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January 2019 Discussion

40/70 Benchmark

By 40/70 Benchmark,
in New England

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Typhoon Tip

Typhoon Tip

Posted
Posted
1 hour ago, qg_omega said:

SSW Vortex Split

 

Fwiw - the CPC AO recently updated this morning and indicates most members falling > 0 SD by the end of week 1 ... continuing to descend into week 2 ...  Not sure what that source is for that graphic, but it might be related to that bifurcating structure there...

ao.jpg.75731e8ce38f8d262eee22a36e794f6f.jpg

One aspect I'd like to bring to folks' attention ... a descending AO is good on paper ... not so much in practice if there are other factors interfering.  Namely ... should the general circulation structures over this side of the Hemisphere  align in favorable or unfavorable constructs for actually delivering cold over the N/A continent.  We've seen -AOs in the past ... concomitant blocking into middle latitudes happen to situate favorable for Eurasia ... When those took place, -45 F headlines out of Moscow are seen during 45 F mornings over here.  That happened in 2007 ... S of the 55th parallel over North America was basking in hatred with 59 F high temperatures in Tower Minnesota and fully thawed Earth from the lower Manitoba plains to northern Maine through December... The AO crashed in the first week of January, but it really took until almost the 20th of the month before the roulette wheel wound around and set up a pattern conducive to deliver cold here. It did ...and February saved that winter with a couple of decent events toward/for winter enthusiasts.

The point of this is, the AO is half of it...  we need to have the relay as well.  

Which is why one should be worried about the Pacific ...  I am still not abundantly certain whether that west-north-northeast Pacific are going to be entering a favorable AA, or unfavorable AB phase (the former correlates with -NP/-EPO). The primary cold loading pattern over N/A comes from variations of that ...  Typically, I would just rely upon the CDC 'public' products with their WPO and EPO but ... with the appropriations breakdown and the CDC being shut down for business... I don't know of any ancillary sources to find those indexes.  If the WPO is positive leading the MJO --> phase 7-8-1-2 ...the MJO's ability to modulate the pattern could remain in a destructive wave interference throughout that migration ...  and vice versa.  

I've noticed that the absurdly powerful GEFs MJO mean has been weakening in the last couple ...few days.  About five days ago, CPC really soared that curve (as we all know..) to the edge of the WH diagram space.  As of this morning, it looks more sensibly strong if not pedestrian in magnitude...as well, the end data points are picking up sites into phase 7.  The fact that curve is weakening prior to the wave actually progressing that far ... indicates that the Pacific "might" indeed already be less in sync/breaking down. 

The operational guidance versions haven't changed.  They don't look or even hint as of the overnight runs ... of really sniffing much of this out.  I'm not sure if the following comment has much operational merit but ... I wonder if this may materialize in a more coherent pattern change all at once ...quick fashion.  We'll be living our lives in silent frustration and than all of sudden we're looking at monitors and portable devices and it simply can't be true ... Then of course we have wade through all the defensive posturing by those who in reality only suppress their own giddiness.  

So the short version?  (... haha, made you read)... Despite the less than savory tenor of the operational runs, the GEFs -based teleconnectors flag changes for the winter enthusiasm.  Again, EPS notwithstanding...

 

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Typhoon Tip

Typhoon Tip

Posted
Posted
12 minutes ago, ORH_wxman said:

It's weird because even the ECMWF stratosphere diagnostics maps show the PV getting wrecked and split. I'd expect this is going to eventually show up on the tropospheric level more than it has so far. 

Yup... basically paraphrasing my New Year's morning gift to all - a popsycle headache :wacko:

It could simply be a matter of detection - In a sense the GEFs system "might" be adept at doing that, if perhaps more readily?  It's a question - not a statement of fact. ... But, given the philosophy behind the "Global Forecast System" - it may be a mere coincidence of naming convention but that 'sounds' like an attempt at a whole-scale integral.   The Euro is in fact (duh) a "Global" numerical model system too, just that obviously we cannot be certain what real scaffold of their model fields is from here.

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Ginx snewx

Ginx snewx

Posted
Posted
5 minutes ago, weathafella said:

EPS is worlds apart from GEFS and GEPS.  Let’s hioe for a North American win!

More and more convinced we are redoing winter 2013 like. Teleconnections are lining up. Delayed not denied. I just read Tips 2013 SSW discussion and all the discussion of winter cancel back then. Best was Kevins best friend and favorite Met Dave Epsteins cancelling of Winter 4 days before the biggest snow storm in CT since 78. Rays gonna nail this

https://www.boston.com/weather/weather/2013/02/02/cold_and_dry_to_start_weekend

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weathafella

weathafella

Posted
Posted
2 minutes ago, Hoth said:

Tough to go against the Euro, but didn't it have some pretty significant struggles this fall?

The fact that GEFS continues to trend the other way is a POSSIBLE sign to me that eps may not have the right idea but since it’s in the long range we probably won’t know for awhile.

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Hoth

Hoth

Posted
Posted
Just now, Ginx snewx said:

More and more convinced we are redoing winter 2013 like. Teleconnections are lining up. Delayed not denied. I just read Tips 2013 SSW discussion and all the discussion of winter cancel back then. Best was Kevins best friend and favorite Met Dave Epsteins cancelling of Winter 4 days before the biggest snow storm in CT since 78. Rays gonna nail this

https://www.boston.com/weather/weather/2013/02/02/cold_and_dry_to_start_weekend

Given my present location, I would be quite happy with an exact replay of Feb '13. 

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CoastalWx

CoastalWx

Posted
Posted
2 minutes ago, weathafella said:

The fact that GEFS continues to trend the other way is a POSSIBLE sign to me that eps may not have the right idea but since it’s in the long range we probably won’t know for awhile.

Sometimes when you have these bifurcations of solutions a compromise is in order. Even a 60/40 in favor of euro would be a big help. Let’s hope. 

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tombo82685

tombo82685

Posted
Posted
14 minutes ago, ORH_wxman said:

It's weird because even the ECMWF stratosphere diagnostics maps show the PV getting wrecked and split. I'd expect this is going to eventually show up on the tropospheric level more than it has so far. 

I can't see the NAM stuff for the euro, but the issue has been can the stratosphere couple with the troposphere. Some of the papers I have read is that you want -NAM in the 100-300mb zone to truly couple the troposphere with the stratosphere for impacts to start occurring. Looking at the latest plot (today hasn't updated) we continue to be in a +NAM index in that zone meaning the stratosphere isn't propagating down, atleast, yet. This could certainly change as we go out further as these impacts for the east usually take weeks to occur. You definitely want to keep an eye on this though. Not all SSW's have a response on the troposphere, think I saw 40% don't. They refer to them as nSSW's. Here is a good link to SSW's.

https://simonleewx.com/2018/12/27/not-all-ssws-were-created-equal/

geos_nh-namindex_20181231.png

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qg_omega

qg_omega

Posted
Posted
2 minutes ago, tombo82685 said:

I can't see the NAM stuff for the euro, but the issue has been can the stratosphere couple with the troposphere. Some of the papers I have read is that you want -NAM in the 100-300mb zone to truly couple the troposphere with the stratosphere for impacts to start occurring. Looking at the latest plot (today hasn't updated) we continue to be in a +NAM index in that zone meaning the stratosphere isn't propagating down, atleast, yet. This could certainly change as we go out further as these impacts for the east usually take weeks to occur. You definitely want to keep an eye on this though. Not all SSW's have a response on the troposphere, think I saw 40% don't. They refer to them as nSSW's. Here is a good link to SSW's.

https://simonleewx.com/2018/12/27/not-all-ssws-were-created-equal/

geos_nh-namindex_20181231.png

Best post of the year

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Typhoon Tip

Typhoon Tip

Posted
Posted
20 minutes ago, tombo82685 said:

I can't see the NAM stuff for the euro, but the issue has been can the stratosphere couple with the troposphere. Some of the papers I have read is that you want -NAM in the 100-300mb zone to truly couple the troposphere with the stratosphere for impacts to start occurring. Looking at the latest plot (today hasn't updated) we continue to be in a +NAM index in that zone meaning the stratosphere isn't propagating down, atleast, yet. This could certainly change as we go out further as these impacts for the east usually take weeks to occur. You definitely want to keep an eye on this though. Not all SSW's have a response on the troposphere, think I saw 40% don't. They refer to them as nSSW's. Here is a good link to SSW's.

https://simonleewx.com/2018/12/27/not-all-ssws-were-created-equal/

 

The downward propagation is/was a question no one was evading, and in fact ... some of us even hammered that requirement for the AO correlations to the point of cephalic pressure... 

Much of what is in discussion is predicated on that being the case  -

But just to be clear, the "NAM" IS the Arctic Oscillation ... and it doesn't lead the SSW/downwelling phenomenon ... In present context, it is a result - you seem to have it backward.

The "-NAM" is a scalar measurement, a RESULT of that coupling taking place...

So...fyi general reader: there is no predictive bases for saying that won't happen because it happens to be positive as we type.  

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Ginx snewx

Ginx snewx

Posted
Posted
Just now, Hoth said:

Timeframe wasn't clear from what I saw, but he mentions how the process of buckling the Pacific flow aids in Atlantic equatorward wave breaking and helps bring the NAO negative. 

Yes we discussed how qgomegas insistance that having a TPV over Europe is a bad thing when in fact this aids in slowing the flow and buckling it.

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Ginx snewx

Ginx snewx

Posted
Posted
38 minutes ago, Hoth said:

Given my present location, I would be quite happy with an exact replay of Feb '13. 

Lol Probably not happening but you understand the implications. Perhaps you have read before my discussion of the dam break in Canada. Canada is getting super cold coming up, as soon as the Pac Jet relaxes the dam will spring a leak, first will be leaks then the whole enchilada. Get us the cold it will snow. None of this faux winter where it snows 6 to 8 then warms up followed by a rain pattern, a real deal pattern development. 

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Typhoon Tip

Typhoon Tip

Posted
Posted
10 minutes ago, CoastalWx said:

Never mind the AO/NAO.....gotta get the PAC out of the +PUKE stage. I care more about that than any downwelling wave.

Yeah... it's certainly related ... you've just echoed some of my own sentiments above.

The AO could flip negative but ... if the Pacific is out of sync relative to ideal for us... then our vortex member post the split may be comparatively weak.... Eurasia goes syrup cold.

But ...just the same, it's not fixed ... It could start out that way...then break favorably during the total duration of block tendency..  Just sort of means we have to wait our turn.

If folks care to look .... there is a new warm intrusion showing up in the GEFs product in the 1 to 10 hPa sigma levels ... out around D9. Some of those GEFs members have been indicating more easterly anomalies persisting along and N of the 60th parallel in the PV - they may be onto something?  If so, it would likely indicate Wave 2 breaks and so forth with a migratory SPVs post any alignment of initial split features.  In other words, where ever the first nodal vortexes find a home may be transient.   

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CoastalWx

CoastalWx

Posted
Posted
1 minute ago, Typhoon Tip said:

Yeah... it's certainly related ... you've just echoed some of my own sentiments above.

The AO could flip negative but ... if the Pacific is out of sync relative to ideal for us... then our vortex member post the split may be comparatively weak.... Eurasia goes syrup cold.

But ...just the same, it's not fixed ... It could start out that way...then break favorably during the total duration of block tendency..  Just sort of means we have to wait our turn.

If folks care to look .... there is a new warm intrusion showing up in the GEFs product in the 1 to 10 hPa sigma levels ...  So, those GEFs members that indicate easterly anomalies persisting along and N of the 60th parallel in the PV may be onto something?  If so, it would likely indicate Wave 2 breaks and so forth with a migratory SPVs post any alignment of initial split features.  In other words, where ever the first nodal vortexes find a home may be transient.   

We still have strong warmth progged even in the 11-15 day at 50mb on the EPS. So thermal wind arguments alone say easterlies. 10mb starting to cool, but par for the course I think. Hopefully some of those products that show downwelling start to occur later this month.

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512high

512high

Posted
Posted
1 minute ago, CoastalWx said:

We still have strong warmth progged even in the 11-15 day at 50mb on the EPS. So thermal wind arguments alone say easterlies. 10mb starting to cool, but par for the course I think. Hopefully some of those products that show downwelling start to occur later this month.

Scott, with that said, can we sneak events in under those conditions ? or will they result in the same old we have been getting here in southern parts etc?

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