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WxUSAF

Winter 2019-20 Preseason Discussion

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2 hours ago, WxUSAF said:

Cohen says snowcover advance index supports -AO! Here we go!!!

 

#sarcasm

while that may be a bit leading/presumptuous....I'd sure rather have explosive snowcover than warm barren tundra.

#maybemaybenot 

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Hey weenies, figured it would be exceptionally strange for me to not post in the winter thread during Oct so....

TL:DR: Favorable enso is close to off the table. I have no ides if the AO/NAO will cooperate. The north Pac ssta's are moving in the direction of what we want to see but plenty of work to do over the next month. This could be a sign that the Pac jet won't destroy our hopes and dreams and there's no reason at all to think we're F'd yet. My confidence in any outcome is very low still.

I have no opinion on QBO/blocking/strat PV etc yet but I am warming up to the idea that this winter may not be a total disaster. Enso probably won't drive the bus as it's pretty late and the enso regions are ambiguous imo. Numerical data for region 3.4 looks ok but I'm more of a visual person when assessing the influence of the eq Pac and right now it just doesn't look all that great. Region 3.4 warmth seems more of a byproduct of the pac having expansive warmth north of the equator in general and not due to circulation patterns responding to nino forcing.

In early Sept I thought the pac nino and pdo regions looked like trash. This is not a ssta map that inspires confidence in a good winter in the mid atlantic:

 

anomnight.9.2.2019.gif

I havent been paying much attention to what others have been saying but if enso isn't going to do much then the next best thing is to have a +PDO. The PDO is what helped make the 2013-16 winters favorable. It may have been the primary reason. Hard to say. It's also what made 95/96 a prolific nina. A +pdo during a nina is very uncommon. Especially a mod+ Nina. When I looked at the ssta map in early Sept my first thought was the PDO region looked like crap. Not as bad as a -pdo but pretty bad.

Over the last 2 months the PDO region has improved. Not as fast as I'd like but it's better. The area off the coast of Japan needs to cool down but you can see the expanding region of BN ssta's in the western pac compared to early Sept. Hopefully that keeps building eastward. It could be the first clue as to what the predominant pac jet structure ends up being this winter.anomnight.10.31.2019.gif

 

We only have 14 real weeks of winter and it goes quick. As we've seen recently and countless times in the past, the pac jet is a big deal here and get it wrong for a month and you can kiss half or more of winter goodbye regardless of all other indices. The problem is there is no way to know what the jet is going to do weeks or months in advance. Especially during transition months like Nov and early Dec. However, if Nov features a trough in the west pac and a ridge in the east pac centered near the west coast it's going to push the pdo region into a configuration that can be really friendly here. It would also increase our chances of getting off to a good start in early Dec. If there is a persistent good pac pattern in Dec it's entirely possible it will recur throughout met winter. 

It's a chicken or egg argument though just like "the blob" in 2013-15. What causes what? Do the ssta temps force the troposphere or does the trop force the ssta's? IMO it's a little bit of both. Weather patterns force the ssta's and once the warm and cool anomalies are well established they can assist with persistance. 

Gun to head this winter will be close to average in both temps and snowfall and the odds of +climo snowfall are slightly higher than an epic fail. I'm expecting the -EPO to flex at times and I doubt we'll get SE ridged to death.

 

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Good to see you, friend. Seems like this winter could feature many of the things we’ve seen a lot this decade. -EPO driven cold shots, predominantly +NAO, variable AO, and moisture around. So like most winters this decade, we probably will get a lot of nickels and dimes and maybe if we’re lucky a Susan B. Anthony or two.

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10 minutes ago, WxUSAF said:

Good to see you, friend. Seems like this winter could feature many of the things we’ve seen a lot this decade. -EPO driven cold shots, predominantly +NAO, variable AO, and moisture around. So like most winters this decade, we probably will get a lot of nickels and dimes and maybe if we’re lucky a Susan B. Anthony or two.

No Barber Dimes, Wheaties, Benjamin Franklin and Walking Liberty Halves?

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53 minutes ago, jaydreb said:

Oh boy, must be close to showtime if Bob is here.  Great to have you posting @Bob Chill!  

I haven't paid much attention to long range this year honestly. Since there's no obvious "easy signal" so far I'm not into winter mode yet. First good looks at reasonable leads will get me back into it

49 minutes ago, WxUSAF said:

Good to see you, friend. Seems like this winter could feature many of the things we’ve seen a lot this decade. -EPO driven cold shots, predominantly +NAO, variable AO, and moisture around. So like most winters this decade, we probably will get a lot of nickels and dimes and maybe if we’re lucky a Susan B. Anthony or two.

Yea, we can luck into a big storm any year but no reason to think we'll have a juiced stj and blocking yet. This year seems kinda boring leading in. I don't have high expectations. Would like to see the atlantic behave better early on. It's been what... 9 years since had a persistent favorable atlantic in DJF?

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11 hours ago, MountainGeek said:

Thanks -- don't forget to mix in general atmospheric chaos/butterfly effect, a VERY short recorded data timespan (relative to all of past history).....trying to predict longer term and seasonal weather has lot of parallels to picking numbers or trying to "game" a slot machine. Quite a few of the folks who participate in this forum enjoy hitting the casino as well...I don't think that's a coincidence. And the nice thing about weather is when it pulls the rug out from under you, you only suffer a hit to your pride and not your pocketbook. :D

Fine analogy, however after the rug it all depends on where, who, or what you land on. As always

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If the UKmet couldn't forecast the seasonal NAO last winter, even after doubling down in November, how the hell can this trash model even attempt a seasonal forecast and for 4  months in a row as well of a + NAO ?  

Wait, persistence is modeled into the physics.   

It does have company,  but many models last Fall called for a -NAO average during the winter.  I don't buy it yet.   

 

 

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31 minutes ago, frd said:

If the UKmet couldn't forecast the seasonal NAO last winter, even after doubling down in November, how the hell can this trash model even attempt a seasonal forecast and for 4  months in a row as well of a + NAO ?  

Wait, persistence is modeled into the physics.   

It does have company,  but many models last Fall called for a -NAO average during the winter.  I don't buy it yet.   

 

 

I think that model should be banned from being posted on these forums.

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This makes a lot of sense and goes along with some of the mets I follow. 

The talk from some of them, including HM here is that "if" the seasonal models are indeed getting the winter NAO signal from forecasting and anticipating a strong to very strong PV, well,  if the vortex if weaker, or more prone to shifts and elongations then the seasonal call for a mostly + NAO during December through Feb. might be very wrong.  Taken a step further would potentially equate to a very different sensible weather outcome for some folks. 

Please keep in mind HM is talking about the AO and I am inferring the association to the NAO domain and the relationship of a not so strong PV. 

 

 

 

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1 hour ago, frd said:

A most interesting set-up in terms of the warming origins.

 

 

Been watching that for the last week or so. Almost posted something this morning on it. Euro (WB doesn't have 10 mb-50 mb for the EPS) has a similar setup at 240 hrs as the GEFS though the warmth on the Russian side is displaced somewhat farther south. So one could maybe guess that it would have a somewhat similar evolution beyond hour 240? Like seeing the top down heating as well as the wave two action and did find the placement of the heating in the N Atlantic strange as well. Not seeing much in the way of disturbance nor displacement with the pv on the models as of yet but would not be surprised as that period of time nears that the models start picking up on it and/or shortly after the end of the extended. Even if we don't see a response from the pv one can be assured that this 1, 2 punch is having an impact on the pv. Now what does all this mean for possible sensible weather for our region? No idea, especially with seeing the warmth over the N Atlantic.

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21 minutes ago, showmethesnow said:

Even if we don't see a response from the pv one can be assured that this 1, 2 punch is having an impact on the pv. Now what does all this mean for possible sensible weather for our region? No idea, especially with seeing the warmth over the N Atlantic.

Nice seeing some pressure being applied on the PV to keep it from rapidly getting stronger.  As HM stated,  you simply can not go by the last days of October and early November, in regards to the PV strength, as a proxy to the implications for the ensuing winter.  

Also seems we are taking a different approach this late Fall with the location of the PV and the general behaviors in the HL. 

Some similarities later next week if we get a significant snow storm to our North, but feeling that does not gloom the winter coming up. 

Also, looking back at the summer in the Northern Plains and continuing even now with the placement of the coldest anomalies, well they seem to want to take shop on our side of the pole. Not seeing any red flags so far with the MJO. and nice seeing the + PNA kick up.      

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@showmethesnow I brought up the record +PMM a month or so ago. Rolling forward from Sept. to November and then December a very high +PMM  gives a decent signal for a cold November in the East , and a even more robust cold signal for December.  I even recall it has, in December,  the ability to help in phasing and in introducing a more active and present STJ stream, through longer wavelengths, .

Not saying it is going to work out, because about 90 % of mets are going with a warm December this year. I feel we can go normal with colder risks and stormier as well.   

BAMMWx so far is on a roll. 

 

 

 

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On 10/31/2019 at 8:46 PM, Bob Chill said:

Hey weenies, figured it would be exceptionally strange for me to not post in the winter thread during Oct so....

TL:DR: Favorable enso is close to off the table. I have no ides if the AO/NAO will cooperate. The north Pac ssta's are moving in the direction of what we want to see but plenty of work to do over the next month. This could be a sign that the Pac jet won't destroy our hopes and dreams and there's no reason at all to think we're F'd yet. My confidence in any outcome is very low still.

I have no opinion on QBO/blocking/strat PV etc yet but I am warming up to the idea that this winter may not be a total disaster. Enso probably won't drive the bus as it's pretty late and the enso regions are ambiguous imo. Numerical data for region 3.4 looks ok but I'm more of a visual person when assessing the influence of the eq Pac and right now it just doesn't look all that great. Region 3.4 warmth seems more of a byproduct of the pac having expansive warmth north of the equator in general and not due to circulation patterns responding to nino forcing.

In early Sept I thought the pac nino and pdo regions looked like trash. This is not a ssta map that inspires confidence in a good winter in the mid atlantic:

 

 

I havent been paying much attention to what others have been saying but if enso isn't going to do much then the next best thing is to have a +PDO. The PDO is what helped make the 2013-16 winters favorable. It may have been the primary reason. Hard to say. It's also what made 95/96 a prolific nina. A +pdo during a nina is very uncommon. Especially a mod+ Nina. When I looked at the ssta map in early Sept my first thought was the PDO region looked like crap. Not as bad as a -pdo but pretty bad.

Over the last 2 months the PDO region has improved. Not as fast as I'd like but it's better. The area off the coast of Japan needs to cool down but you can see the expanding region of BN ssta's in the western pac compared to early Sept. Hopefully that keeps building eastward. It could be the first clue as to what the predominant pac jet structure ends up being this winter.

 

We only have 14 real weeks of winter and it goes quick. As we've seen recently and countless times in the past, the pac jet is a big deal here and get it wrong for a month and you can kiss half or more of winter goodbye regardless of all other indices. The problem is there is no way to know what the jet is going to do weeks or months in advance. Especially during transition months like Nov and early Dec. However, if Nov features a trough in the west pac and a ridge in the east pac centered near the west coast it's going to push the pdo region into a configuration that can be really friendly here. It would also increase our chances of getting off to a good start in early Dec. If there is a persistent good pac pattern in Dec it's entirely possible it will recur throughout met winter. 

It's a chicken or egg argument though just like "the blob" in 2013-15. What causes what? Do the ssta temps force the troposphere or does the trop force the ssta's? IMO it's a little bit of both. Weather patterns force the ssta's and once the warm and cool anomalies are well established they can assist with persistance. 

Gun to head this winter will be close to average in both temps and snowfall and the odds of +climo snowfall are slightly higher than an epic fail. I'm expecting the -EPO to flex at times and I doubt we'll get SE ridged to death.

 

 

Welcome back from summertime "hibernation", Bob!  I'm rubbing my eyes and waking up myself as we get into November now!  Always good to see your thoughts, regardless of how the conditions are, thanks again for your level-headed discussion and insights.  I guess this winter will be a "wait and see" how things turn out, especially if the ENSO state perhaps won't be so much of a driving factor.  I think what you say here is about as much as one can infer at this point.  Some good periods of -EPO would be nice, and not having the SE ridge of death for weeks on end would surely help.  I don't think we'll revisit the amazing fortune of 2013-14 (that was in a special class by itself), but if we can even get in that ballpark, it would make for some interesting times.  I'm not looking for epic-ness, but some interesting solid events to follow and score on would be a win.  Last year was strange...so much relative "hype", and I'm still not sure why various indices and model projections seemed so "off" even in the medium range.  But even with that, at least speaking from a DC-metro-centric point of view, we still did halfway decently, all things considered (early snow in Nov., the Jan. event, some solid cold around then as well, plus the snow in mid-Feb).

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7 hours ago, C.A.P.E. said:

QBO 30mb equatorial zonal wind continues to head towards neutral- but its doing so slowly. Oct value was 7.27, down from 8.25 in Sept. Moving in the right direction at least.

I kept hearing the word "zonal" last winter...that's one of the things that plagued us last winter, wasn't it?

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6 hours ago, Maestrobjwa said:

I kept hearing the word "zonal" last winter...that's one of the things that plagued us last winter, wasn't it?

Completely different context. QBO monitors the periodic shift in the zonal wind in the tropical stratosphere. These winds periodically shift between westerlies and easterlies. The easterly phase is associated with a weakening SPV, and potentially the development of HL blocking.

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Really a lot to like with what we are seeing on the GFS/GEFS/Euro/EPS through the extended. If the models are somewhat right and are showcasing the general base state (after any relaxes) as well as some key features being presented it bodes well for the first half of winter where I would not be shocked to see us reach our seasonal averages by the first of the year.

Thought I would break down the things I am seeing at this time. Below is the 10 day mean (day 6-16) on the GEFS. This is pretty close to fulfilling my wish list for our snow chances. Trough in the east, ridging in the west. -EPO with an Aleutian trough. +PNA overcutting a weakness/troughing in the SW. Ridging into Greenland  with an active PV centered over the Hudson Bay. Now this look is rock solid throughout the 16 days on the GEFS. This fact gives a strong argument that this may be base state we see for the foreseeable future. And with one exception the EPS mirrors what we are seeing on the GEFS. The one exception is that the EPS relaxes the pattern for 3 days or so at the end of extended. What is noteworthy about that though is that at the very end of the extended you can see the EPS snapping back quite quickly to the general look below. This fact also gives a strong argument that this look may be the base state.

 

GEFS500s5-15daymean.thumb.gif.4f5cf7fe251e323dfdcaac36cc7e7475.gif

Now I thought I would break things down even farther from what we see in the general pattern above.

Lets look at what we are seeing around Alaska. The -EPO and the Aleutian troughing are creating a split flow in the upper latitudes. This is creating a polar jet overriding and dropping down the east side of the ridging delivering cold. Within this jet we are seeing quite a bit of energy streaming down within it as well. Now when we look at the Aleutian trough we are seeing a constant stream of lows rotating around that trough. These lows are interjecting quite a bit of energy into the PAC flow as it enters the CONUS.These lows are also accomplishing one other thing that I will go into a little later. So what we have here is cold air delivery along with plenty of energy for possible storm development into a favorable trough/ridging setup through the CONUS for the east. 

 

935213456_Alaskasplitflow.thumb.gif.6fb40fba50538bc1a46eb1a54be5906f.gif

 

 

Now let's see what we have in central Canada and into the NAO domain. We are seeing an active PV that has plenty of energy rotating around it and it is generally centered over the Hudson Bay which is a favorable local for the East Coast. We are also seeing ridging popping into Greenland. Now what is appetizing about this is that anyone of these pieces of energy rotating around the pv has a chance of blowing up and creating a NAO/50/50 block (that is if the PV itself doesn't rotate there because it is doing a lot of gyrations). Needless to say this combo can produce some of our bigger storms.

PV.gif.1945cccb3568eb6816fd3cfd7fa921f9.gif

 

Now let's move over to the PAC into the 250 mb region where the jets lie. This is just a snapshot of a period of time that shows several features going on. I used the GFS as to it gives more clarity/detail to the features that get lost with the watering down we see on the ensembles. Note that some of these features are popping up here and there throughout the 16 days. First off we have a strong jet straight jet entering the Pacific. Not really what we want to see if you recall last year. But we are seeing a significant difference here. This PAC jet is undergoing an onslaught from the constant stream of lows (one is circled in blue below) that are rotating around the Aleutian trough. These are effectively disrupting and diffusing the jets energy and sending it in all directions. Also of note though not shown at this period of time, we are seeing an on again/off again split flow setup in the SW and just off the coast as lows rotate/form in the general region where a weakness/troughing was noted before. This split flow provides the opportunity of a tropical jet popping up during these times (drew an arrow for where the tropical jet sets up but it is not present at this time). One feature I have been interested in and keeping an eye on for the last couple of weeks is what we are seeing in the Gulf/Yucatan/Mexico region. What we have been seeing is a pretty steady state anticyclonic rotation that has been planted somewhere through that general region for some time now. This is actually a very promising feature as it opens the gulf up to possibilities as well as helps to promote the lifting of any southern/tropical jet northward in the east. Also of note with this feature is that we have seen a tropical jet pop up several times already around this feature that has been detached from the one that we would typically see coming from central Pacific/Hawaii (Pineapple express). This jet is actually being pulled from the deep south (close to the equator) and being rotated up and around the anticyclone in the upper levels. 

Jet.thumb.gif.9b4e0ca721016f94b44f34d1bde665a8.gif

 

Now one final map to hopefully drive home the potential we see with this pattern. Again will go with a snapshot of the GFS. Look at all the energy we see streaming everywhere. We see pieces rotating around the PV in Canada. We see them in the NS riding down the EPO ridge over Alaska. We see energy riding in on the PAC jet. We see energy coming in on the southern stream from the central Pacific and we see energy riding up from the equator around the anticyclone in the upper levels around the Gulf. And all of this energy is directed into a trough in the east. This look provides many ways to score from nickels and dimes to big ticket items and anything in between.

 

Energy.thumb.gif.f20a3a0db4307578419f3af60a38104e.gif

Now if we were a month later in the season I would be somewhat confident putting good money on us seeing measurable if not noteworthy snowfall probably for a good portion of our region if the GEFS were to verify the next 16 days. As it is, I think many will see their first flakes of the year with the favorable locals maybe cashing in somewhat. Again, if the GEFS is somewhat accurate with what it is presenting at this time. I guess tracking season has now officially begun as far as I am concerned.

 

 

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Like last winter I would keep an eye on the ENSO region 1.2 

If region 1.2 were to warm significantly I believe it could overwhelm the pattern for us here in the East in a negative fashion, and lead to warmth and a poor storm track. 

There are many favorable elements that are pointing to cold and snow,  but I prefer we remain in the SST profile that we have basically have maintained the last several months in Pac.  

If BAMMWX is bringing up the potential warming of ENSO 1.2 as a possible concern it gets my attention. 

This of course goes with the notion that most of us here know that region 1.2 is prone to wild short-term fluctuations.   

 

Niño Regions

 

 

 

 

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Great writeup ShowMe.  Really appreciate your analysis, the explanation of the variables involved, and the laymen's terms a mere mortal weenie wanabe like me can follow.  

The UL rotation around the GOM and Yucatan relates to the nearly tropical DPs we had here last week in advance of the front that came through.  If the trough can bring down something along the eastern front of the Rockies and tap into that moisture at the same time the STJ reappears, it would seem we'd have the chance for a phased event.  The SSTs along the OBX are still pretty warm to help fuel anything that spins up the coast and the WAR seems to have migrated far enough to the East that it won't kick something west of us.   All of this is probably wishful thinking, but after last year and the year before, if wishing helps I'm all for it. 

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7 hours ago, JakkelWx said:

Looking like it's gonna be an awesome winter! @showmethesnow great write up! Let's hope this winter doesn't fail like last year.

That seems a bit harsh for a winter where 2/3 airports beat average and most in this forum got above median snowfall.  It was a letdown because of inflated epic expectations. Taken alone it was better than 60-70% of our winters in many locations. 

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13 minutes ago, psuhoffman said:

That seems a bit harsh for a winter where 2/3 airports beat average and most in this forum got above median snowfall.  It was a letdown because of inflated epic expectations. Taken alone it was better than 60-70% of our winters in many locations. 

I meant to say that tbh. I stand corrected. With that said I'll have my doubts even if the euro weeklies show persistent -NAO/-AO this year because of last year's fiasco. Almost all the time, exaggerated and epic expectations lead to the winter failing to meet those expectations. My apologies, I sounded a little vague

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1 hour ago, JakkelWx said:

I meant to say that tbh. I stand corrected. With that said I'll have my doubts even if the euro weeklies show persistent -NAO/-AO this year because of last year's fiasco. Almost all the time, exaggerated and epic expectations lead to the winter failing to meet those expectations. My apologies, I sounded a little vague

No apologies necessary.  It’s all friendly conversation.  WRT last season the long range guidance continuously mishandled the forcing in the central and western pacific and so it continuously got the effects wrong in the long range. They kept going to typical modoki Nino looks but reality didn’t. 

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2 hours ago, psuhoffman said:

That seems a bit harsh for a winter where 2/3 airports beat average and most in this forum got above median snowfall.  It was a letdown because of inflated epic expectations. Taken alone it was better than 60-70% of our winters in many locations. 

DCA, right?

I wasn’t here obviously last season but much of this winter enjoyment stuff is fundamentally subjective, not objective, and an expectations game.

It’s not as if it was just one model leading most astray, it was across the board. The potential didn’t really materialize aside from a time or two. It happens I guess lol. 

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