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March 2-4th ... first -NAO anchored storm perhaps in years

Typhoon Tip

By Typhoon Tip,
in New England

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Typhoon Tip

Typhoon Tip

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There's larger scaled problems with the "true stall" scenario .. hemispheric in scope/caused really.   Although, slow movement is still underway, that may in part be the mechanics of deepening during closing off tending to temporarily countermand the surrounding steering .. 

Said steering was thought to be less coherent during this time as the NAO blocking's retrogression approached the Maritime regions, understandably. However, that is/was not the case.  That part has both failed (partially) but is also not normal for -3 or -4 SD NAOs that are west-based...  East based? That may be more likely ...  but with west-based, we should be maximizing the breakdown of the normal west to east resonance of the atmosphere - hence the term "retrograde." Thus, as system evolutions of this ilk, as history has shown, would stall.

So what's up?    ...Well, I'm looking at the Euro and GFS' two 00z and 06z cycles and they all expose that the SE ridge is still very much intact. There's been conjecture that the SE ridge would decay as this NAO evolved and that may certainly be true (or not...). Regardless, as of this day, it is there supplying a progressive force on this entire system's construct. 

 

seridge.thumb.jpg.ddf60ba7cddd7a575ac8dee7684a56c8.jpg

It's merely being compressed by this things migration over the top... Here's the problem, in terms of wave mechanics and offsetting to the stall is that it speeds up the flow in between and that's the source of the partial if not total breakdown in stall/retrograde capability. You can't really stall a deep layer vortex ivo  ISP when you have large scale planetary wave mechanics literally pushing this thing along from the south, such that these two annotations above more than merely suggest.  I used to refer to this as the "Miami rule" back in the day... and it has to do with heights and or balanced geostrophic winds over that raob site.  If the heights are greater than ~ 582, and/or the wind is moving fast than ~ 35 kts, that means that whether the model "looks" like it or not, there is in fact some sort of negating ridge tendency that will offset and/or perturb waves as they move through the eastern North American middle latitudes.  This stung the forecast community back in March of 2001 ... when it caused that event/deep anomaly to rather uncharacteristically foist too quickly east to involve the M/A region as much as it appeared would be the case as little as three days prior to that event.   

I also suspect it has an indirect cause to why we have the two main global models indicated < 525 DAM core heights passing under LI with snow having problems on the N wall of that container.  That depth and liquid do not usually happen together; I believe the SE ridge and perhaps more importantly ...  the general -PNAP flow that this thing is evolving through sort of tore up the lower troposphere and made for an unusual thermal layout relative to this sort of thing's evolution.  This whole -NAO period is really fraught with nuances..  At the end of all this and 140 whatever pages of this thread, I think we simply are at war between the Pacific and the N. Atlantic, and this system's idiosyncrasies are a direct result.  

 

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40/70 Benchmark

40/70 Benchmark

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33 minutes ago, Typhoon Tip said:

There's larger scaled problems with the "true stall" scenario .. hemispheric in scope/caused really.   Although, slow movement is still underway, that may in part be the mechanics of deepening during closing off tending to temporarily countermand the surrounding steering .. 

Said steering was thought to be less coherent during this time as the NAO blocking's retrogression approached the Maritime regions, understandably. However, that is/was not the case.  That part has both failed (partially) but is also not normal for -3 or -4 SD NAOs that are west-based...  East based? That may be more likely ...  but with west-based, we should be maximizing the breakdown of the normal west to east resonance of the atmosphere - hence the term "retrograde." Thus, as system evolutions of this ilk, as history has shown, would stall.

So what's up?    ...Well, I'm looking at the Euro and GFS' two 00z and 06z cycles and they all expose that the SE ridge is still very much intact. There's been conjecture that the SE ridge would decay as this NAO evolved and that may certainly be true (or not...). Regardless, as of this day, it is there supplying a progressive force on this entire system's construct. 

 

seridge.thumb.jpg.ddf60ba7cddd7a575ac8dee7684a56c8.jpg

It's merely being compressed by this things migration over the top... Here's the problem, in terms of wave mechanics and offsetting to the stall is that it speeds up the flow in between and that's the source of the partial if not total breakdown in stall/retrograde capability. You can't really stall a deep layer vortex ivo  ISP when you have large scale planetary wave mechanics literally pushing this thing along from the south, such that these two annotations above more than merely suggest.  I used to refer to this as the "Miami rule" back in the day... and it has to do with heights and or balanced geostrophic winds over that raob site.  If the heights are greater than ~ 582, and/or the wind is moving fast than ~ 35 kts, that means that whether the model "looks" like it or not, there is in fact some sort of negating ridge tendency that will offset and/or perturb waves as they move through the eastern North American middle latitudes.  This stung the forecast community back in March of 2001 ... when it caused that event/deep anomaly to rather uncharacteristically foist too quickly east to involve the M/A region as much as it appeared would be the case as little as three days prior to that event.   

I also suspect it has an indirect cause to why we have the two main global models indicated < 525 DAM core heights passing under LI with snow having problems on the N wall of that container.  That depth and liquid do not usually happen together; I believe the SE ridge and perhaps more importantly ...  the general -PNAP flow that this thing is evolving through sort of tore up the lower troposphere and made for an unusual thermal layout relative to this sort of thing's evolution.  This whole -NAO period is really fraught with nuances..  At the end of all this and 140 whatever pages of this thread, I think we simply are at war between the Pacific and the N. Atlantic, and this system's idiosyncrasies are a direct result.  

 

John, great post....I missed the part about the RNA mitigating the stall potential, but was all over the other aspects of it.

Invaluable learning experience, as I couldn't figure out why it was remaning this progressive in light of the full capture..figured it involved more than vorticity distribution around the ULL. Be that as it may, it still isn't exactly flying along...as was the case with the March 2001 event.

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40/70 Benchmark

40/70 Benchmark

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5 minutes ago, CoastalWx said:

The NAM fronto fields are definitely north of 6z late today. That may bode well (hopefully) for areas north of the pike once we drop the torch just aloft.  Something to watch would be GYX radar and comparing the hose off the Gulf of Maine to model output.

I've always thought south of PSM is game.

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Typhoon Tip

Typhoon Tip

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12 minutes ago, RUNNAWAYICEBERG said:

Yea, this deff gets squeezed between block and se ridge like a bad pimple...once it gets into the atlantic a bit there’s your stall. 

Exactly ... not to drop names, but.. when I interned with Harv ...back in the last Century ... he clued me onto the notion of "where is the actual long-wave" - which I suspect is his own way of addressing this stuff.  I recall vividly we were discussing it when we were going over charts ...and trying to assess where a system affecting our region would probably get to it's strongest amplitude...etc..etc.. But, this isn't a full latitude system - that may be the first clue. The lower latitude wave trough configuration is really sort of out of sync with the stream this system is embedded in... fascinating. 

In this situation it is interesting,  ..we get to that amplitude probably as this is drifting SE this evening... but, the actual real "stall" lat/lons are as you suggest, somewhere meandering out there NE of Bermuda or something.  

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Typhoon Tip

Typhoon Tip

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14 minutes ago, 40/70 Benchmark said:

John, great post....I missed the part about the RNA mitigating the stall potential, but was all over the other aspects of it.

Invaluable learning experience, as I couldn't figure out why it was remaning this progressive in light of the full capture..figured it involved more than vorticity distribution around the ULL. Be that as it may, it still isn't exactly flying along...as was the case with the March 2001 event.

Yeah thanks Ray... honestly I was taken aback a little too, but ... mm, I started looking at this from a fresher point of view this morning  ... after having thrown hands and deciding pretty definitively that I didn't care anymore and was sick of this one.  Sometimes a bit of disconnect serves for a better perspective. It dawns on me...wait a second... that is really kind of wrong. 

Oh well.. If we are winter enthusiast... we have other opportunities at least through mid month - I think... I think everyone involved in this did an outstanding job, yourself included... I wouldn't really grade anyone poorly based on 12 hours worth of failed "stalling" or... mix line that's 50 miles one way or the other.  This was a beast both for it's attributes, but for coming along with so many nuances... We collectively recognized this time slot of interest ... what, two weeks ago? 

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TalcottWx

TalcottWx

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4 hours ago, JC-CT said:

Remember that time when you told me this storm doesn't work like that? Maybe you should just wait and see what happens. 


It all comes down to precip intensity and well as some banding which will result in precip flipping between rain and
snow and vice versa.

https://forecast.weather.gov/product.php?site=NWS&issuedby=BOX&product=AFD&format=CI&version=1&glossary=1&highlight=off

This is exactly what I argued AGAINST what you were saying but OK 

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JC-CT

JC-CT

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Posted
7 minutes ago, sbos_wx said:

This is not how this storm works 

1 hour ago, tavwtby said:

It's flipping back and forth, about an inch of glop OTG

Oh ok, you really are just a dope. Not just this, but doing things like chastising posters for not looking at models and then admitting 10 minutes later that you haven't looked at a model. It's embarrassing.

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