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Late autumn, early winter model mayhem

Typhoon Tip

By Typhoon Tip,
in New England

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Typhoon Tip

Typhoon Tip

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Briefly ... 'front loaded winter' probably has no technical definition and is subjective in our wacky world of weather-related social media.  Anytime there is snow prior to this day's particular holiday, most sane connoisseurs of the interpretation game would concur, that is an early expression of winter - but to truly be "loaded" ? That means just that.  In other words, it has to have staying-power.

Which...so far, we obviously have had neither.

So, enters the arguments of being prior to Thanks Giving as "unrealistic expectations"   - sure...  In fact, I only remember one winter in my life that truly qualifies, and perhaps five or so that borderline did, so... per my many thousands of years of existence, that inclines me to agree.  But, I don't care about expectations? It's not about that.  It's about "weather" it happens or not, and... so, the exceptional front-end loaded has officially failed and we move on to the next. 

...Which is the standard front end-loading plausibility (and hope...).  So what is that ... for me, the means getting cold enough to retain a snow cover, with more than one storm scenario between approximately the first of December and Christmas. Again, leaving climo and that expectation/head-game out of it (and, somewhere along the way, it is hoped we'll have intelligent, lucid discourses about the modeling biases and depictions). 

Right now, they don't look good for early winter enthusiasm - granted. In fact, the CDC version of the GEFs teleconnectors are horrible .. They are putting up +2 SD WPO numbers ... Meanwhile, the American-based modeling for the MJO has gotten recently more coherent in the right-side phases of the Wheeler diagram ... It's hard to know the chicken and the egg there; is the MJO forcing the WPO domain space, or...is the WPO in a constructive wave interference, thus, ...the models lower stress in those parts of the wave-space diagram.  Either way, those two concurrent signals are ... hostile to the Pacific (meaning not good for North America).  -PNAP is probably preferred out in time..  The CPC version of the AO/NAO/PNA are not quite as dire looking, but ... we are still in the transition season, and all the above tends to suffer both verification and correlative results at this time of the year for a whole host of other reasons. 

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ORH_wxman

ORH_wxman

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EPO looks pretty good in LR. WPO is def positive because it's almost a hybrid Niño look in N PAC...lower heights near Aleutians and WPO and higher heights at EPO/PNA area. Though we still see somewhat of a SE ridge and some troughing in the west via split flow...so that's what I mean by hybrid. Def still some Niña look too. 

NAO looks to go negative again too at the end of the 11-15 day...we will have to wait and see on that but if it materializes, that would be very good in tandem with the PAC. 

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Typhoon Tip

Typhoon Tip

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4 hours ago, ORH_wxman said:

EPO looks pretty good in LR. WPO is def positive because it's almost a hybrid Niño look in N PAC...lower heights near Aleutians and WPO and higher heights at EPO/PNA area. Though we still see somewhat of a SE ridge and some troughing in the west via split flow...so that's what I mean by hybrid. Def still some Niña look too. 

NAO looks to go negative again too at the end of the 11-15 day...we will have to wait and see on that but if it materializes, that would be very good in tandem with the PAC. 

It's been a long while since we've sown the seeds of an ice storm pattern...

and by that ... I don't mean 2008, which was a freak occurrence really.   i mean one of those continental deals where we pearl out a shallow polar air mass wedged in from the N, and an active boundary propagates waves of zr and sleet.   they last for a couple days of cold smell mixed with wood smoke, and the sounds of mortar fire and shimmering glass from timber falls of ice. 

in fact, it's been over 10 years really...  1998 was epicosity in that regard, but may in fact be the last time that sort of duration ice set up.   2008 was a very localized over-achiever based upon perfectly situated draining low DP air right under an elevated terminating PWAT transport...  it was almost a dice roll for sw NH and to Worcester.

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ORH_wxman

ORH_wxman

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22 hours ago, Typhoon Tip said:

It's been a long while since we've sown the seeds of an ice storm pattern...

and by that ... I don't mean 2008, which was a freak occurrence really.   i mean one of those continental deals where we pearl out a shallow polar air mass wedged in from the N, and an active boundary propagates waves of zr and sleet.   they last for a couple days of cold smell mixed with wood smoke, and the sounds of mortar fire and shimmering glass from timber falls of ice. 

in fact, it's been over 10 years really...  1998 was epicosity in that regard, but may in fact be the last time that sort of duration ice set up.   2008 was a very localized over-achiever based upon perfectly situated draining low DP air right under an elevated terminating PWAT transport...  it was almost a dice roll for sw NH and to Worcester.

We seemingly had a lot of those setups in the 1990s. I even remember a really good one in 1989 as well during that awful '88-89 winter. 

You figure it'll happen again soon enough. That western trough with frigid air in Canada bleeding over the top and then energy ejecting out of the western trough in ripples is always a classic look. 

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Typhoon Tip

Typhoon Tip

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right ... that's the key, that return flow confluence structure,... almost like a back-ground La Nina with a +PNA 'attempting' to pulse through ends up being that way.

For now ... man, nondescript pattern from misery hell unrelents - good christ.  I mean it is insidiously wending its way into verifying the absolute worst pattern (for me anyway). I mean, if it were record warmth... but things just can't (or won't) be interesting at least excuse imagined here -

maybe that is an achievement in its self.  Banally destroy the earth - haha.

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Typhoon Tip

Typhoon Tip

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Over the next two weeks, I'm still not seeing a very strong teleconnector signal pointing to cold and snow through day 10.  There may be some signal toward the end of that range.

The skinny version for the next two weeks:

The Pacific circulation at middle latitudes doesn't appear favorable for sending/forcing those pattern types over North America

The NAO is attempting to sink in both the teleconnectors and more dependable operational models; however, the inherent stochastic nature of that headache domain space does not lend to confidence.

The longer version...

Interestingly ... a negative NAO is reflected off and on among the traditionally more dependable, operational guidance types, as there is a semblance there for a more favorable pattern heading toward day 10 (ish), associated with eastern Canada/NW Atlantic.  Not consistent though... Just look at the difference in the la-la range of the GFS' 00z to 06z ... You could argue "la-la" range, but it's certainly symbolic of that index handling.

And so, I caution, you may recall the NAO betrayed us pretty patently over the last three weeks of total model/teleconnector progs --> verification.  It was supposed to tank to some minus two or even three standard deviations; but perhaps more importantly, many guidance along that legacy constructed very healthy, flow instructive ridge nodes invo the D. Straight region. What verified of all that was very pallid by comparison and really ... if any negative NAO transpired at all, it was too idiosyncratic in nature to even have effected the weather locally. That's what we got out of that shimmering and giddy looking complexion the models and teleconnector were more than merely suggesting.

If nothing else, that is a text-book shi!t eating lesson in why the NAO is both highly variable/hard for models to handle, as well as over rated ... That thing seems to need a very narrow bandwidth of allowable spacing, both temporal and geographically, in order for it to pay winter-lust dividends where we are.  As an aside: there is a reason why Heather A. statistical science from the late 1990s concluded that the "regime change" precipitation enhancing was more coherent in the PNA when comparing those two index modalities.  ... All index domain spaces

Anyway, point being, I would definitely take any teleconnector progs and/or operational modeling with a healthy degree of incredulity wrt to any NAO handling. ...Which is not to say that a block like 00z GFS won't happen. Just to point out that its dicey at best. 

That all said, that's where it really ends pending last night's numbers; which I have not seen, admittedly, but through yesterday, the WPO and EPO domain spaces are not very stable. I would almost be happier for winter aspirations if the WPO were negative and the EPO were the one that was positive,... but here, we have a very stoutly persistent and strong +WPO number set unrelenting as of late, and the EPO is acting like an errant fire hose spraying nightly values on either side of 0 SD ... It's almost like the eastern Pacific circulation medium wants to be more favorable, but the west end is holding it back... or something. Anyway, the MJO fits nicely into a +WPO framework too, with a reasonably robust last Phase 3 thru early Phase 6 migration. That is a positive/constructive interference which doesn't lend very well to prerequisite -EPO for North America. 
 

 

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ORH_wxman

ORH_wxman

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Mentioned by several folks in other thread...but that is pretty awesome stuff in the 11-15 on all ensemble guidance. 

The good news is that it is in fact getting closer on the ensemble guidance and it gets more intense further out as the ensembles can see a little further into the pattern each run. It's a strong signal for this far out which lends some confidence.  

 

 

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leo2000

leo2000

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27 minutes ago, ORH_wxman said:

Mentioned by several folks in other thread...but that is pretty awesome stuff in the 11-15 on all ensemble guidance. 

The good news is that it is in fact getting closer on the ensemble guidance and it gets more intense further out as the ensembles can see a little further into the pattern each run. It's a strong signal for this far out which lends some confidence.  

 

 

What about that volcano Agung looks to be having a second eruption have any effect on us?. 

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WxBlue

WxBlue

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And this is why you shouldn't freak out over few weeks lull from "cold" weather.

Honestly, the timing of the upcoming pattern is excellent. Much better to have that look Dec 7 to 17 than Nov 20 to 30 with the climatology due to get colder. Hopefully our patience is about to be rewarded.

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Typhoon Tip

Typhoon Tip

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While I am not sure what sources Scott is referring/inferring, the CPC ...which calculates its index using the mid-level geopotential heights off the GEFs, was substantially improved beyond about Dec 2nd (ish).

Climate Prediction Center:

As of this morning... that source has a nice tight clustering of members heading into day 10 ...better so than I have seen to-date since November 15 or so... That clustering/agreement is for the PNA to surge to +1 or +1.5 SD

The NAO has also gained more coherency for a negative phase state, with all but two cluster-errant members showing a distinct ...and "perhaps" tantalizingly telling "longer duration" run toward a nadir that doesn't really even get achieved ending week two - I don't know if there's any truth to the following sentiments, but considering the longer term intrinsic variability and weak skill in predicting that particular domain space, having more rather than less time in negative(positive) lends to confidence that gee ... maybe these technologies will actually succeed in verifying one of these stints. (christ ... sorry that last -NAO fiasco was annoying)

The short version of that is the operational models could very well need some correcting more amplified if indeed the GEFs -derived PNA gets to +1.5 SD, with even a modestly negative EPO concurrently taking place.  (EPO and PNA have a relatively robust positive correlation, so +PNA with -EPO is actually less stable, but therefore means ... very steep flow potential).

I invent phrases in this bag of head-games for the sole intent of Emotional Codependent Operational Meteorology (ECOM)

... I'd like to propose a new terminology to be added (perhaps) into the local social media/model lexicon known as "ECOMism" ..the art of modulating one's purely subjective impression of what to take away versus throw away from the various predictive tools (only the one's that look good to begin with, of course) that satisfies what they want..   No?  ... anyway..

One such phrase that sounds off in the internal monologue is called "correction vector" ... It's really probably got more veracity behind it than the tongue-in-cheekism above. It's based on balancing teleconnector trends, against the trends in the operational guidance.  Somewhere between 50% and 100% of the time, reality will precipitate (pun intended!) out of a blend of those two.  Logic then dictates, if one or the other is signaling a conceptual overview that ... for lack of better word, belies the bigger consensus, the 'correction vector' should point toward the truth. Simple premise but ... usually these things turn out to be vastly simpler than the journey it takes to get there..

 

 

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