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October/November 2019 Mid/Long Range


mattie g
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44 minutes ago, WxUSAF said:

We don’t need a SSW anytime soon. Just keep the strat vortex weak and keep beating on it and that’s fine.

Wouldn't an early strat-warm actually work to our detriment?  Correct me if I am wrong, but it seems like the best time for full-scale strat-warm's is around mid-winter or so in order to "keep the party going."

Agreed though: Don't let that PV get too comfortable!

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We had one last year around New Years, which seems like an ideal time to maximize peak climo, and it didn’t propagate downward and substantially change the tropospheric AO. I wouldn’t want a SSW in November or most of December, but anytime after that is good probably. 

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7 minutes ago, Eduardo said:

Wouldn't an early strat-warm actually work to our detriment?  Correct me if I am wrong, but it seems like the best time for full-scale strat-warm's is around mid-winter or so in order to "keep the party going."

Agreed though: Don't let that PV get too comfortable!

The idea is it could interfere with the base state if it occurs too early. Just because you  get a SSWE does not mean the outcome for cold and snow in our area is guaranteed. 

Many times a simple disruption and keeping the PV on our side of the pole is good enough. 

As @WxUSAF mentioned a SSWE later in the season is probably good for us. 

This year with a descending QBO  that should help us with blocking. I read that currently wave 2 activity is/will  taking punches to PV , but I believe we do not have significant wave 1 activity.  There are some precursor patterns that show up and you can look to these to place stress on the PV. 

Lastly, I read that the set up for this winter does not favor an official SSWE happening.  In that context I am happy with the way things are proceeding without a SSWE messing things up. 

I know Isotherm is releasing his winter outlook soon,  I respect his work and I am sure he will focus on the strat and the NAO domain. 

 

  

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4 minutes ago, frd said:

The idea is it could interfere with the base state if it occurs too early. Just because you  get a SSWE does not mean the outcome for cold and snow in our area is guaranteed. 

Many times a simple disruption and keeping the PV on our side of the pole is good enough. 

As @WxUSAF mentioned a SSWE later in the season is probably good for us. 

This year with a descending QBO  that should help us with blocking. I read that currently wave 2 activity is/will  taking punches to PV , but I believe we do not have significant wave 1 activity.  There are some precursor patterns that show up and you can look to these to place stress on the PV. 

Lastly, I read that the set up for this winter does not favor an official SSWE happening.  In that context I am happy with the way things are proceeding without a SSWE messing things up. 

I know Isotherm is releasing his winter outlook soon,  I respect his work and I am sure he will focus on the strat and the NAO domain. 

 

  

I don't mean to carpetbag my way in here and hijack your thread, but can you explain for me what's meant by "Wave 1" and "Wave 2?"  I think I have a decent idea of what they mean, but I can probably use a primer.

 

Great stuff in this thread!!  :-)

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15 minutes ago, Eduardo said:

I don't mean to carpetbag my way in here and hijack your thread, but can you explain for me what's meant by "Wave 1" and "Wave 2?"  I think I have a decent idea of what they mean, but I can probably use a primer.

 

Great stuff in this thread!!  :-)

 

A bit limited in time, however, I recommend this article, as it talks about various pieces of the puzzle. 

Here is a small section of the article . ( The article has decent images as well ) 

The stratospheric polar vortex shows quite a bit of day-to-day variability. This variability is caused by weather systems or large-scale waves that move upward from the troposphere into the stratosphere. In the left image (9 January 2010), we see some undulations along the edge of the polar vortex, but the vortex is generally centered on the North Pole. Two weeks later (center image on 23 January 2010) we see the center of the polar vortex pushed away from the North Pole. On a constant latitude circle, PV values are high in the eastern hemisphere and low in the western hemisphere. This is referred to as a wave-1 pattern (a wave-2 pattern can be seen in the vortex breakup section below). The wave-1 pattern develops in the troposphere and moves upward (propagates) into the stratosphere.

These stratospheric waves are forced by the large-scale mountain systems and the land-sea contrasts between the continents and oceans. During the northern winter, these waves are continuously forming and moving upward into the stratosphere. The waves can “break”, much like the waves on a beach. These wave-breaking events erode the vortex and keep the polar region warmer and ozone amounts higher. Often, parts of the polar vortex are pulled away from the main vortex. The image on the right (28 January 2010) shows this, where a large piece of the polar vortex was pulled away from the main vortex (green colored material at the bottom of the image). A comparison between the middle and right images also shows a slight contraction of the polar vortex because of these waves.

  link 

https://ozonewatch.gsfc.nasa.gov/facts/vortex_NH.html

 

 

 

And here is another good read

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/polar-vortex

sample section from above link

Wave-2/vortex splitting type

The most dramatic major warmings involve a complete split in the polar vortex, followed by a rapid breakdown of one or both of the two cyclonic vortices that result from this split. The growth of the Aleutian High is accompanied by the development of a second anticyclone in the vicinity of the Greenwich Meridian at 0° E. An unusually symmetrical example of a ‘wave-2’ major warming occurred in northern winter 1984/85. Its evolution is illustrated in Figure 7. There are two developing anticyclones: the Aleutian High near 180° E and another (nonclimatological) anticyclone near 0° E. The polar vortex was split in the ‘pincer’ formed by these anticyclones, which then merged over the pole, as shown in Figure 8, bringing warm air over the polar cap. Subsequently, both of the cyclones weakened rapidly as they were stretched out around the strong anticyclone over the pole. Often, vortex splitting events are preceded by a ‘preconditioning’ of the vortex in which it is displaced from the pole and elongated. This preconditioning has a strong signature in the wave number one geopotential height field meaning that separating vortex displacement and vortex splitting events purely on the basis of the amplitudes of the wave number one and two geopotential height field can be difficult. Instead, alternative methods, which focus on examining the two- and three-dimensional structure of the potential vorticity fields have proved a useful complement to traditional methods in classifying and understanding SSWs in recent years.

3-s2.0-B9780123822253002309-f00230-07-97

 

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Wave 1/2 just refers to wave number 1/2. So a wavenumber one means that there is one wave crest and one valley as you go around a latitude circle. Wavenumber 1 typically has more amplitude in the troposphere and stratosphere. Wavenumber 1 forcing typically displaces the strat vortex off the pole, while wavenumber 2 deforms and can split the vortex. A combination of both is typically needed for a total vortex disruption.

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@poolz1

 

This is a cool post I brought over from @Typhoon Tip in the NE Forum 

Someone asked about whether there would be a warming event by the end of November , here is what Tip wrote.  To me the image and the time issue involved is very interesting. And, as Tip mentioned,  in this upcoming winter we may not even need a warming to get a - AO. Sounds good to me .   

Here is the post 

 

<<<<

If there is one, keep in mind that there is a coherent time-lag in the statistical correlation.  Any subsequent forcing on the Arctic Oscillation lags by as much as 20 to 30 days. 

Few know this, or, demonstrate very readily via turns of phrase and deliveries of prose where they've beautifully ( otherwise ) fused the sudden stratospheric warming sciences into their speculative, and I'm like " ...you do realize the effects of SSW are outside your forecast range, right?." 

There is a particularity that needs to be observed, else ... whatever is being observed is more likely to fail coherent forcing on the AO outside of coincident index numerology. 

The warm plume has to propagate downward in time ( i.e., 'downwelling' ).  In every case of SSW graphical layout back to 1979, this downward motion appears to 'spiral' away from a central axial point that begins near the axis of PV rotation, at a very high beginning SIGMA level - typically between 5 and 30 hPa.  As it descends, it will first appear to weaken, before the next node comes in warmer, then fades slightly ... then warmer, each node gaining x-coordinate distance upon each emergence.  That growth in the x-coordinate is a representation of gaining distance from the axis of rotation.  

image.png.64992aaf71546882463503fe2e3f4eb0.png

Notice the ending node is almost faded/indistinquishable in anomaly relative to the surrounding features of the ambient field ( nearing 150 hPa SIGMA) there bottom right along the nodal curve.   That is tropopausal mechanical absorption/ increasing stabilization and suppression of the depths ensues, and that weakens the PV ... "pancaking" and blocking in the mid and upper troposphere ignites.  This entire translation of events, as you can see took ~ from Jan 15th to the end of February ... and we can see in this case a very clear and coherent AO correlation taking place:   

2013 -0.610 -1.007 -3.185  0.322  0.494  0.549 -0.011  0.154 -0.461  0.263  2.029  1.475    ... Bold is March. 

SSW don't really value-add like the popular mantra of the day has it in their mind(s) and bandy about.  If one did take place in the last week of this month... We may be hearing about an AO response some time after Christmas.. which is fine.  But, I also offer that this particular year we may not have much trouble with AO being negative anyway, so it could be lost in the din of a -AO complexion hemisphere anyway.   

>>>>>>>

 

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2 minutes ago, WxUSAF said:

Yeah it’s had it for 2 runs. Gfs for a few now also. 

Icon well positioned for the same just after the run ends. Would be surprised to still see this as a possibility after a couple more runs, though - I don't think our climo is as favorable as it was in 1987...!

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1 minute ago, yoda said:

Just me, or does Day 10 (as usual on the Euro lol) have potential?

I’ve seen worse, but looks like stale cold air which won’t work in November (barely works in January). What’s nice about the Monday/Tuesday threat is a very fresh and cold airmass.

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Here is that time period John was mentioning in his post earlier today. 

I would say you have to consider this as a potential snow event window as well, even though it is way out there. 

Of course this potential event may favor regions North of us, but plenty of time to work that out. One thing of note,  the continuous anomalous cold air from NW Canada feeding down the next 10 to 14 days.  

On a side note, I have heard from several respected mets that this winter will feature a few robust clippers and even Manitoba Maulers. I would love an exploding clipper to bomb out off the Va Capes and then doing a loop off Ocean City, MD  for say 24 hours. ;)

As John stated : Another threat for winter weather could evolve in the Northeast states from 11/11 - 11/13. As the closed ridge near the Chukchi Sea collapses, increased momentum/amplification could occur. The evolving waveguide could support a storm threat a few days later."

 

  ecmwf_z500_mslp_us_11.png

 

 

 

 

 

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I agree that the 11/12-13 threat has much more potential. The late week storm threat seems more like a frontal boundary that could bring some snow on the backend to interior New England and maybe parts of western NY and PA. Even some mood flakes are possible in the far northern and western suburbs depending on the track. This would shift the baroclinic zone farther southeast, which could end up working out in our favor if all goes right. You have a highly amplified west coast ridge, a deep trough, fresh injection of cold air, and some semblance of Greenland blocking starting this weekend. Actually a fairly similar setup to November 2014 and 2018.

We've seen D10 threats fall apart in the medium range, but this one is definitely worth monitoring. At the very least, a colder-than-normal November seems pretty likely at this point. 

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

This h5 look is something I would rather see as we are  approaching mid  Dec, but it's on the table so what the hell, maybe some part of our region can score something given the highly anomalous nature of the advertised pattern.

1573538400-XnBeM1TVIHo.png

That’s pure eye-candy if we’re in mid-December - the stuff of dreams.

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

This h5 look is something I would rather see as we are  approaching mid  Dec, but it's on the table so what the hell, maybe some part of our region can score something given the highly anomalous nature of the advertised pattern.

 

So,  then for me after looking at this  beautiful meteorological artwork is, what about the eventual flip,  and do we go back to a favorable pattern at some point ?

I think any relax is minimal,  but has to happen.  

The ensemble mean, as Maue points out,  is remarkable. 

Lets not forget in the process of all this cold is the building snow cover extent and depth to our North and Northwest.   I did read one thing from HM about N Pac ridging. However, I assume if that were a huge concern for December in the East Anthony would talk about it more.  

Here is the snippet from HM I was referring to:

<<

. Too much ridging in the N PAC and you end up with a 1990 situation--big +AO next month.

>>

 

 

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2 hours ago, frd said:

On a side note, I have heard from several respected mets that this winter will feature a few robust clippers and even Manitoba Maulers.

 

 

 

 

What is a Manitoba Mauler? I think i’ve heard the phrase before, but i cannot remember what it is...

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1 minute ago, Rhino16 said:

What is a Manitoba Mauler? I think i’ve heard the phrase before, but i cannot remember what it is...

An upper air feature, low pressure disturbance,  that move out of far W/NW Canada going SE ( quickly ) and passes over the province of Manitoba, Canada.

These features can at times drop far enough to our South and Southeast to spawn cyclogenesis. If they drop far enough to our South and the pattern is conducive they can develop into powerful East Coast snowstorms.  Sometimes these storms can even stall or loop as they move NE along the Eastern Seaboard dropping feet of snow.  

This diving system out of Canada shares common characteristics with Alberta clippers and even Saskatchewan Screamers. The name given simply implies the location they pass over.

Great link 

       https://www.9and10news.com/2011/01/03/alberta-clipper-saskatchewan-screamer-manitoba-mauler/

Canadian Provinces and Territories

 

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33 minutes ago, frd said:

So,  then for me after looking at this  beautiful meteorological artwork is, what about the eventual flip,  and do we go back to a favorable pattern at some point ?

I think any relax is minimal,  but has to happen.  

The ensemble mean, as Maue points out,  is remarkable. 

Lets not forget in the process of all this cold is the building snow cover extent and depth to our North and Northwest.   I did read one thing from HM about N Pac ridging. However, I assume if that were a huge concern for December in the East Anthony would talk about it more.  

Here is the snippet from HM I was referring to:

<<

. Too much ridging in the N PAC and you end up with a 1990 situation--big +AO next month.

>>

 

 

I was thinking that I hope thats not where the very long range looks are taking us (+AO).  Out there in lala land and is bound to change but I dont like losing the  +heights in AK and breaking that link with the ridging in Siberia.   You can see how fast that vortex retreats to pole and tries to hold hands with our Aleutian low.   

 On a glass half full note...maybe the scan ridge bullies the pattern anyway and we snap back to a -AO. 

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