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The Mystical Month of February--Long Range Discussion

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10 minutes ago, C.A.P.E. said:

Yeah I saw that, and no I don't buy the big blocky look at this point. Once again that ship has sailed, and it was a ghost ship yet again I'm afraid.

Yea, surprised that the CFS goes off on a tangent so early in the run.  By week 2 it is already incredibly divergent.  But unfortunately the way it evolves the pattern is highly dependent on the NAO block.  Without that I can see how that becomes the trainwreck the EPS is in week 2 and then week 3-4 are in doubt as well.  

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2 minutes ago, psuhoffman said:

Yea, surprised that the CFS goes off on a tangent so early in the run.  By week 2 it is already incredibly divergent.  But unfortunately the way it evolves the pattern is highly dependent on the NAO block.  Without that I can see how that becomes the trainwreck the EPS is in week 2 and then week 3-4 are in doubt as well.  

Just for curiosity,   I wonder if the way the CFS gets the block  going is from a rather deep North Atlantic Ocean storm , sort of a wave breaking event and a NAO response then it goes form there.  

 

 

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14 minutes ago, frd said:

The NAO issue might have something to do with the QBO and how it is moving since late November .

I also mentioned in that other post I did where the met stated the QBO might have halted the proper reponse from the SSWE to downwell in a typical manner. 

and he mentioned again, ( backtracking ) the unusual nature of the SSWE , how it was driven ( wave 2 versus wave 1 ) and the way the main vortex split into 3 may have as he stated diluted the response .  All very interestiing  

maybe just maybe a short bit more sudden wind reversal and then a recovery would have been better in my mind, but I am really reaching.

also think base state leading into to this winter,  December was horrible in terms of the SOI , so again what did that effect have.   

 

 

I know I have said this before, but my optimism for a legit -NAO developing the second half of winter was based on a correlation to a CP weak-moderate El Nino. Without atmospheric Nino-ish behavior, I doubt we see anything other than weak/transient NA ridging at this point.

eta- QBO is a factor but was moving in the wrong direction as winter approached. The SSWE probably had impacts as well but that is way beyond my level of understanding. Ultimately, what drives the NAO (the negative phase in particular) is not well understood. It figures one of the most important indices for snow chances here is also one of the most esoteric.

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32 minutes ago, psuhoffman said:

Agree on the retrospective, but with the soi mostly neutral to positive and the mjo cycling around 4-7 all winter the non nino features infecting the pattern made sense. I’m more confused to see a -soi mjo phase 8 and still not get the typical pattern response. 

See and the fact that nobody seems to be able to figure out what the heck has been going on this winter really bothers me. How is it after all these decades of data...that this winter is somehow different from the rest in terms of it utterly baffling even the best met minds? Somebody gotta figure out something! That's what has made this winter mentally taxing at times--nothing seems to be working the way it should (resulting in both good and bad outcomes). It's not just our usual "missing a threat" like a bad track or something...but just the entire bigger picture. All winter it's been "well this usually does this, by why it didn't we don't know". I do hope after this season mets will take a long hard look so that maybe we don't have to go through this as much. End rant...

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2 minutes ago, Maestrobjwa said:

See and the fact that nobody seems to be able to figure out what the heck has been going on this winter really bothers me. How is it after all these decades of data...that this winter is somehow different from the rest in terms of it utterly baffling even the best met minds? Somebody gotta figure out something...that's what has made this winter mentally taxing at times--nothing seems to be working the way it should (resulting in both good and bad outcomes). It's not just our usual "missing a threat" like a bad track or something...but just the entire bigger picture. I do hope after this season mets will take a long hard look so that maybe we don't have to go through this as much. End rant...

like Bob says, somethings the weather just weathers...

obviously there is a causation but we do not understand every detail to to every finite level...and it is possible the causation is linked to various very small sensitive effects and not just one or two major ones making it much harder to identify why thing's aren't going according to expectations. 

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Seems when you look at the QBO for this winter we have a rare occurence. First time I heard of this combination taking place. @Isotherm was talking about things this morning.

He states there are several things at play in regards to why we have not seen the typical responses including the blocking.

I  brought over this section from his detailed update over , since we had touched on the QBO earlier. 

His entire post covers a lot more, and is over at 33andrain.   

 

He states :  

<<<

 

 Finally, this particular QBO permutation (similar to this year) has only occurred two times since the late 1970s, namely, a +QBO descending at 30mb while the easterly -QBO at 50mb maintained. Those two years were nina like, with amplified intra-seasonal signals. One of those winters was one of the worst winters on record snowfall wise in our local area. 

 

>>>>

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2 minutes ago, psuhoffman said:

like Bob says, somethings the weather just weathers...

obviously there is a causation but we do not understand every detail to to every finite level...and it is possible the causation is linked to various very small sensitive effects and not just one or two major ones making it much harder to identify why thing's aren't going according to expectations. 

We're still a long ways away from consistently accurate long range forecasting. Applies to winter, spring, summer, and fall. Sometimes forecasts nail it and sometimes they bust horribly. It's unfair to expect anything more than that for the rest of our lives on the planet. Anyone who bashes long range forecasting has way too high of expectations on what the science is capapble of. I only focus on 2 week patterns and that is fraught with curveballs and unexpected outcomes. 2 month leads? Lol. Yea, expecting accuracy there on a regular basis is flat out unrealistic. 

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11 minutes ago, Maestrobjwa said:

See and the fact that nobody seems to be able to figure out what the heck has been going on this winter really bothers me. How is it after all these decades of data...that this winter is somehow different from the rest in terms of it utterly baffling even the best met minds? Somebody gotta figure out something! That's what has made this winter mentally taxing at times--nothing seems to be working the way it should (resulting in both good and bad outcomes). It's not just our usual "missing a threat" like a bad track or something...but just the entire bigger picture. All winter it's been "well this usually does this, by why it didn't we don't know". I do hope after this season mets will take a long hard look so that maybe we don't have to go through this as much. End rant...

Russian atmospheric collusion 

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1 minute ago, frd said:

Seems when you look at the QBO for this winter we have a rare occurence. First time I heard of this combination taking place. @Isotherm was talking about things this morning.

He states there are several things at play in regards to why we have not seen the typical responses including the blocking.

I  brought over this section from his detailed update over , since we had touched on the QBO earlier. 

His entire post covers a lot more, and is over at 33andrain.   

 

He states :  

<<<

 

 Finally, this particular QBO permutation (similar to this year) has only occurred two times since the late 1970s, namely, a +QBO descending at 30mb while the easterly -QBO at 50mb maintained. Those two years were nina like, with amplified intra-seasonal signals. One of those winters was one of the worst winters on record snowfall wise in our local area. 

 

>>>>

Wonder which two winters he was referring too? (wasn't 1978/79 was it? Lol)

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4 minutes ago, psuhoffman said:

like Bob says, somethings the weather just weathers...

obviously there is a causation but we do not understand every detail to to every finite level...and it is possible the causation is linked to various very small sensitive effects and not just one or two major ones making it much harder to identify why thing's aren't going according to expectations. 

MJO has become a big driver of this winter, but to me I'm starting to question why/how the PNA has remained so persistently unfavorable, in spite of several attempts at models showing more +PNA looks?  

IMO those 2 tellies have been the wreckin ball here in the east.  

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Here is that entire post from Isotherm , silly just to provide a few sentences on second thought.  

Great post, thanks Tom ! 

Science is all about advancement, usually due to anomalies that emerge spontaneously in any given dataset. Most scientific advancement occurs not as a function of status quo, but because something atypical, aberrant has arisen in any given field, and the scientists who are independently minded (and financed) enough to pursue those anomalies, are generally the ones who pioneer and "break ground."

 

Before I get into this, just as a disclaimer: it is still entirely possible that there's a "late-game comeback" with respect to this winter, but, it is apparent enough to me at this point, that the winter deserves/warrants a re-analysis post of sorts, regardless of how we finish over the next month, which may or may not ameliorate the widespread busts of this winter. 

 

Over the past few weeks, I've used some time to investigate, and believe I have a cogent hypothesis regarding the failings of this winter. In retrospect, I am rather disappointed in myself, being one who tries to be as meticulous as possible in research, that I missed this; however, it's easier to say such in hindsight, and I may not have detected this, but for the miscalculations of this winter.

 

We had quite a bit of +AAM in the atmosphere this winter, but I think to some extent, in not exactly the "right" places, to induce the necessary countervailing easterlies in the high latitudes. The lack of FT cooperation courtesy of the meager Nino forcing was a major factor, which would have produced more sub-tropical westerlies / +AAM, initiate the STJ, form sub-tropical TROUGHS, and thereby weaken the polar jet. We have had a lot of sub-tropical RIDGES this winter, more La Nina like. 

 

I do strongly believe the issues with respect to this winter's failures goes even deeper. Retrospectively, the tropical forcing pattern during much of autumn 2018 more closely resembled a La Nina, w/ subsidence large-scale over the Pacific, and more uplift over the Indian Ocean. This did attempt to flip somewhat in November, which is partially what led me down the putative rabbit's hole, prior to reversing back toward a Nina-esque tropical forcing regime in December. This was an aberration year in which November's regime certainly did not augur the mean winter pattern.

 

Additionally, the positive 30mb QBO hurt us and destructively interfered more than anyone thought in my opinion. We were expecting that the -50mb QBO, which has high correlation to SSW events (that truly helped!) would countervail. Unfortunately, yes, the negative 50mb QBO produced a SSW, but it also tends to intensify the MJO/intraseasonal signal.

 

Along that vein, I actually think this winter was too UNSTABLE in a number of ways. The MJO simply did not cease: constant propagation from amplified phase to phase, obviating any stable PNA or cold pattern from becoming locked in, compared to winters in which we stabilize in the colder MJO Nino phases. The negative 50mb QBO and thereafter the massive SSW only aided further to augment the incessant MJO signal.

 

Then, the 30mb QBO, which I now think is really more important than the 50mb QBO, aided in stabilizing the tropospheric polar vortex, and decreasing the very necessary tropospheric receptivity to blocking. The unpropitious 30mb QBO, the negative 50mb QBO induced intraseasonal amplification, unstable MJO, and Nina-esque forcing, precluding FT cooperation, sub-tropical +AAM, sub-tropical troughs, and polar easterlies -- were all the factors in my opinion.

 

Furthermore, the negative 50mb QBO, coupled with the cooling tropical stratosphere as a function of the major SSW event (I have noted this before), and the abnormally warm off-equator SST's in the West Pacific, aided in expanded hadley cells, poleward / retraction of the northern stream, yielding a less amplified, more disconnected, Nina-esque type of paradigm. Further, the very cold tropical stratosphere led to a convective disarray, much like a low-cap T-storm day, wherein destructive interference from rossby waves, and MJO amplification in the warm phases was frequent. 

 

The NAO has been trying to go negative this season, evincing pretty positive geopotential heights over Greenland, but the Azores/sub-tropical high never departed, which has kept the NAO calculation technically slightly positive thus far. I think that's Nina-forcing and QBO induced largely. Notice in the below composite, and you'll see even on model data going forward, we try to achieve the higher heights in Greenland, but it doesn't DISCONNECT and DETACH from the Azores sub-tropical high, thus, Europe remains mild, rather than the classic undercutting jet -NAO signal.

 

f57k9x.jpg

 

 

Regarding the AAM point; this is a highly unpropitious / unfavorable diagram right now, if you're looking for high latitude blocking of significance. +AAM in the wrong places. The belt of easterly/-AAM deposits in the sub-tropics tends to induce more nina-esque sub-tropical ridges, and indirectly, intensify the polar jet, tending to countermand sustained blocking.

 

http://gsdmsolutions.com/~gsdm/clim/daily_total/glaam.sig.90day.gif

nfjwcj.gif

 

That needs to alter for any major blocking to occur.

 

Finally, this particular QBO permutation (similar to this year) has only occurred two times since the late 1970s, namely, a +QBO descending at 30mb while the easterly -QBO at 50mb maintained. Those two years were nina like, with amplified intra-seasonal signals. One of those winters was one of the worst winters on record snowfall wise in our local area. 

 

Now, with all that being said, these are hypotheses, and correlations, with arguably debatable causation chains, but evidence of causality in meteorology is quite difficult as it's nearly impossibly to control for confounders and isolate the pertinent variables. Nevertheless, I am satisfied with re-analyzing this winter, and I will certainly not make this particular mistake again.

 

As far as the remainder of this winter: the WWB looks good, as does the MJO propagation, but will the atmosphere respond? Or will the Nina-esque tendencies w/ atypical AAM distribution, and dichotomous QBO keep the blocking muted? That seems to be what models are currently indicating.

 

Like I said, there is a chance for a late-game "save," and then, hopefully, all of the above will simply be good, abstract discussion regarding my take-aways going forward. On the other hand, if there isn't a late game save, the above is effectively a post-mortem on the issues underpinning this winter's miscalculations by virtually everyone if not everyone in the meteorological community this winter.

 

Thanks for reading.

 

Tom

Added this paragraph into the above:

 

A short summary of the problems: The Pacific was the largest problem; stronger blocking would have countervailed, but that wasn't the principal issue. The AO will average slightly negative for the winter, and the NAO probably near neutral to slightly positive. It was the pacific - due to reasons expounded above, and secondarily, the lack of more effective blocking, intraseasonal amplification / hadley cell expansion, due to the SSW and QBO as well as SSTA profile.

 

 

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4 minutes ago, frd said:

Seems when you look at the QBO for this winter we have a rare occurence. First time I heard of this combination taking place. @Isotherm was talking about things this morning.

He states there are several things at play in regards to why we have not seen the typical responses including the blocking.

I  brought over this section from his detailed update over , since we had touched on the QBO earlier. 

His entire post covers a lot more, and is over at 33andrain.   

 

He states :  

<<<

 

 Finally, this particular QBO permutation (similar to this year) has only occurred two times since the late 1970s, namely, a +QBO descending at 30mb while the easterly -QBO at 50mb maintained. Those two years were nina like, with amplified intra-seasonal signals. One of those winters was one of the worst winters on record snowfall wise in our local area. 

 

>>>>

 

 

Frd - my full post is over on my winter outlook thread on the main board here as well, if anyone is interested.

Re: those specific years - yes, extremely rare permutation. The only two years like this one as far the QBO dichotomy since the late 70s were: 1994-95, and 2001-02. Both of which were quite appalling snowfall wise. Obviously, no year is like, but those similarities in Pacific systemic issues and failed propagation / high magnitude tropospheric blocking were there. Again, there's a chance for a late-game save, but enough has happened to warrant a re-analysis of the widespread miscalculations, in my view, by everyone. The Pacific was the principal problem (AO will finished slightly negative, NAO probably near neutral/slightly pos); stronger blocking could have countervailed. Reasons are expounded in my post on the main board thread.

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4 minutes ago, Isotherm said:

 

 

Frd - my full post is over on my winter outlook thread on the main board here as well, if anyone is interested.

Re: those specific years - yes, extremely rare permutation. The only two years like this one as far the QBO dichotomy since the late 70s were: 1994-95, and 2001-02. Both of which were quite appalling snowfall wise. Obviously, no year is like, but those similarities in Pacific systemic issues and failed propagation / high magnitude tropospheric blocking were there. Again, there's a chance for a late-game save, but enough has happened to warrant a re-analysis of the widespread miscalculations, in my view, by everyone. The Pacific was the principal problem (AO will finished slightly negative, NAO probably near neutral/slightly pos); stronger blocking could have countervailed. Reasons are expounded in my post on the main board thread.

Thanks... What do you think is the main cause of the SE ridge and inability to get a PNA ridge on guidance despite -soi and MJO phase 8?  Error or time to admit its just not happening this year, even if we finally get the pacific forcing right?

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5 minutes ago, psuhoffman said:

Thanks... What do you think is the main cause of the SE ridge and inability to get a PNA ridge on guidance despite -soi and MJO phase 8?  Error or time to admit its just not happening this year, even if we finally get the pacific forcing right?

 

The atmosphere is behaving much more akin to neutral ENSO rather than El Nino this winter, so I would discard the z500 composites for MJO/Ninos evincing the favorability in the p7-8 transition. However, once we're into the core of phase 8 in a couple of days, with strengthening near 8/1 threshold, that effect will manifest with the typical circa 7 day lag. So I expect guidance will finally trend more favorable with the PNA ridging after about February 22nd or so. The MJO wave is more slow-moving and amplified than usual as well, so the effects are enhanced as far as Western trough. Typical MJO progression is faster, but this has been the winter of interference from other tropical waves. Like I said, that post wasn't a total post mortem, and hopefully it will become abstract, especially for you all in the MA who are nearing normal already.

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4 minutes ago, Isotherm said:

 

The atmosphere is behaving much more akin to neutral ENSO rather than El Nino this winter, so I would discard the z500 composites for MJO/Ninos evincing the favorability in the p7-8 transition. However, once we're into the core of phase 8 in a couple of days, with strengthening near 8/1 threshold, that effect will manifest with the typical circa 7 day lag. So I expect guidance will finally trend more favorable with the PNA ridging after about February 22nd or so. The MJO wave is more slow-moving and amplified than usual as well, so the effects are enhanced as far as Western trough. Typical MJO progression is faster, but this has been the winter of interference from other tropical waves. Like I said, that post wasn't a total post mortem, and hopefully it will become abstract, especially for you all in the MA who are nearing normal already.

Thanks. Yea I abandoned the “Nino plots” a while ago (although the current soi drop has me hold out some hope). But like you said the phase 8/1 neutral is a good look also and by Feb 25+ we should start feeling that affect.  I’ve been sticking too that but man I would like to see the guidance come around soon!  I guess it has made a couple fairly significant shifts at medium leads this winter already so why not again when it sees the mjo influence?

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And this is why the EPS looks like crap... if there are other negative influences, such as isotherm talks about...this might not be enough of a signal to overcome that.  The forcing certainly is located in the right places but the wave is weak sauce...figure that after an amped up ape mjo through warm phases all winter it would become a wimp when it finally makes it into cold phases.  lol

ECMF_phase_MANOM_51m_small.gif.e74e746366b857ee261e0fc62d2357e2.gif

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GFS looks like a good hit incoming at 162.  Its slower, but seems to be throwing more precip into the cold.

 

Edit: Ehh. Don't forcast model runs.  It ends up with less precip but looks to stay mostly snow.

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with the trend away from strong HP in front we probably need a weaker storm at this point.  Something amplified probably creates too much southerly flow and we go to rain.  Not even sure ice anymore given the trends in the thermal profile the last 24 hours.  But there is still room for it to work out if we get tight spacing and weaker waves.  

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2 minutes ago, psuhoffman said:

with the trend away from strong HP in front we probably need a weaker storm at this point.  Something amplified probably creates too much southerly flow and we go to rain.  Not even sure ice anymore given the trends in the thermal profile the last 24 hours.  But there is still room for it to work out if we get tight spacing and weaker waves.  

it will probably end up a further south version of what you just experienced earlier this week...which is fine..few inches of snow then ice or something like it... but that deep CAD signature and historic ice storm seems outlier now...but who knows

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6 minutes ago, psuhoffman said:

with the trend away from strong HP in front we probably need a weaker storm at this point.  Something amplified probably creates too much southerly flow and we go to rain.  Not even sure ice anymore given the trends in the thermal profile the last 24 hours.  But there is still room for it to work out if we get tight spacing and weaker waves.  

Yea...Gefs has been trending less amplified the last few runs so maybe a good thing . Haven't looked at Eps though

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2 minutes ago, losetoa6 said:

Yea...Gefs has been trending less amplified the last few runs so maybe a good thing . Haven't looked at Eps though

It's also backing off on the northern stream low tracking across the lakes above it. This was creating weakness and helping allow midlevels to warm easily. The low is barely there on this run. 

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42 minutes ago, psuhoffman said:

And this is why the EPS looks like crap... if there are other negative influences, such as isotherm talks about...this might not be enough of a signal to overcome that.  The forcing certainly is located in the right places but the wave is weak sauce...figure that after an amped up ape mjo through warm phases all winter it would become a wimp when it finally makes it into cold phases.  lol

ECMF_phase_MANOM_51m_small.gif.e74e746366b857ee261e0fc62d2357e2.gif

If the EPS is the most reliable model for the MJO, then this is really bad news. Is it naive to hope for something closer to the CFS look?

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2 minutes ago, Bob Chill said:

It's also backing off on the northern stream low tracking across the lakes above it. This was creating weakness and helping allow midlevels to warm easily. The low is barely there on this run. 

That's a good development.

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5 minutes ago, losetoa6 said:

Yea...Gefs has been trending less amplified the last few runs so maybe a good thing . Haven't looked at Eps though

Don't, it was depressing.  Weaker wave but also pushed the thermal boundary way north so it was mostly just rain or ice without much snow anywhere, even north of us.  

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5 minutes ago, Bob Chill said:

It's also backing off on the northern stream low tracking across the lakes above it. This was creating weakness and helping allow midlevels to warm easily. The low is barely there on this run. 

I kind of like the way the GFS is heading...its losing the "big storm" potential but evolving towards a way we can score a simple moderate snow.  I am totally fine with that.  But need to see euro go that way.  

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6 minutes ago, Fozz said:

If the EPS is the most reliable MJO forecaster, then this is really bad news. Is it naive to hope for something closer to the CFS look?

yes, but its not out of the question to expect a compromise between the more amplified GFS/CFS camp and the euro.  The CMC is kind of in the middle...even if the compromise is 70/30 towards the euro that would still be a good look...just get that wave out of the COD into decent amplitude.  

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20 minutes ago, psuhoffman said:

I kind of like the way the GFS is heading...its losing the "big storm" potential but evolving towards a way we can score a simple moderate snow.  I am totally fine with that.  But need to see euro go that way.  

dude--i dont   want a moderate storm. I liked it way before where it was heavy snow 4 inches and killer ice. The event verbatim right now is not even worth tracking

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