conditions. It is also shown that forecast errors in this case propagate at speeds that are greater than those of the synoptic-scale trough and ridge features of the cyclone.

How many miles were the models off by 24 hours before that event and right when the event began? Was it a 20 mile error?  

 

[gravitylover]

Just now, LibertyBell said:

It' I've tried the WU network but none of them quite reaches the levels of FOK....

 

The sites on WU are generally private property and sometimes businesses and those are all developed spaces of some sort so will be warmer than 1/4 mile away where it's undeveloped. When you're looking for a difference of just a few degrees that's where you'll find it, developed vs undeveloped. Like I said, take a thermo and go for a walk, I bet you'll find what you're looking for.

[EasternLI]

The low is kind of on a blob of convection. Wonder if that's real. Sometimes it is, sometimes it isn't. If it isn't, would be a better solution I think. 

[the_other_guy]

13 minutes ago, Tatamy said:

06z Euro has 3-6” across the area with 6”+ across eastern LI and down closer to ACY in S NJ.  Lesser amounts to the N&W.

My gut says we should be happy if we get this.

I just can’t dismiss the east GFS.

Not this January.

If it came back west I would feel better.

[lee59]

21 minutes ago, LibertyBell said:

and HTO at 2.

 

Is FOK the actual coldest spot on long island? There isn't a place a few miles from there thats even colder?  Weird coincidence to have the airport sensor at just the right location to record the coldest temps, I'm sure it wasn't planned that way lol.

Meanwhile JFK is 16 and LGA is 19.

 

I find on nights with no wind and clear skies, especially in winter, temperature differences in short distances can be extreme. I have  seen 5 degrees difference from 2 weather stations at my house, one 6ft. above the ground and out in the open and the other above a shed 20ft. in the air. The one 6ft. above the ground and in the open is colder. 

[qg_omega]

5 minutes ago, the_other_guy said:

My gut says we should be happy if we get this.

I just can’t dismiss the east GFS.

Not this January.

If it came back west I would feel better.

I think that’s the high bar, decent chance of not a flake and tons of Virga for NYC.  Going to have super dry air funneling right down the Hudson Valley.  Remember the last storm the Euro had a few inches where only a few flakes actually happened.  Never bet against the GFS when its so locked in as it has been for days.  Just remarkable consistency.

[jm1220]

15 minutes ago, EasternLI said:

The low is kind of on a blob of convection. Wonder if that's real. Sometimes it is, sometimes it isn't. If it isn't, would be a better solution I think. 

I guess we’ll see. It really can happen, happened with our last storm. Hopefully the UK/GGEM last night didn’t overcorrect. GFS still being stubborn obviously but it’s probably way too suppressed and it’s up to old tricks. 

My ‘bar’ for NYC is a 4-6” type event, be thrilled with more than that. 

[EasternLI]

3 minutes ago, jm1220 said:

I guess we’ll see. It really can happen, happened with our last storm. Hopefully the UK/GGEM last night didn’t overcorrect. GFS still being stubborn obviously but it’s probably way too suppressed and it’s up to old tricks. 

My ‘bar’ for NYC is a 4-6” type event, be thrilled with more than that. 

Yeah, I'm not really sure what to expect. Really interested in what the models spit out today and tomorrow. Such a sensitive setup. 

[Blizzardo]

At this stage.. NYC and west could be 2" or 2'....

[eduggs]

Even on the 0z UK and CMC, the SLP is pretty far offshore. Synoptically, these usually impact primarily coastal regions and LI. 

[EasternLI]

06z EPS 

[MJO812]

54 minutes ago, qg_omega said:

Euro is just so bad now with east coast storms, really unusable 

Dude every model just went west at 0z. Let's see how the 12z runs are.

[MJO812]

51 minutes ago, jm1220 said:

It’s been on this amped trend which other models look to be picking up which is a feather in its cap here it seems. 

0z and 6z both went east though and now NYC is at the edge of a warning event on the model. Want that to reverse obviously. It has the stall/capture too far NE. 

And meanwhile every other models went west