Typhoon Tip

I suspect so... You know, something I've noticed in the past, not 'reliable' per se but, as the noise of the mid range washes out ... sometimes the extended reveals a 'canvas' so to speak. It could be early detection making that layout and as the time nears and the physics get more detectable (objectively..) - that's why the EPO "bursts" ...WPO and NAO for that matter

Agreed, bold. Not sure about the other aspects you're describing - I've kept my observations more orbital. But the former aspects, I covered that in post yesterday. Interesting statements from the MJO desk lend credence to +PNA. At long last ... finally an MJO wave that is actually forecast to move into a constructive interference wave spacing by mid month . I would not be surprised if that was led by a -EPO burst; the projections on that are so far so-so and vague for now

Oh pretty please, with sugar on top?

That's really been all I've concerned over up to this point, getting the pattern orientation into the best fit with the numerical telecon. At some point along the way, that 'fit' should host a more coherent system result, yeah.

People sometimes don't consider the sub-geostrophic wind is different than the isobaric layout enough. It is pointed more across the isobars. If the isobars are oriented west to E, surface drag and restoring requirements (physically) forces the wind to go across the isobars in the lower levels. There are then two factors that will augment that even further: 1 cross-isobaric flow that sets up during rapid cyclogenesis scenarios. It happens when pressure falls in the core faster then the time dependency in the Coriolis force; the immediate restoring flow responds quicker and the air goes straight at the low - barring terrain. 2 ageostrophic flow happens when there is a cold air present N, assisted further if there +PP situated N. That can cause the wind to also exaggerate the sub geostrophic flow.

heh... I just saw that Euro run. That 4th event's colder in the interior push comes to shove with that high placement. The +PP is built in prior to the system arrival, not as or racing. Typical to be too mild in the lower 1300' of the atmosphere from this range when/given that sort of set up. But as we've been collectively intimating ... it may be moot anyway as it's not abundantly clear which wave in that troika ends up dominant. Possibilities range from one in lieu of the others, to all three interfering and nothing gets done... Agreed ... the period is of interest/still -

Remember Dec 1996 with the twins -

GFS trended better at 500 mb but decided to back off some of the Quebec +PP ...so the net result is a slightly warmer solution - still marginal ... and not a grouser solution considering the time range. CMC went more sfc PP up N. Slightly cooler at the surface with more secondary but it's still just +1C on the wrong side of marginal. Again...nothing tormenting from this range. The GEFs as I have seen them are only out 156 hours as of this typing ... interestingly more impressive with western hgts aft of the trough ejection - that's likely to ( or should) cause more amp conserved coming east/ more coherent signal near the ~ D. Marv to BM

Interesting article ... I suspect many in this social media engagement have ruminated this, too - https://getpocket.com/explore/item/the-strange-blissfulness-of-storms?utm_source=pocket-newtab-en-us

Yeah, I was noticing some contention in wave spacing/focus too. Differences in that regard between the Euro (operationals) and the GFS shows what it can mean at the surface. Ex, the Euro puts subtly more emphasis on the lead wave and widens the gap ( which is unusual actually for this guidance to 'stretch' the field, at this range but it was what it was ). But, by doing so, it benefits from an acute fresh baroclinic gradient and pummels the interior with an early seasonal anomaly. Contrasting, the 00z GFS puts less emphasis on that lead wave, while maintaining enough integrity there that it does evac the b-c and well...that's technically neggie wave interference there. The arriving and closing deep mid/U/A trough looks awesome at 500 mb but you go look at the surface evolution and its sort middling and malnourished. All the above needs to be ironed out. Like I said just recently ...I think we are on the edge if we can just get the GEPs to come around some ... we'll have all three trending rightly for something to go down.

heh i might take any "c" at this point

I'd like the GEPs to come around some. I think we're close to starting a "period of interest"/signal thread for the 4th -6th period of time ( Will and I spent some time going over the vitals yesterday, the aspects of which are still carrying on ...). With that source added along with some continuity from the others, ...we've started successful threads based on less before. Quickly, a few more members of the EPS and GEFs respectively have come around/added to the lowering pressure from the D. Marv to CC cyclone transit, which given the antecedent mass field behaviors with a ensemble weighted trough ejection from the west, plus the numerical telecons actually indicating a +PNA --> +PNAP expression etc (... to mention the less advertised -EPO load) that region statistically starts glowing.

Very interesting statements from the MJO desk at NCEP re the present and future ... - to me, the aspects portend a very amplified pattern potential over the Americas during the 2nd half of Dec. I suspect the Euro may collapse the phase 4 idea some .. perhaps not all. I rather like the GEFs notion of the wave's slower decay in the attempt/RMM before reemerging where the wave will (by then) be in constructive interference with the ENSO, 7+. I'm just not sure the polar westerlies will fall into sync, but ...with the recent very deep diving -AO quite plausibly lingering out there in time, that "might" set the table for a constructive interference where the MJO is more successfully modulating the L/W distribution. So a little speculative, ...but is based upon extrapolation into known correlations so we're not just writing science fiction here.

The other way around is better. We used to have a saying up at UMass Lowell, 'First it gets warm, then it gets cold: BOOM' It seemed to also bear out statistically. But, the principle is the same in either direction, yes... In either case, large scale regime changes of temperature requires large mass fields ( indexes) in a state of change. Storms happen during those times of change as a matter of course. Going from cold to warm is less proficient because front side cold supply can be escaping with the gradient some half the times the storm is approaching. We end up with cold going right to marginal rain ... Contrasting, cold arrival tends to outpace the Pacific and/or diving S/W supply upstream. Along they ride running up underneath the newly (fresh) cold supply and ...well, fun ensues. You'll get a kink on a miller A boundary, and/or a strong clipper/miller b type disturbance tunneling though the cold troposphere. Personally? I prefer the latter to the miller A. I have seen some nasty pig miller As with their big PWAT transport. They are fun where it's all snow, but therein is the problem. The bombogens 'tend' to be Del Marva to just off the Cape. And captures are all but exclusively miller Bs. They take place where deep cold (relative to season) situates in uneasy proximity to a warm source - that is quite natural during recent cold arrival, from ~ E PA to Maine. Just waiting to get sucked S underneath an an intensifying E flow between 850 and 700 mb. All of which is more likely during and aft of the warm --> cold transition variant. There can be exceptions of course... There's the theoretical states where a miller A gets captured by a diving impulse aloft ...I suspect 1888 and 1978 might have been that rarity. Kind of a "miller C" if you will

You didn't ask me but ... I suspect the Euro is less correct about 4-6 phase space. It's not even clear the tropics are completely integrating a forcing above ~35 N to begin with. The dispersion mechanics don't seem to be overcoming mid and upper latitude flow and anomalies thereof It's sort of counter intuitive, but if it were ... the 4-6 wouldn't be correlated well with warm ENSO and would tend to be in destructive interference. So why would an MJO of any kind be able to? In other words, inability to escape and modulate would work in both directions. I've noticed a lot of MJO reliance creeping back into the various sub-forum chatter when again again again... the MJO's are constructive or destructive interferences - they don't really drive the patterns, they either reenforce or offset by less than totality - there are times when it's completely unable to at that.

What's +3 in Anchorage in November .... 19 instead of 16 LOL J/K

It's kind of a sloppy usage, yup. I noticed that myself - they come and go.. But, I've come to realize that in order to affectingly communicate, you have to go with what people understand? The "group understanding" is more heavily influenced by the spirit/mood of the era, than it is by longer term/'more correct' this that or the other thing.

fwiw -

That GGEM is right on the fence from cashing in on this idea..It's like all or nothing with that polar high up there. There's a weak analog to a '50/50 low' there, with polar high/confluence over top orienting between it, vs this important +PNAP pulse. If that presses just 'this much' more, it's going from cold rain to blue snow and whole different world evolves. It's almost harder to keep that mix. Either or Thing 4th-6th period has been repeating since last Monday - I glanced at that charts over the course of the holiday week while down in Va Beach ... when it was like hour 312 I'll just convey ... the reason for 'chance to go colder' is/are some canonical telecon behaviors/projections that 'tend' ( not always, Kevin) to send cold air across southern Canada - often times we correct toward subtle but crucially more confluence to also aid in delivery.

Hint hint, I wouldn't mention it if there weren't a chance ( in my head ) that it might trend colder lol. But yeah, we'll see - 'period of interest' is like a step below 'signal'

There is a 'signal' (more apt a period of interest..) I've been watching for Dec 4-6th.

Per my own observation, there are homages to favorability, both in observed recency, and in the pattern created by guidance, going on thru mid December - perhaps the 2-3" last week and this deal late last eve up N hearken to being 'favored' as such. There are also discrete telecon modulations that blah blah might be related. The problem ( the way I see it) is the fast nature that is physically present. It's excessive progressivity becomes a destructive interference. It's tending to "hide" potential because wave spacing is being stretched so far that new albeit transient inflections in the flow materialize due to Coriolis forcing. Speed is competing with an El Nino.. It's sort of a split hemisphere with any correlative nature to ENSO being sheared off around 40 N. I would even consider the lack of emerging STJ is really because of that virtual boundary is sort of 'trigger stop'

Nice blue tinted cryo dawn photos above. Been glancing at guidance here and there while out of town just to keep a toe hold on trends. Homages are there for cold availability ... only when there are no disturbances. This was similar to Dec 2014 and pretty much all of the 1980s ( lol ). I'm not suggesting this will go on to being the theme of this particular relay into winter, but over the last week to 10 day's of guidance we've been BN then normal to modestly above with rain showers around a 2 to 3 day cycle. Despite that, T-Giving eve (last Tuesday?) 2-3" and now this overnight up north were sneaky. There is a signal that I've been watching for Dec 4-6th.

I also suspect we may deal with this whenever the -EPO pulses during ensuing months - the residual HC height dispersion from the south is just going to offer lingering resistance every time we tried to load colder heights S of the 50 N and we'll be sending B.C. wave to NS in 72 hours flat ... Perhaps not every time but a repeating theme.

I've been trying to explain to folks ( it likely comes off a little heavy handed but don't mean it to be - ) that there's a fair amount of amplitude signaled in the numerical telecon spread and behavior. There's a sequence of events in the spatial/synoptic coverage that fit the canonical relay between the -EPO --> relaxation --> into a +d(PNA). I suggest it's throwing some operational model versions into a tizzy. The former signals an intrinsic pattern change from the E-NE Pac arc downstream over the continent and well ... when have pattern changes ever been exceptionally well handled. I would take a step back from really taking any particular operational run very seriously in lieu of ensemble mean. I looked at the EPS and GEFs from 12z and saw reasonable continuity over prior runs. It's really the operational GGEM and GFS that are acting like the unmanned fire hose - but again ... I sort of give them a break at D6 when trying to assess through the inflection of a -EPO / rising PNA relay. My feeling is that a middling system that is moving fast reenters the GFS frames. I also want to caboose Will's sentiments about fast Novembers - that is particularly true when the NE Pac is trying to load Canada ...and once over true again anyway as an observed hemisphere during cold seasons, with increased frequency state over the last 10 to 15 years ( regardless of any longer term planetary indices, too). It's relevant to discourse because these systems are torpedoing