Jan 20-22 Threat Potential Part 3

[ag3]

Where are you getting this from? I'm showing it only out to 30hrs on the NCEP site.

The NCEP experimental site is out to 51 hours and so is ewall.

Here's a link to the NCEP experimental site:

http://mag.ncep.noaa.gov/NCOMAGWEB/appcontroller?prevPage=Model&MainPage=index&model=GFS&area=NAMER&areaDesc=North+America+-+US%2C+Canada%2C+and+northern+Mexico&page=Model&prevModel=GFS&prevArea=&currKey=region&prevKey=region&cat=MODEL+GUIDANCE

[nzucker]

Yup, this is pretty much what I was saying. I don't understand how there can be much of an argument. I posted the image on the last page but here it is again for reference. It's not even close, and it's pretty cut and dry (no pun intended) as to why the NAM is less amplified, doesn't have the cyclogenesis nearer to the coast, and is much later to develop the cyclone.

That just shows how bad these models are, ridiculous changes in s/w phasing for a 12 hour margin...one looks as if it's headed to a full-blown Nor'easter whereas the latter is a glancing blow at most.

[earthlight]

Northern stream was never progged to dive very far south - even on the great NAM runs. Reason being it was embedded in progressive ridge/trof sequence. Without a deep trof in the center of the US, even if the southern stream s/w were to get out ahead and phase into the downstream flank, the developing SLP would move quickly to the NE until slowing somewhere up toward the Maritimes (upon interacting with upper level lows). Even those good NAM runs bombed out the low to our NE. So of course I agree the timing and location of phasing is/was important here, but it was never my primary concern with respect to getting a decent snowstorm across our area. If we had some north atlantic blocking that would jam up the flow and allow the northern stream to dig south, that could have produced a good storm even if it had squashed the southern stream energy. In short, it was the largescale features that were misplaced, not so much to quality of the phase that I was keying on.

I said from the start I thought this would be moderate snowstorm at BEST and the low would bomb too late (for us) in the Maritimes... because of the overall synoptic pattern. I thought we were too far SW even with a good phase for a major snow. I was cautious and I contested terms like historical and epic and argued my case. BI tends to lean towards the hype and the upper end of possibilities. That sometimes rubs me the wrong way, especially in situations that are unideal from the start. Being a good forecasters means recognizing situations where odds are stacked against you. He has yet to demonstrate that kind of perception to me.

How can you say that the northern stream wasn't forecast by any model to dive that far south? The NAM had 510dm heights in the Central Great Lakes and a significant shortwave with impressive height falls over the Mississippi Valley! What kind of world are you living in? Again, you're ignoring the simple facts. You're saying that the NAM bombed the low out too far northeast. The NAM for four or more runs had a sub 988mb low pressure system off the NJ Coast along the baroclinic zone. What else are you looking for here? A Dec 26 978mb low pressure 50 miles south of Montauk Point? Sorry, that's fantasy land man.

Listen, you're already backing away from your main argument which was that the phase meant nothing. That was incorrect. Now you're reverting to calling out one of the best forecasters on the board for his inability to demonstrate a perception for the possibility of a storm failure. The guy posted probably 10 or more times that the odds were stacked against us.

It seems to be that you haven't been around the past few days, have missed some significant discussion and have missed some key operational guidance. I suggest you peruse the threads before making such bold statements. I'm all for analytical discussion, but come on man. This is a pretty weak argument if you ask me.

[eduggs]

The NAM had four or more runs where there was a 988 or lower mb low pressure system developing northeast from Ocean City, MD to just south of Montauk. All of those runs featured a well timed phase. Does that really go into your dictionary as a glancing blow?

Yes. If you consider the forward speed of the SLP and the lack of a mid-level center offshore, synoptically they were precisely glancing blows. Sure, the modestly strong SLP and 1" liquid equivalent makes for a good counterpoint, but I thought this was somewhat overdone considering the frontside only precip and short duration. Quite simply, we were situated too far SW on the charts, with respect to the mid and upper levels, so even a perfect phase "glanced" us. And yes, I am speaking relatively here.

[donsutherland1]

18z GFS: 0.26" for NYC

[SnowGoose69]

In response to someone's post...yes...the northern disturbance should be better sampled tonight so we'll see what happens...those northern disturbances often wreak havoc during these La Ninas.

[jasonli18t]

Maybe this is just a stupid question, but will the 0z runs have better sampling of data tonite or are all of the players already on the field (so to speak)?

Boy it's COLD on the east end i wonder why that hasn't worked right since you joined....

[NortheastPAWx]

In response to someone's post...yes...the northern disturbance should be better sampled tonight so we'll see what happens...those northern disturbances often wreak havoc during these La Ninas.

I thought we had gotten into better sampling beginning with 0z last night.

[atownwxwatcher]

18 Z NOGAPS

[EasternLI]

In response to someone's post...yes...the northern disturbance should be better sampled tonight so we'll see what happens...those northern disturbances often wreak havoc during these La Ninas.

LOL... Thanks, I know that has been an issue in the past

[eduggs]

No you are so very wrong--it really is pathetic and silly. The amplification and deeper trough would have resulted in a slower developing and ejecting eventual wave--and this was why it was needed in the first place--so the western wave would have time to eject east ahead of the trough for a full phase.

My point is relatively simple. I was looking for a deeper trof digging further south into the central US. Yes this COULD allow the southern wave to slide underneath to the upstream flank and amplify the whole structure. Regardless, this is the ingredient for significant storm formation that I was keying on.

But a good phase by itself was not and is not sufficient. Of course they are related in terms of storm development, but they are also distinct meteorological concepts. Several of the NAM runs showed a good phase. But none of them showed a sufficiently deep trof. That's why I a few days ago I expressed my preference to tone down the adjectives and gear up for a moderate stor

[IsentropicLift]

Anybody that thinks that this system is set in stone already hasn't been paying much attention to the model trends this season so far. I understand what Baraclonic Instability was saying earlier about what the WV images are showing however with the 12/26 event if everyone remembers correctly, what kept everyone interested after the euro lost the storm was that the northern stream kept diving further and further south with each model run and eventually phased. I'm not saying that this is going to be the same scenario as the synoptic setups are quite different but it just goes to show how slight differences with the northern stream can be the difference between a weak clipper and a coastal bomb.

[EasternLI]

Boy it's COLD on the east end i wonder why that hasn't worked right since you joined....

LOL...Yep, it seems to have gone down right when I started using it.

[baroclinic_instability]

That just shows how bad these models are, ridiculous changes in s/w phasing for a 12 hour margin...one looks as if it's headed to a full-blown Nor'easter whereas the latter is a glancing blow at most.

Not bad--but the nature of the forecast and the intricacies involved with the flow pattern. East Coast coastal threats, especially when multiple waves are involved, have a tendency to make any model look "bad". I guess think of it as this--where were we 50 years ago when there was NO numerical guidance? Far worse off I can guarantee.

[jasonli18t]

LOL...Yep, it seems to have gone down right when I started using it.

KFOK is down, if you change it to KOKX i bet it would work.

[SnowGoose69]

I thought we had gotten into better sampling beginning with 0z last night.

You would think so but the models seemed to be later picking up the northern system on the 12/26 storm, this morning it was still over the southern part of the NW Territories, that is too far north if you ask me to be properly sampled...even tonight it may not yet be fully into the U.S.

[baroclinic_instability]

My point is relatively simple. I was looking for a deeper trof digging further south into the central US. Yes this COULD allow the southern wave to slide underneath to the upstream flank and amplify the whole structure. Regardless, this is the ingredient for significant storm formation that I was keying on.

But a good phase by itself was not and is not sufficient. Of course they are related in terms of storm development, but they are also distinct meteorological concepts. Several of the NAM runs showed a good phase. But none of them showed a sufficiently deep trof. That's why I a few days ago I expressed my preference to tone down the adjectives and gear up for a moderate stor

You claimed "misdiagnoses" by the meteorologists while you ramble on with a completely incorrect diagnoses of your own.

That said, you have a good understanding of basic meteorology--but you really are not giving the intricacies in this setup due diligence as those tiny intricacies can have massive final results when one is discussing non-linear cyclogenesis.

[baroclinic_instability]

You would think so but the models seemed to be later picking up the northern system on the 12/26 storm, this morning it was still over the southern part of the NW Territories, that is too far north if you ask me to be properly sampled...even tonight it may not yet be fully into the U.S.

Based on your comments I assume you see a threat for the 1993 analog to occur? I am not disagreeing, I am just wondering what you are thinking in terms of the threat potential.

[eduggs]

Yup, this is pretty much what I was saying. I don't understand how there can be much of an argument. I posted the image on the last page but here it is again for reference. It's not even close, and it's pretty cut and dry (no pun intended) as to why the NAM is less amplified, doesn't have the cyclogenesis nearer to the coast, and is much later to develop the cyclone.

And that's a perfect illustration of why I favored areas to our NE and set a modest bar for local snowfall.

With the synoptic features as they are, there's just not a lot of room or time for us - even on the 06z.

[earthlight]

And that's a perfect illustration of why I favored areas to our NE and set a modest bar for local snowfall.

With the synoptic features as they are, there's just not a lot of room or time for us - even on the 06z.

It's a perfect illustration as to why the phasing is a major component in getting the storm to develop faster and further southwest, which you argued earlier was not an issue at all. The 06z NAM bufkit gave many areas 10 or more inches. That's a significant snowstorm...so I don't really get why you're completely backing away from that original argument.

[EasternLI]

KFOK is down, if you change it to KOKX i bet it would work.

Thx....I think I fixed it

[earthlight]

KFOK is down, if you change it to KOKX i bet it would work.

Oh, the NWS and their underlying sexual innuendos.

[eduggs]

How can you say that the northern stream wasn't forecast by any model to dive that far south? The NAM had 510dm heights in the Central Great Lakes and a significant shortwave with impressive height falls over the Mississippi Valley! What kind of world are you living in? Again, you're ignoring the simple facts. You're saying that the NAM bombed the low out too far northeast. The NAM for four or more runs had a sub 988mb low pressure system off the NJ Coast along the baroclinic zone. What else are you looking for here? A Dec 26 978mb low pressure 50 miles south of Montauk Point? Sorry, that's fantasy land man.

Listen, you're already backing away from your main argument which was that the phase meant nothing. That was incorrect. Now you're reverting to calling out one of the best forecasters on the board for his inability to demonstrate a perception for the possibility of a storm failure. The guy posted probably 10 or more times that the odds were stacked against us.

It seems to be that you haven't been around the past few days, have missed some significant discussion and have missed some key operational guidance. I suggest you peruse the threads before making such bold statements. I'm all for analytical discussion, but come on man. This is a pretty weak argument if you ask me.

Go back and look at the mid-levels on the NAM and you'll see what I mean. Or even 700mb! Dec 26 is NOT COMPARABLE. I'm actually quite surprised that you would bring that up. Surface pressure by itself is not very telling. The NAM runs you reference had a strong frontside hit of overrunning and quickly over. But the mid-levels were immature until the storm moved to higher latitudes. We just weren't in a favorable geographical location for a big hit, regardless of what the NAM QPF was printing out.

My main point was that our geographical location with respect to the synoptic features was the limiting factor. And I made this point several days ago. A s/w on the upstream side of a longwave trof with amplify the entire structure and set off a self perpetuating cyclone development process. But you have to be in the right spot to take advantage of this, and even in the best case I thought we'd be on the fringe. That's why I downplayed the importance of the phase and emphasized our location with respect to the position and amplitude of the trof.

[jasonli18t]

Oh, the NWS and their underlying sexual innuendos.

mount holly...and then who?

[earthlight]

Go back and look at the mid-levels on the NAM and you'll see what I mean. Or even 700mb! Dec 26 is NOT COMPARABLE. I'm actually quite surprised that you would bring that up. Surface pressure by itself is not very telling. The NAM runs you reference had a strong frontside hit of overrunning and quickly over. But the mid-levels were immature until the storm moved to higher latitudes. We just weren't in a favorable geographical location for a big hit, regardless of what the NAM QPF was printing out.

My main point was that our geographical location with respect to the synoptic features was the limiting factor. And I made this point several days ago. A s/w on the upstream side of a longwave trof with amplify the entire structure and set off a self perpetuating cyclone development process. But you have to be in the right spot to take advantage of this, and even in the best case I thought we'd be on the fringe. That's why I downplayed the important of the phase and emphasized our location with respect to the position and amplitude of the trof.

Lol, I brought up December 26th as something that you were comparing it to..because you keep saying that the storm was poor and underdeveloped. What I was saying was that not every storm was going to be like that.

Again, I think you're just going right over the top of the argument. The point was that if the phase occurred earlier and in a better position, we could get a significant snowstorm as precipitation developed on the northwest side of a rapidly deepening surface low. The models aren't stupid. The NAM was producing that type of precipitation because when you have those type of upper air dynamics you're going to get heavy precipitation regardless of if it's a well developed cold conveyor belt with closed H7 and H85 lows. Of course our location wasn't perfect. But to say that the phase wasn't a major player in getting more rapid development is rather silly.

[famartin]

Oh, the NWS and their underlying sexual innuendos.

I vaguely recall that KFOK was reference to the AFB that used to be there. I think the OK in KOKX is from Brookhaven... and the NWS just likes to stick X's onto identifiers for radar sites, so that's where the X came from.

[Thunder Road]

Oh, the NWS and their underlying sexual innuendos.

don't forget KDIX

[_AR_]

Enjoy your rain, nyc:

12Z CRAS still showing a bomb. lol.

Australian looks like a hit too:

[eduggs]

You claimed "misdiagnoses" by the meteorologists while you ramble on with a completely incorrect diagnoses of your own.

That said, you have a good understanding of basic meteorology--but you really are not giving the intricacies in this setup due diligence as those tiny intricacies can have massive final results when one is discussing non-linear cyclogenesis.

I didn't mean to be diagnosing anything. And that's probably the wrong word I used. I just think the difference between a perfect and imperfect phase in this case had relatively minor implications because of the larger synoptic features and our geographical location. That's not to say this is true in every case. I thought the NAM went overboard in illustrating the upper end of potential by printing out too much QPF over a short period. And I get frustrated when I read a conclusion that things went down the ****ter because it "didn't phase." In fact we have a partial phase, it will snow, and an ocean gale with form eventually anyway.

You're probably right though. I didn't focus on the intricacies because I didn't think we ever got to that point. At no point did I think subtle shortwave interactions could modify the height field sufficiently. I never saw this as anything but a glancing blow. And yes I do believe you can get a glancing 8" of snow.

[SnowGoose69]

Enjoy your rain, nyc:

12Z CRAS still showing a bomb. lol.

Australian looks like a hit too:

I'd prefer to see the CRAS more amplified to be honest...the fact its on the coast likely means any track inside the benchmark is much less likely...of course the NOGAPS is inside the benchmark so who the hell knows what to believe.