Typhoon Tip

Agreed … I’ve been impressed with ‘scalar’ analogue. fwtw It’s a revolving door thing as you hint tho. Depends on timing the noise within … which ultimately decided system typology

The only problem I see there is whether or not the ‘neutral’ height field departures in the SE are just an artifact of the flow compression - you know this … I’m just mentioning for the general reader. If so … those neutral layers in the TV are misrepresenting a destructive interference pattern. Insidiously, too, as it sort of hides under cloak of otherwise impressionable features -but the screaming velocities that result are not being represented. It’s not a show stopper … just an aspect to bear in mind. Anomalies don’t describe “why” they exist … it could be normal hgts because cold hgts are compressing S … but compression absorbs S/Ws.

Keep in mind … the COD is a weakened state …. It’s exertion in terms of forcing wave mechanical dispersion/modulation downstream drops below the forcing of the westerlies and becomes lower correlative. In other words … phase 8.1.2 migrations while within the COD do not represent in the pattern very well.

It’s good speculation but the reason the MJO has been reproducing that same behavior of collapsing into to the COD astride the 7/8 quadrants of the RMM has more to do with the wave attempting to move out of the marine continent … straight into a headlong -ENSO circulation footprint. And not being strong enough … it loses out within that destructive tension. Notice the wave seems to briefly amplify in 7s? Anology is a wave rearing up nearing the shore Phase 8 —> 1..2 is actually a constructive interference wrt the -AO should it succeed. It destabilizes the AA phase of the N PAC Basin … triggering tendencies for wave migration into higher latitudes which proceeds blocking events.

Interestingly… The ensuing 0Z operational Gfs was - imo – largely improved over priors in terms of actually representing some of the forcing we’ve been collectively observing in the ensembles for the past week. Pretty much one of the first ones I’ve seen actually do that… I’d also watch 7.8.9.in addition to 13.14.15 Those two intervals have been there pretty much all the while in spite of all the modeled din and fractal efforts to hide them it in the noise. It’s understandable for the midmonth. Christ, talking about at the 300+ range I think the 8th has a chance to be a flat, minoring event with option for more should a GGEM -like solution pass under our latitude. Low levels in either GGEM or Euro option look cold due to low level thickness wedging off erstwhile -EPO passing over recent improvements in cryosphere in Canada The Canadian has a deep vortex coming overhead and deepening further at 500 mbar, pinning under the -NAO … which this latter aspect is shown some remarkable residence/continuity for a long while as we all know by now. The 8th period of time is over 7 days away so there’s time for that to modulate into a little bit more of a concern. Not a leap to tell winter enthusiast an opportunity to monitor. It’s really the inflection in the index modal change in the NAO. Which has admittedly a lower but still above N/S correlation with activity over the eastern mid latitudes of the continent for a reason. 0ZGFS has the 8th system passage but it seems to be responding to NAO forcing later than the other two guidance types and that -assuming causality - allows it to sneak west through the Detroit transit The folks that are seeking big dogs it’s more likely the event between the 13th and 15th evolves that way imo from what I’ve been seeing lately. Bearing in mind … in this context that is like I don’t know the difference between 10% above climo vs 20% above climo… because it’s just too far out in time. Definitely fits the larger hemispheric timing and cadence tho. Interesting.

I mentioned that two days ago and I mentioned something similar today the EPO was being kind of stingy in this thing… Seems to be abandoning the guidance - last week there was more of that with resulting -30 C 850 plume down to southern Manitoba … so yeah that’s a change in the last three days. That also changes the landscape of this thing. I mean NAO blocks are less useful if they don’t have cold air directed underneath. Once again the models charming us with day 12 delusional grandeur … lol j/k …sort of

0Z NAM in just 12 hrs takes the hydrostatic hgts from 553 to 519! Thats helluva a front

It’s interesting how these ens means keep upping the ante but the operational versions meander.

Ugly Euro run. Lots going wrong around the -NAO … it’s kind of interesting, the one metric that more typically demos poor predictability is the one observable aspect that’s showing any continuity.

… It’s an evolving situation… I consider that Lakes cutter around the 7th as a boundary storm along the mode change / mainly -EPO driven … a transit that last week looked like a positive +PNAP triggered passage. But the PNAP aspect’s been delayed possibly indefinitely I’m not sure… I mean whether we get a western North American Ridge and all that jazz thereafter is still under debate to me but yeah it’s been showing up in some of the guidance. It’s nice to finally see the operational guidance versions of the Euro and the American coming around to picking up the exertion of the negative NAO. Man it’s unnerving tho … The NAO history is a catalogue of disappointments … when it looked clad, but then never really developed and/or ended up doing some variation that didn’t parlay well. And so here we are trying to depend on one that’s still modeled beyond day 7 …particularly towards mid month that’ll stroke winter enthusiasts some 4 weeks ahead of climo no less. There is a little solace in the fact that when you step back and look at it from orbit the hemisphere appears that it has no choice but to end up in a negative NAO. I’m just hoping that model magnification will actually be our ally in this case and that what verifies is a more moderate negative NAO blocking …such that doesn’t become overbearing

Nice cold cap out there this morning. Dropped to 22 then the clouds came over right at dawn and now it’s mid morning with heavy frost everywhere…

mm ...I think the 13/14th is lit up some in the ensembles ( about a 1/3 of them) for a reason, too. Not sure about the 17th -20th, but the period between the 10th and Christmas in general appears vulnerable for activity. Suppressed ambient polar boundary pressed into heights lingering modestly positive in the deep south, yeah... an index modal change drawing the mid levels back N over that boundary in the means is quintessential H.A. There was that in the 7th...9th but it seems to be correcting further out in time. We've been discussing elsewhere ... but moving an along an event spectrum from cutter --> overrunning --> more formulaic coastal spanning 10 days to two weeks mid month, isn't a bad idea. Even if one of those verifies..

I'm not a geologist - though have side-carred a lot of interest my whole life ... I'm under the impression that the subaqueous nature of the eruption is at least partial in why the S02 was low? - compared to eruptions having less energy, such as Pinatubo ... with less VEI but was richer in S02. (these are not statements; these are rhetorical questions)

You haven't mentioned anything terribly distracting ... I mean, whether you are right or wrong regarding NAO blocks merging with winter killing STRs is really 'sides the main value of the point: NAOs are inherently poorly performed and stochastic index fields.... Modeled blocks and/or decaying thereof, are often proven to be red herrings. That's the take away. 'don't count NAO chickens before they hatch" As far as getting this block to initially verify ... I think it's above medium confidence, personally... I'm seeing the scaffolding at planetary scales that are directive in this case. If I had to put money on it, I'd say we'd see a system materialize for the 13th of the month... but I wouldn't be surprised if a flat mix headache happened a bit sooner. Before then, we are social media booked with therapy appointments LOL

yeah there's interesting weather prior to the balance of what interests people in here today. That could be a potent squall and wind event, west to east, through the region Wed evening. Southerlies gust to 45 or even 55mph, with a sharp wind shift and burst to 60 and blinding swept rain for 3-5 mins with that ribbon echo. Interesting turn around in temperatures ...with an 18 hour cool snap that goes quite a bit in the other direction by Saturday... Then we'll see how things modulate next week. The idea of the blocking is likely to pan out... but the variations in how it effects the flow and what particulars that will entail still has plenty of room to move around in guidance after Saturday

For what it’s worth… Probably nothing for this group but Saturday may just be very nice out of doors if it doesn’t get too windy. By Sunday we have a really impressive negative EPO structure with a very intense cold plume channeling down the eastern front range of the Canadian Rockies towards Manitoba in this operational Euro run. Insane gradient from the border states to Florida

There’s also a subtle tendency to delay the onset of -EPO … which others seem to interpret as a zonal regression? It’s still a curvilinear flow around the Alaskan sector given more time, however. As far as the -EPO … it’s really kind of required to set the -NAO into retrograde d(amp) through complex/transitive wave transmission … I mean you can see the sequencing of the hemisphere spanning 10 or so days. First the EPO —> some sort of Dec 7..8 trough ejection through the east —> big chunk of warm hgts/advection surge up the western wall of the semi permanent W Atlantic ridge, which migrates into the lower D Straight where it marries in and triggers repositions the the -NAO from the eastern toward the western limb of the domain.. It all started back in the C-NE Pacific in the mid range. It’s fascinating really. How the PAC transmits a wave signal around the globe like that. …anyway with all those moving pieces going on over the next 7 to 10 days I mean it’s utterly in germane to even consider what a singular model guidance is illustrating on day 8 through 15+ but I get it… people are bored. Plus there’s a little bit of addiction to excitement going on when it comes to the stuff that’s another discussion lol. All this stuff looks really intriguing but it doesn’t mean jack if we gotta wait 10 days …looking out the window and it looks like it does right now which is completely uninspired. So all that people have to talk about is really their addiction withdrawals lol

Yes it establishes a better footprint there, but I think it’s also hinting at some of the compression/limitation associated with too much velocity that we were talking about earlier…

Not sure I see what you guys are talking about reading the GEPS … Looks like two cutters and a big Ohio high pressure as the major identifiable features through the end of Oh cause I’m looking at the 00z version.

But gives everyone nothing in the dailies lol

Unrelated to meteorology per se but it seems that area of the world has a history of these kind of single pop detonation out of the blue… I.e. Krakatoa and the like. Tambora too. I’m not sure that Krakatoa or Tambora gave very many warning signs before hand? I’m not sure that. But this thing just showed up.

Yeah that’s true over the long haul… However we have to consider each case within its own merit. I mean it’s kind of the same logic of climate doesn’t predict the weather; the weather creates the climate. It just means that something more apt to happen in the middle of the winter can certainly happen at the bookends - even if it’s a little less likely to have that take place. Blah blah. But you know I don’t actually dislike the idea of more light to middling events like you mentioned because I’ve been toying with that myself frankly. Maybe even a flat icer. If the ridge retrogrades west like Will and others are mentioning… Clippers are an option too. I agree that if one is searching for bigger players … a relaxation is preferred. Maybe we can even get into a +0 to -2 weekly oscillation with the NAO … Get a +PNAP return state then we’re really carving fillet mignon

Mmm … in fairness? that is not AS true for the NAO.

This will probably spark some debate… Or be ignored – not sure. But you can see how the NAO is actually the more nonlinear wave response from the Pacific as its source for construction just by observing how the polar jet across the North Pacific is behaving in tandem. it’s a meaningful observation because it harkens to the idea that this may not just be a random block that comes and passes over a three day period. It is more systemically rooted. Don’t have a problem with the occurrence I have a problem with the other aspects I mentioned above in that other post

It is but in all honesty … yeah, I find myself a little concerned. What underpins the expectation relates to ‘too much of a good thing’ I’m not likely to take the any operational GFS solution verbatim … its overnight renditions of the NAO block were comically extreme. I mused internally, ‘it’s like it’s gathered up all the last 25 years worth of CC and stored it over the Davis Straight’ But it does harken to the overkill compression problem that can overwhelm from Texas to Bermuda with meat grinder velocities The ensemble means of the GEFS and EPS are less epic block SDs … but even they hint at velocity anomalies within eastern conus region/trough I’m less concerned about NAO blocking merging with west Atlantic perennial heights …—> cutter pattern. But like Feb 2007 if the ridge is berserker and backs SW, the polar jet forced through the TV region basal flow rate is over a 100kts. S/Ws get absorbed as opposed to generating goodies The other aspect is… we are all hungry to get winter going as fans of the season and model cinema addicts (LOL). But seriously, there’s been no mentioning how NAO prognostics are still the biggest backstabber index forecast problem that exists to deterministic techniques in this field. I’ve been thinking about this but haven’t brought it up because the arctic oscillation, which is a little bit more dependable, has been exceptionally negative in the outlook from all guidance sources and techniques for quite some time and they obviously share domain space as does the North Pacific etc. etc. That tends to foot the NAO.