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First half of February...another pattern shift?


ORH_wxman

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This all starts around 2/2? Or later?

More like 2/5 or later...but there is a shot at a transition system around 2/3 or 2/4...but if that one produces its a bonus.

We'll probably have at least a solid 10 day window between 2/5 and 2/15 and it could extend beyond that another week or so if we are lucky ad the MJO can robustly travel through phases 1 and 2.

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There is an interesting modeling affect here, where the operational runs are seemingly anti-climatic relative to their respective ensemble mean suggestion of what "could" happen.

The well advertised changing of the guard in the Pacific relay into North America, coming in the form of a +2SD western North American ridge with trough just NE of Hawaii held in the overnight teleconnector spread. In fact, the GEFs family is very tightly clustered on an overall PNA that rise to +1.5SD; considering that will have made for a total upward mode shift of over 2 standard deviation total, that is a strong argument for a mass-field alteration for the 40th parallel, on this side of the NH.  In fact, the CDC WPO/EPO together make a nod toward the AB phase of the north Pacific Oscillation, in general.  So it's a signal that's dug in pretty deep here.  If by transient we mean in and out in intra-weekly timescale, than we are not talking a mere transient signal.

If it adds any ... the AO last night initialized down to -3SD!!!! That is a total index mode shift of over 5SD downward, and provided established conveyors are equitably distributed (never a guarantee...), the whole tool kit is trying to build a stormy cold domain. The NAO is off in its own world in the GEFs mean, but with such an overshadowing implication from the bevy of other sources listed above, I am not sure that will necessarily be a detriment to the overall appeal.Putting all those ingredients in a blender and hitting frappe, we then pour a big glass of curvilinear meridional flow around a western ridge and then descending into - best ft - a Ohio Valley longitude quasi anchored L/W. With the antecedent AO heavily tanked, that kind of resulting N/NW flow through the Canadian Shield should transport cold air masses - the models certainly agree on that general result for middle and extended ranges.

What they don't agree on, across the board, from the CMC to the NOGAP ...Euro ...UKMET and back et al, is what details in the flow are going to ignite meaningful cyclogenesis events. Each operational guidance type I've seen argues for a different storm genesis really; not only that, they all more than seem to have their own native discontinuity issues, creating and dismantling systems in lieu of run to run impulse emergence and decay. It's really kind of mind-boggling trying to keep up with all those depictions over the last 2 to 3 days. Nested in all that noise, however, are two important systems I believe.  One is roughly D5-7, the other is 4 or 5 days later.    My opinion in this (if anyone cares) is that colder profiled systems during that time should be favored given to the fact that the AO curve is heavily south of 0.0 now, and during.   That's no guarantee of course... Just juggling probabilities based on available evidence.    

I realize for shear entertainment purposes it would be nice to see these runs latch onto a dreamboat run-way model and then guide her on into one's bed of aspired visions and hope...   We just don't have that kind of singular event for the time being.   I suspect there is room here for D3.5-4 lead for operational convergence - as the average lead time necessary for deterministic improvement.  While the overall canvas of the circulation from eastern Asia to Europe (W-E) appears well enough modeled, I don't think that smaller scaled events are sufficiently being sampled in the Pacific during these early pattern-transitory time frames.   Once the pattern is in, determinism may improve.  I'm looking back across the last several cycles of the operational GFS and ECMWF and both are erratic with what happens on the front phase of the first surge in the western N/A ridge, and all of those impulses in the flow are middle to NP origined dynamical packages - I don't see how that is being correctly handled with the immense complexity afoot.  

One thing that is certain, it would be a tremendous waste, no doubt, if we managed to verify the sort of tandem -AO/PNA rise/-EPO fall that multi-day advertised, if we also received nothing for it all - particularly when talking about it across the last week of January and into February of any given year.  Huge waste if that happened.</p>

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By the way, ...the editor here at American has gotten rather frustrating to work with... Flipping between preview post and back using their own buttons exposes HTML tags (so it appears) and so one must then navigate around them to continue their work. Additionally, text formatting options don't appear - not sure if that is a setting I may have inadvertently turned on ...or off rather. anyway..

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There is an interesting modeling affect here, where the operational runs are seemingly anti-climatic relative to their respective ensemble mean suggestion of what "could" happen.

The well advertised changing of the guard in the Pacific relay into North America, coming in the form of a +2SD western North American ridge with trough just NE of Hawaii held in the overnight teleconnector spread. In fact, the GEFs family is very tightly clustered on an overall PNA that rise to +1.5SD; considering that will have made for a total upward mode shift of over 2 standard deviation total, that is a strong argument for a mass-field alteration for the 40th parallel, on this side of the NH. In fact, the CDC WPO/EPO together make a nod toward the AB phase of the north Pacific Oscillation, in general. So it's a signal that's dug in pretty deep here. If by transient we mean in and out in intra-weekly timescale, than we are not talking a mere transient signal.

If it adds any ... the AO last night initialized down to -3SD!!!! That is a total index mode shift of over 5SD downward, and provided established conveyors are equitably distributed (never a guarantee...), the whole tool kit is trying to build a stormy cold domain. The NAO is off in its own world in the GEFs mean, but with such an overshadowing implication from the bevy of other sources listed above, I am not sure that will necessarily be a detriment to the overall appeal.Putting all those ingredients in a blender and hitting frappe, we then pour a big glass of curvilinear meridional flow around a western ridge and then descending into - best ft - a Ohio Valley longitude quasi anchored L/W. With the antecedent AO heavily tanked, that kind of resulting N/NW flow through the Canadian Shield should transport cold air masses - the models certainly agree on that general result for middle and extended ranges.

What they don't agree on, across the board, from the CMC to the NOGAP ...Euro ...UKMET and back et al, is what details in the flow are going to ignite meaningful cyclogenesis events. Each operational guidance type I've seen argues for a different storm genesis really; not only that, they all more than seem to have their own native discontinuity issues, creating and dismantling systems in lieu of run to run impulse emergence and decay. It's really kind of mind-boggling trying to keep up with all those depictions over the last 2 to 3 days. Nested in all that noise, however, are two important systems I believe. One is roughly D5-7, the other is 4 or 5 days later. My opinion in this (if anyone cares) is that colder profiled systems during that time should be favored given to the fact that the AO curve is heavily south of 0.0 now, and during. That's no guarantee of course... Just juggling probabilities based on available evidence.

I realize for shear entertainment purposes it would be nice to see these runs latch onto a dreamboat run-way model and then guide her on into one's bed of aspired visions and hope... We just don't have that kind of singular event for the time being. I suspect there is room here for D3.5-4 lead for operational convergence - as the average lead time necessary for deterministic improvement. While the overall canvas of the circulation from eastern Asia to Europe (W-E) appears well enough modeled, I don't think that smaller scaled events are sufficiently being sampled in the Pacific during these early pattern-transitory time frames. Once the pattern is in, determinism may improve. I'm looking back across the last several cycles of the operational GFS and ECMWF and both are erratic with what happens on the front phase of the first surge in the western N/A ridge, and all of those impulses in the flow are middle to NP origined dynamical packages - I don't see how that is being correctly handled with the immense complexity afoot.

One thing that is certain, it would be a tremendous waste, no doubt, if we managed to verify the sort of tandem -AO/PNA rise/-EPO fall that multi-day advertised, if we also received nothing for it all - particularly when talking about it across the last week of January and into February of any given year. Huge waste if that happened.</p>

Very nice analysis John. I almost bunned you but I know that as a writer, sometimes you can be sensywensy so I held off...lol. Seriously though, nice analysis, well written educational and informative.

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I gotta have a talk with mitchnick. This is not the winter to be up at 3am...lol.

I was half awake and then heard one of your buddies, that's right a squirrel, on the roof

sounded like it was in the attic

until I confirmed it was just on the roof, I was too far awake to fall back to sleep lol

sux being an old man at night!

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Very nice analysis John.  I almost bunned you but I know that as a writer, sometimes you can be sensywensy so I held off...lol.   Seriously though, nice analysis, well written educational and informative.

thanks Jer' - also, are we all collectively aware that there is a light snow - overrunning style... - in there for 72-84 hours? I haven't looked very closely at the thermal profile, but synoptically that should be interesting to my nerdly brethren

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thanks Jer' - also, are we all collectively aware that there is a light snow - overrunning style... - in there for 72-84 hours? I haven't looked very closely at the thermal profile, but synoptically that should be interesting to my nerdly brethren

Yeah we've mentioned it a couple of times. May whiten the ground for some.

Also, maybe some SHSN or even squalls tomorrow night possible. Rather unstable atmosphere tomorrow night. And nice breakdown BTW.

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Wow, the euro is all blocked up...lol.

That is ridiculous...it has a pretty solid east based -NAO too with big ridging into Iceland and Greenland...not really supported by the ensembles though...and the ridge building is just getting started in AK when you loop the end of the run on the hemispheric level...that would likely join up with the N ATL ridge later on...but OP runs beyond 6 days...

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Why don't the Europeans fix this bug?

The low really does cut off 2/3rds of the time and the progressive GFS is the one that's wrong.

EDIT: This time the 12z GFS agrees on a cutoff, it ejects it at 192 hrs though and the Euro keeps it there. Bugs after 192hrs will never be fixed.

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That is ridiculous...it has a pretty solid east based -NAO too with big ridging into Iceland and Greenland...not really supported by the ensembles though...and the ridge building is just getting started in AK when you loop the end of the run on the hemispheric level...that would likely join up with the N ATL ridge later on...but OP runs beyond 6 days...

Yeah honestly folks... I'd consider tossing this run altogether.   It has very little continuity with enough larger and smaller scaled features compared to it's previous (00Z and others for that matter) run to supply any confidence in its handling. If you look at the last 3 cycles you get 3 distinct impressions and that is wrong wrong wrong for any guidance type's determinism.   Horrible actually.   Not sure what is going on with the Euro this winter but this is not the first time I've been rather disenchanted by its handling of things.  Very different performance profile compared to last year and before.

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This first paragraph of NCEP's middle range forecast discussion today really nicely echoes what we have going on right now:

EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

148 PM EST SAT JAN 28 2012

VALID 12Z TUE JAN 31 2012 - 12Z SAT FEB 04 2012

MEDIUM RANGE GUIDANCE STILL SHOWS CONSIDERABLE SPREAD IN THE

EVOLUTION OF INDIVIDUAL BUNDLES OF SHRTWV ENERGY WITHIN AND AHEAD

OF AN EVOLVING MEAN TROF EXPECTED TO PUSH INTO THE ERN STATES BY

LATE NEXT WEEK... LEADING TO UNCERTAINTY IN THE TRACK/STRENGTH OF

ONE OR MORE SFC WAVES THAT MAY AFFECT PORTIONS OF THE ERN HALF OF

THE CONUS DURING THE PERIOD. FURTHER ISSUES ARE INDICATED WITH

ERN PAC ENERGY THAT MAY BEGIN TO INTRUDE UPON THE RIDGE BUILDING

OVER WRN NOAM BY MID-LATE WEEK... WITH THE SHAPE OF THE WRN RIDGE

IN TURN AFFECTING THE ORIENTATION OF THE ERN TROF AS OF FRI-SAT.

More over, I urge folks to toss the Euro run entirely - it clearly does not have an accurate handling. I suspect - purely supposition - that we are exposing a probable weakness, Achilles Heal, with the operational ECMWF where pattern differential of this nature causes it's "superior" data assimilation scheme (4-d system) to go awry. Interesting.

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Well, a ridge in the Western US on the ensembles in the long range doesn't necessarily mean the CPC charts are gonna show off the charts PNA forecasts.

If you look at the GEFS 500mb height anomalies on ewall from the 00z run, you'll see where the signal is. There's a big + anomaly signal with a ridge axis near Boise beginning at the end of next week and continuing until the end of the run.

So I wouldn't get too upset about the CPC plumes. Most of the guidance is still showing an anomalous feature in a good spot. Might not register as a +6 PNA but it'll do.

He is right that it likely won't get any better down there. :lol:

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