Novie is near, the first un-official month of SNE winter!

[Typhoon Tip]

this is like the 4th of 5th time i've seen this happen in recent decade... 

the MJO prog seems to lead the development of tropical disturbances in the western Pacific. 

that may be entirely understood already - not 'as' privy to the science as such - but... the MJO has very recently shown a much more coherent signal than it has in recent weeks, with a discerned maturation of wave strength pressing thru the Phase 6 and deep into the Phase 7 wave space at moderate strength, going through this next week to 10 days. 

not a two days after that signal comes into focus ... there are two new Invests over the west Pacific tropics.  i have a hunch... one or two of these disturbance will development and turn into the westerlies, because:

note, the Phase 7-8 is typically correlated to -WPO and eventually that translates down stream to encourage the breadth of the northern Pacific circulation medium into the AB phase ... --> -EPO .. with modality in the PNA.   

EPO and PNA typically negatively correlate ...which has to do with natural/stablizing R-wave spacing ... tough to run a +PNA and -EPO without some sort of exotically amplified paradigm that features an utter and true polar split in the vortex with two/multi distinct nodal construct (with embedded L/W's notwithstanding..) umbrella draped over the hemisphere... etc..  we should naturally see the -AO in such a paradigm.  

anyway, but as the PNA modulates and then typically the EPO ends up negative when the MJO is in these left side (Wheeler) waves spaces.  

So, in a very simple statement: tropical forcing might be about to positive/constructively interfere; the Pacific may move toward more of an AB phase, which is cold for North America.  this is spanning ten days ... maybe two weeks.  could be step wise down; could be hold out then crash scenario too..

it's formulative for now ..we'll see how it evolves going forward.  but the erstwhile +PNA/ -AO / -NAO discussed hasn't really wavered in the GEFs derivatives so ... it would/could/intuitively be interesting should then these other teleconnectors shake hands up underneath.  hmm... -polar arc with a tropical forcing showing up would proooobably put the coup de gras on the warm signal in the nations midriff and play a role in giving winter's arrival a a real boost everywhere else as we get closer to Novie 10 -15. 

I'm still seeing an insistence for the pattern change around the 10th coming from the GEFs ... but the Euro may yet push that off until the 15th. nevertheless, still confident that November does not end like it is beginning  whether the 10 or 20th is truer.

[CoastalWx]

We may see the beginnings of long range hinting at maritime tropical forcing and perhaps dateline ridging. I'm looking beyond mid Novie here. Using some of Mike Ventrice's stuff and EC ensemble, you can see it happening.  I think using velocity potential at 200mb is better than typical MJO diagrams as the OLR and westerly momentum can be skewed by tropical systems. VP at 200mb shows where we have favorable forcing for convection and seems to be a better proxy for MJO type convection.

That would be nice because if it does lead to more -PNA....perhaps it gets Canada back into a colder and snowier look as they will blowtorch any snow they have over the next two weeks.  I care more about getting the source region in place then a renegade early season event from a +PNA driven pattern.

[CoastalWx]

The GEFS stuff sure looks nice and in the meantime, maybe we can get some sort of +PNA induced event should that be right. I'm a little unsure because the model bias so far as been to limit the GOAK low influence. If one looks at previous 11-15 day forecasts and then roll forward to 6-10day and 1-5 day...you can see that. Of course that can change, but I'm somehwat reluctant on the magnitude of the 6z GEFS ensemble look.

[OceanStWx]

13 minutes ago, CoastalWx said:

We may see the beginnings of long range hinting at maritime tropical forcing and perhaps dateline ridging. I'm looking beyond mid Novie here. Using some of Mike Ventrice's stuff and EC ensemble, you can see it happening.  I think using velocity potential at 200mb is better than typical MJO diagrams as the OLR and westerly momentum can be skewed by tropical systems. VP at 200mb shows where we have favorable forcing for convection and seems to be a better proxy for MJO type convection.

That would be nice because if it does lead to more -PNA....perhaps it gets Canada back into a colder and snowier look as they will blowtorch any snow they have over the next two weeks.  I care more about getting the source region in place then a renegade early season event from a +PNA driven pattern.

Obviously playing with fire a bit, but we can do just fine with a -PNA if the cold air is around too.

[ORH_wxman]

1 minute ago, OceanStWx said:

Obviously playing with fire a bit, but we can do just fine with a -PNA if the cold air is around too.

 

Some of our best early season patterns have come during a -PNA...Dec 2007, Dec 2008, Dec 1981, Dec 1970, Dec 1961.

[CoastalWx]

1 minute ago, OceanStWx said:

Obviously playing with fire a bit, but we can do just fine with a -PNA if the cold air is around too.

Definitely. Would allow for a gradient look if it goes well. I see some going for a warm December with more of a CONUS torch so we shall see. Pretty remarkable warmth over the next two weeks with the exception of the northeast. That is the true definition of a blowtorch.  I think regardless of what happens, seems like a window between mid month and T-day for something to occur if te ensembles are right. 

[CoastalWx]

31.1" for December 1970 at the Hingham COOP. How's that for a coastal location.    31.5" for Dec 2008.

[Damage In Tolland]

Still think better than avg chance of white T-giving this year

[OceanStWx]

One of our summer interns did a local study on the NAO and PNA regarding precip and temps. Not surprisingly he found +PNA and -NAO was a cold signal. But -PNA was the high precip signal.

We know for the most part our snowfall is better correlated to QPF than temps, because chances are it'll be cold enough to snow around here if we get the precip.

Conversely, the +PNA/-NAO combo was a negative QPF signal. Sure that pattern can produce a whopper, but those tend to be few a far between.

[OceanStWx]

15 minutes ago, CoastalWx said:

31.1" for December 1970 at the Hingham COOP. How's that for a coastal location.    31.5" for Dec 2008.

PWM 38.8" in 2007.

[ORH_wxman]

3 minutes ago, OceanStWx said:

One of our summer interns did a local study on the NAO and PNA regarding precip and temps. Not surprisingly he found +PNA and -NAO was a cold signal. But -PNA was the high precip signal.

We know for the most part our snowfall is better correlated to QPF than temps, because chances are it'll be cold enough to snow around here if we get the precip.

Conversely, the +PNA/-NAO combo was a negative QPF signal. Sure that pattern can produce a whopper, but those tend to be few a far between.

 

Yeah the +PNA/-NAO is great for sustained cold and a potential big storm, but you also can get long stretches of dry weather with that pattern. I've always been a pretty big fan of the -PNA/-NAO pattern...some of our best snowy stretches have come during that.

[OceanStWx]

3 minutes ago, ORH_wxman said:

Yeah the +PNA/-NAO is great for sustained cold and a potential big storm, but you also can get long stretches of dry weather with that pattern. I've always been a pretty big fan of the -PNA/-NAO pattern...some of our best snowy stretches have come during that.

-NAO/+PNA and powderfreak is getting ready to puff puff pass.

[CoastalWx]

Not hard to see why a -PNA/-NAO deliver. You get the colder air trying to move south in the Plains with part of it oozing into New England. SE ridge as a response to a -PNA, but the -NAO says hold on and tries to keep the SE ridge from burgeoning too far north and locks in cold over New England.  I wouldn't mind seeing that. I feel like this won't be one of those December's but who knows. 

[jbenedet]

1 hour ago, OceanStWx said:

One of our summer interns did a local study on the NAO and PNA regarding precip and temps. Not surprisingly he found +PNA and -NAO was a cold signal. But -PNA was the high precip signal.

We know for the most part our snowfall is better correlated to QPF than temps, because chances are it'll be cold enough to snow around here if we get the precip.

Conversely, the +PNA/-NAO combo was a negative QPF signal. Sure that pattern can produce a whopper, but those tend to be few a far between.

Interesting. 

I see it was a local study--how local is local?

I can definitely see -NAO -PNA working out well for NNE in general, but I believe that combo would give SNE and even parts of CNE warmer/less snowy winters. Is there any sort of cut-off/dividing line we can infer based on the study?

[qr7121]

2 hours ago, Typhoon Tip said:

this is like the 4th of 5th time i've seen this happen in recent decade... 

the MJO prog seems to lead the development of tropical disturbances in the western Pacific. 

that may be entirely understood already - not 'as' privy to the science as such - but... the MJO has very recently shown a much more coherent signal than it has in recent weeks, with a discerned maturation of wave strength pressing thru the Phase 6 and deep into the Phase 7 wave space at moderate strength, going through this next week to 10 days. 

not a two days after that signal comes into focus ... there are two new Invests over the west Pacific tropics.  i have a hunch... one or two of these disturbance will development and turn into the westerlies, because:

note, the Phase 7-8 is typically correlated to -WPO and eventually that translates down stream to encourage the breadth of the northern Pacific circulation medium into the AB phase ... --> -EPO .. with modality in the PNA.   

EPO and PNA typically negatively correlate ...which has to do with natural/stablizing R-wave spacing ... tough to run a +PNA and -EPO without some sort of exotically amplified paradigm that features an utter and true polar split in the vortex with two/multi distinct nodal construct (with embedded L/W's notwithstanding..) umbrella draped over the hemisphere... etc..  we should naturally see the -AO in such a paradigm.  

anyway, but as the PNA modulates and then typically the EPO ends up negative when the MJO is in these left side (Wheeler) waves spaces.  

So, in a very simple statement: tropical forcing might be about to positive/constructively interfere; the Pacific may move toward more of an AB phase, which is cold for North America.  this is spanning ten days ... maybe two weeks.  could be step wise down; could be hold out then crash scenario too..

it's formulative for now ..we'll see how it evolves going forward.  but the erstwhile +PNA/ -AO / -NAO discussed hasn't really wavered in the GEFs derivatives so ... it would/could/intuitively be interesting should then these other teleconnectors shake hands up underneath.  hmm... -polar arc with a tropical forcing showing up would proooobably put the coup de gras on the warm signal in the nations midriff and play a role in giving winter's arrival a a real boost everywhere else as we get closer to Novie 10 -15. 

I'm still seeing an insistence for the pattern change around the 10th coming from the GEFs ... but the Euro may yet push that off until the 15th. nevertheless, still confident that November does not end like it is beginning  whether the 10 or 20th is truer.

mark your calendars... 11/15-12/15 = cold and snowy in general, threat of a HECS ~11/25. 

[qr7121]

PNA/NAO etc all irrelevant acronyms post-sea ice collapse... this is only one yr difference, compared to all others we have completely fallen off the wagon

 

yet we now have the highest or second highest snowcover on record... easily two weeks ahead of schedule...

[Typhoon Tip]

2 hours ago, CoastalWx said:

We may see the beginnings of long range hinting at maritime tropical forcing and perhaps dateline ridging. I'm looking beyond mid Novie here. Using some of Mike Ventrice's stuff and EC ensemble, you can see it happening.  I think using velocity potential at 200mb is better than typical MJO diagrams as the OLR and westerly momentum can be skewed by tropical systems. VP at 200mb shows where we have favorable forcing for convection and seems to be a better proxy for MJO type convection.

That would be nice because if it does lead to more -PNA....perhaps it gets Canada back into a colder and snowier look as they will blowtorch any snow they have over the next two weeks.  I care more about getting the source region in place then a renegade early season event from a +PNA driven pattern.

yeah .. .what i meant specifically is, 'is it possible' the advent of Investing and TCs emerging where the MJO progs lead (or seems to sometimes often enough..) could be causally related, while ... heh, not necessarily related to each other. 

meaning, what ever it is that triggers the models to start showing an MJO modality, those parameters "might" also encourage the TC stuff (thus, the wave space correlates).  Just a thought.. 

like, recently the MJO's been spiraling around on the right hand side and doing so at almost incoherent intensities ...  but suddenly over the last two or three days, the Wheeler picks up a concerted march and strengthening behavior straight to the boundary of phase 7/8 and beyond.  I don't think it is a coincidence (personally) that there are suddenly three Invest showing up to the playground.  

whether they relate, or is all mere coincidence aside... agreed, in the minimal it all might flag tropical forcing getting into supportive role here over the next week to two weeks.  we'll see.

as far as TC's them selves .. i am frankly not hugely versed in the whole recurve theory, though what i have read of it doesn't seem like a big leap of logic and intellect.  you dump a ton of latent heat into the westerlies, wave mechanics will distribute it accordingly ...more like surprising it wasn't discovered earlier.  now that we are squarely into colder migration of heights (hemispheric) s, the trigger/gradient thresholds are crossed enough such that coherence on pattern forcing down stream for TC recurve is more attainable.  i think of TCs as a transient impact on the totality of the flow construction tho - being absorbed in negative interference and adding in positive.. kind of like just below the MJO's contribution, where the MJO also needs to arrive into a positive interference its self in order to demonstrate influence on the flow.   

 

[qr7121]

i do not think Canada will lose its snowpack... maybe a little bit but the +depth anomalies are significant and models always underestimate cold in Quebec, which is the most important source region for the NE. in fact i would suspect that even with the +anomalies, we see snowcover continue deepening over Quebec.

[ORH_wxman]

37 minutes ago, qr7121 said:

PNA/NAO etc all irrelevant acronyms post-sea ice collapse... this is only one yr difference, compared to all others we have completely fallen off the wagon

 

yet we now have the highest or second highest snowcover on record... easily two weeks ahead of schedule...

 

I don't see how they are irrelevant because of sea ice decline. They are still representing the longwave pattern which is what matters.

[OceanStWx]

42 minutes ago, jbenedet said:

Interesting. 

I see it was a local study--how local is local?

I can definitely see -NAO -PNA working out well for NNE in general, but I believe that combo would give SNE and even parts of CNE warmer/less snowy winters. Is there any sort of cut-off/dividing line we can infer based on the study?

Pretty sure it was was the 4 "New England" offices. So just CAR, GYX, BOX, and BTV, and just ignoring the New York WFOs to keep it simple.

What you say is why I mentioned playing with fire. Yeah, it's a gradient pattern, but some years that gradient is down by NYC and other years it's by CON. Overall though, I think New England would rather take the QPF and bank on temps eventually getting cold enough for snow, than take the temps and hope the QPF eventually comes around.  

[Typhoon Tip]

I'm not sure i see how sea ice logically follows?  

[qr7121]

1 minute ago, ORH_wxman said:

 

I don't see how they are irrelevant because of sea ice decline. They are still representing the longwave pattern which is what matters.

i disagree. they are arbitrary numbers calculated from arbitrary boxes. recently we have seen no real correlation between -NAO/+NAO and sensible wx in the NE, and the same has happened to the PNA (IMO). 

they do not represent a longwave pattern, instead they show a human-derived number that may or may not have meaning to our sensible weather. the broiling Arctic Ocean is significantly more important and has now overwhelmed any remote usefulness of those "indices". now they are just meaningless acronyms. 

[qr7121]

3 minutes ago, Typhoon Tip said:

I'm not sure i see how sea ice logically follows?  

...areas not covered by sea ice allow significantly more heat/moisture far deeper into the Arctic vs previous years and latent heat release during winter (from the millions of extra KM2 of open water this yr) results in 500mb blocking. blocking is not random, it is a symptom of the dying NPole ice cap and an inability for the pole to resolve heat passing overhead. 

since SSTs up north are well beyond the previous record this year, and we are already seeing NHEM snowcover blow past (or at least approach) previous all-time records, i think rolling the current look forward results in record blocking across both the Beaufort/Chukchi as well as the Barents/Kara... i.e. the two most favored regions to result in additional NHEM +++snowcover anomalies. 

[OceanStWx]

Just now, qr7121 said:

i disagree. they are arbitrary numbers calculated from arbitrary boxes. recently we have seen no real correlation between -NAO/+NAO and sensible wx in the NE, and the same has happened to the PNA (IMO). 

they do not represent a longwave pattern, instead they show a human-derived number that may or may not have meaning to our sensible weather. the broiling Arctic Ocean is significantly more important and has now overwhelmed any remote usefulness of those "indices". now they are just meaningless acronyms. 

I literally just cited how our New England study showed the PNA impact on our sensible weather. It is a large driver of cool season QPF, not to mention temperature regimes. Likewise NAO, albeit a weaker signal.

They are numbers calculated from boxes, but I disagree that they are arbitrary. 

[qr7121]

1 minute ago, OceanStWx said:

I literally just cited how our New England study showed the PNA impact on our sensible weather. It is a large driver of cool season QPF, not to mention temperature regimes. Likewise NAO, albeit a weaker signal.

They are numbers calculated from boxes, but I disagree that they are arbitrary. 

i think you are correct in that they held more value in previous years; what i am saying is that we have broken our old climate and now that the Arctic is +6C compared to 20-30-yrs ago, the heat up north overwhelms any possible signal that can be derived from those boxes. i would posit this shift happened around 2010 and is now worsening on an annual basis. 

so your data is not necessarily *bad* or incorrect -- it is just no longer applicable in a world that is so much warmer vs. only 10-20 yrs ago, esp. up N

[OceanStWx]

1 minute ago, qr7121 said:

i think you are correct in that they held more value in previous years; what i am saying is that we have broken our old climate and now that the Arctic is +6C compared to 20-30-yrs ago, the heat up north overwhelms any possible signal that can be derived from those boxes. i would posit this shift happened around 2010 and is now worsening on an annual basis. 

so your data is not necessarily *bad* or incorrect -- it is just no longer applicable in a world that is so much warmer vs. only 10-20 yrs ago, esp. up N

There is far more that goes into the global pattern besides Arctic circulations. The Pacific jet is a huge driver, and it has more input than just Siberian snow or Arctic ridging.

I think you are overstating your point.

[ORH_wxman]

2 minutes ago, qr7121 said:

i think you are correct in that they held more value in previous years; what i am saying is that we have broken our old climate and now that the Arctic is +6C compared to 20-30-yrs ago, the heat up north overwhelms any possible signal that can be derived from those boxes. i would posit this shift happened around 2010 and is now worsening on an annual basis. 

so your data is not necessarily *bad* or incorrect -- it is just no longer applicable in a world that is so much warmer vs. only 10-20 yrs ago, esp. up N

 

You don't have any empirical evidence of this. The EPO is probably one of the most important indices for cold in the central/eastern U.S....and it absolutely drove the pattern in 2013-2014 and 2014-2015. Just because the NAO was positive those years doesn't mean it isn't important anymore. It was overwhelmed by a staunch EPO pattern...and it wasn't a new phenomenon...go look at years like 1960-1961 and 1993-1994.

[qr7121]

1 minute ago, ORH_wxman said:

 

You don't have any empirical evidence of this. The EPO is probably one of the most important indices for cold in the central/eastern U.S....and it absolutely drove the pattern in 2013-2014 and 2014-2015. Just because the NAO was positive those years doesn't mean it isn't important anymore. It was overwhelmed by a staunch EPO pattern...and it wasn't a new phenomenon...go look at years like 1960-1961 and 1993-1994.

what is the EPO? why did it drive the pattern? do you see what i am saying?

the EPO is symptomatic of something larger at work (Hadley Cell interaction with weakened/split polar vortex + open water up north)... it is *not* a driver in itself, rather an index based on arbitrary calculations. it is important to identify the symptoms behind the patterns instead of the results within a bounded area... 

[qr7121]

8 minutes ago, OceanStWx said:

There is far more that goes into the global pattern besides Arctic circulations. The Pacific jet is a huge driver, and it has more input than just Siberian snow or Arctic ridging.

I think you are overstating your point.

i would posit that the Pac jet is also largely dictated by Arctic sea ice and resulting snowfalls across the continents... in our current case we have a very warm Arctic surrounded by some record-cold air in Siberia etc right now. the gradient (very cold continents + relatively warm sea above and to the east) results in a very strong jet stream in certain areas, specifically the NPAC at the moment... obviously the tropics are also involved in this, but i highly suspect that the relationship between sea ice + snowcover is the primary driver behind the strength of the Pacific jet

[ORH_wxman]

2 minutes ago, qr7121 said:

what is the EPO? why did it drive the pattern? do you see what i am saying?

the EPO is symptomatic of something larger at work (Hadley Cell interaction with weakened/split polar vortex + open water up north)... it is *not* a driver in itself, rather an index based on arbitrary calculations. it is important to identify the symptoms behind the patterns instead of the results within a bounded area... 

 

EPO is just describing the region up by Alaska/Bering Straight...I'm not sure what exactly you are arguing. When there is a large ridge over Alaska, you typically get very cold weather in the central and eastern U.S. We saw this happen in 2013-2014 and 2014-2015. The decline of sea ice didn't change that fact. When it gets replaced by a vortex, we get a torch like 2011-2012 and 2015-2016. The loss of sea ice still didn't change this fact.

 

Now if you are arguing that a ridge or trough might become more likely in a certain region due to the loss of sea ice, that is a different debate than saying the index numbers are completely irrelevant. They still represent a real pattern.