October/November 2019 Mid/Long Range

[showmethesnow]

Euro/EPS is still biting on this period of time that it hinted at last week at the end of its extended with a Coastal/Miller B solution on its overnight run. What we are seeing is a weak impulse of PAC jet energy sliding to our south through VA. 500's dropping in behind it initiate coastal development of this energy. 

 

 

500's are closing off and dropping down through southern MD/N VA. We are seeing such a robust 500 solution due to interaction between NS energy and PV energy as they drop in through the Mid-west. 

 

Below we can see the different pieces of energy that are involved. We have the NS (north stream) energy that has ridden up and over the EPO ridge and is now dropping down into the Midwest. Beside it we see the energy that is rotating around the PV and dropping in behind the NS energy in a favorable position for phasing. Underneath these features we see the PAC energy which will slide to the south then turn up through VA and then the coast. The combined NS/PV energy is dropping down behind the PAC energy, again in a favorable position, but the timing between these two features is slightly off. Thus we are seeing a phase up off the NE coast, far too late to benefit us. This results in a modest coastal for our region but nothing I would call explosive. But... speed up the NS/PV energy or slow down the PAC energy to decrease the distance/timing between the two and we probably have explosive development, which would probably occur farther south in a much more favorable local for the metros. Now we are talking features (energy in the midlevels) that the models will have difficulty handling at 7/8 days . Timing will always be suspect as well as the fact that these packets of energy may only be a figment of the models imagination (I start taking the models somewhat seriously with these features when we get within 3 days or so).

 

Below we have the 10-1 snowfall map. Looks as if @C.A.P.E. will be taking a trip to Bethany/Rehoboth again. Maybe @WxWatcher007 will split the costs of a room with him. All I can say to them is, post pics.  

 

ETA: Actually some pretty good support from the EPS for development of a low in the east and/or off the coast during this time.

 

 

 

[showmethesnow]

06Z GFS took a decent step towards the Euro for the day 7/8 system.

[CAPE]

@showmethesnow

Nice write up. This period has been popping out as one with some potential. The usual caveats- its early, climo, etc. It would take a pretty anomalous airmass/set up for it to snow on the coast the second week of November, but it can happen, and the h5 looks we are seeing from the guidance lately is pretty anomalous looking lol.

[CAPE]

Just now, showmethesnow said:

06Z GFS took a decent step towards the Euro for the day 7/8 system.

It needs to get steppin' to catch up to pretty much all other guidance, including the ICON. Or maybe it will score a coup with the suppressed event.

[showmethesnow]

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

It needs to get steppin' to catch up to pretty much all other guidance, including the ICON. Or maybe it will score a coup with the suppressed event.

I can't help but remember the olden days when the GFS came in suppressed in this time frame that we knew we were golden. Through the different versions we have seen since we have still seen the tendency to suppress but nowhere near to the degree we were seeing 10 years ago.  As far as the newest version? Still trying to get a feel. Sometimes I think it shows this tendency and other times not so much. 

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

@showmethesnow

Nice write up. This period has been popping out as one with some potential. The usual caveats- its early, climo, etc. It would take a pretty anomalous airmass/set up for it to snow on the coast the second week of November, but it can happen, and the h5 looks we are seeing from the guidance lately is pretty anomalous looking lol.

Last week when this period first started to broach the extended I felt it had some decent potential. Just the general overall look/wavelengths showed promise. Nice to see that it has held and we are now within 7/8 days. But as you said Nov temps/climo can be a killer, especially for the metros. But the latest Euro solution is so close (bombing low off our coast) that I highly doubt temps would be an issue in such a scenario. All that said, Isn't it about time the Euro starts thinking about dashing our hopes small step by small step? And the GFS starts giving us false hope?

[frd]

The MJO has gotten my interest as of late . Also of note,  the lack of the MJO going into very high amplitude. 

Also, seeing the signs of more favorable phases for us here.

There is a lot more to the MJO as well as certain phases aid in  strat disruptions. 

I see today the SOI making a big move  down as well   

4 Nov 2019

1008.28

1010.80

-34.36

-4.51

-7.07

 

Keep this in mind as well 

 

 

 

 

[frd]

Continued trends downward with the AO and trending up with the PNA

 

 

[frd]

Pretty crazy look forecasted around mid November and the implications for the strat.

 

[WxUSAF]

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

[Eduardo]

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!

[WxUSAF]

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. 

[frd]

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. 

 

  

[Eduardo]

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!!  :-)

[frd]

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.

 

[WxUSAF]

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.

[frd]

@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.  

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.   

>>>>>>>

 

[psuhoffman]

2 hours 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.

Hopefully this year talk about the Strat gets neglected because we are too busy analyzing  medium to short range threats. 

[WxUSAF]

Gfs with a nice little snow event next Monday. Hoffman even gets fringed. Nothing like cold powder in mid November. 

[mappy]

5 minutes ago, WxUSAF said:

Gfs with a nice little snow event next Monday. Hoffman even gets fringed. Nothing like cold powder in mid November. 

Euro had it too. 

[yoda]

8 minutes ago, WxUSAF said:

Gfs with a nice little snow event next Monday. Hoffman even gets fringed. Nothing like cold powder in mid November. 

Wes jackpots on the 12z GFS

 

[WxUSAF]

4 minutes ago, mappy said:

Euro had it too. 

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

[yoda]

FWIW, 12z ICON at the very end of its run has some snow falling in SW VA/S WV area moving NE... 1-2" down there at the very end of its run... so possibly on board with GFS and EURO

[eurojosh]

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...!

[yoda]

12z CMC has snowfall for the northern third of the LWX CWA... but its a late Tuesday into Wednesday "event" next week instead of the Monday/Tuesday the other models are showing

[frd]

Cool animation John created here.  Certainly seems there is potential in this time period. 

 

 

 

 

[yoda]

Might be a stupid question... but does the end of the week system up in SNE affect our chance of snow down here at the beginning of next week?  Case in point the 12z Euro crushes parts of the NE... would that make the threat for us less or more?  Or is there no affect at all?

[WxUSAF]

Euro weaker and slower for the early next week event. Verbatim clips the eastern shore and Cape Cod. Still has the event either way. 

Damn cold period coming up. 

[yoda]

30 minutes ago, WxUSAF said:

Euro weaker and slower for the early next week event. Verbatim clips the eastern shore and Cape Cod. Still has the event either way. 

Damn cold period coming up. 

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

[WxUSAF]

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.

[frd]

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."