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December Medium/Long Range Discussion

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45 minutes ago, Ralph Wiggum said:

I dont consider myself knowledgeable on the 10hPa PV. In layman's terms, what does this weakening SPV translate to down in the trop? These SSWE's are discussed ad nauseum every year anymore it seems, but why? I know we can't say what it means for particular regions, but is it safe to assume with SPV weakening the PV doesn't allow it to 'stack vertically' over the Arctic Circle and can thus cause more displacing of the TPV and lobes to freely roam and wobble around rather than just remain anchored and stationary well to the N? Thanks.

There are some good scholarly papers on the TPV/SPV relationship(and correlation to the AO), and its complex to say the least. They are completely separate entities, and sometimes there is little to no interaction(coupling) during winter. The reality is, for sensible weather, we are far more interested in the TPV, which is actually larger(multiple vortices), and directly influences our weather. We want a pattern that can disrupt and dislodge these vortices, and bring them south. That's how we get the cold down into the midlatitudes. It can happen at times even with a relatively strong SPV/+AO, as occurred 2013-14 with the big EPO/WPO block. In general though, when we have a persistently negative AO winter(which we clearly want) the SPV is a weakling, and it gets that way largely by transfer of heat into the upper trop/strat.

eta- @Ralph Wiggum

Good read here: https://journals.ametsoc.org/view/journals/bams/98/1/bams-d-15-00212.1.xml

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1 hour ago, CAPE said:

Latest GEFS for early Jan. This isn't a good look if you are a polar vortex.

1609740000-Wf2bUcjuT5M.png

Don’t do that man. All I saw was this isn’t a good look LOL 

  • Haha 9

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1 minute ago, jaydreb said:

GFS trending the wrong way for xmas snow.  Also gives us a nice rainy coastal a few days later.  

I’ve see this before I think...lol

 

that would be extra painful but good thing it’s an eternity away

33FE0EF7-23D9-4D73-86DD-D9B91F5721EA.png

  • Haha 1

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1 hour ago, losetoa6 said:

 Mothman? ....or boobs ?

Def boobs

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28 minutes ago, LP08 said:

I’ve see this before I think...lol

 

that would be extra painful but good thing it’s an eternity away

33FE0EF7-23D9-4D73-86DD-D9B91F5721EA.png

OP  at range, but it's almost the exact same location as the last of debacle.

Really looking to achieve offshore ideal track, hopefully upstream blocking will shake things up. 

Also this regarding the 25th. 

Model guidance will continue to struggle with the #Christmas
 
Christmas_2020.png
system. The storm energy is currently located over a data sparse region of the north pacific & is embedded within a broad/complex jet streak. The energy is incident on the west coast by Monday evening.
 
 
Image
 
Image
 

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GFS ops have insisted on the monster block developing after the x-mas frontal passage.....and reloads it this run.  Ens up to now seem pretty muted....you would think there would be a better signal.  Wait and see...

eta:  12z gefs sniffing it out now....

bDJmIZi.png

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21 minutes ago, poolz1 said:

GFS ops have insisted on the monster block developing after the x-mas frontal passage.....and reloads it this run.  Ens up to now seem pretty muted....you would think there would be a better signal.  Wait and see...

eta:  12z gefs sniffing it out now....

bDJmIZi.png

If that verifies I know the Op gfs shows that low inland, but we’d def be able to pinch that H5 low farther southeast. Long way to go. Could be a mirage, could be a signal....

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25 minutes ago, poolz1 said:

GFS ops have insisted on the monster block developing after the x-mas frontal passage.....and reloads it this run.  Ens up to now seem pretty muted....you would think there would be a better signal.  Wait and see...

Also pondering data sparse regions with some of these Northern disturbances and last minute model swings. 

HM did mention if blocking develops robustly as the models indicate it could lead  to interesting low latitude winter storm analogs. 

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@poolz1 was just coming to say that GEFS definitely has some support for a storm running to our south with a cold high to the north around D9. Not much more to say at this point. ~D12 or so also. 
 

Pattern looks active AF from Xmas onward with a stout -NAO and -AO. Rest up now..

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1 minute ago, WxUSAF said:

@poolz1 was just coming to say that GEFS definitely has some support for a storm running to our south with a cold high to the north around D9. Not much more to say at this point. ~D12 or so also. 
 

Pattern looks active AF from Xmas onward with a stout -NAO and -AO. Rest up now..

Really does look active!  Right as start entering prime climo too....

The fact that we had nothing last year and it being the first threat of the season....I am still recuperating from the last track..lol  

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1 hour ago, frd said:

OP  at range, but it's almost the exact same location as the last of debacle.

Really looking to achieve offshore ideal track, hopefully upstream blocking will shake things up. 

Also this regarding the 25th. 

Model guidance will continue to struggle with the #Christmas
 
Christmas_2020.png
system. The storm energy is currently located over a data sparse region of the north pacific & is embedded within a broad/complex jet streak. The energy is incident on the west coast by Monday evening.
 
 
Image
 
Image
 

Thanks for the data, good info

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Good to see the latest GEFS runs building the NA ridging further NW closer to the classic position in the LR. I figured we would see that adjustment, with so many recent op runs depicting a perfectly placed monster of a west based -NAO. EPS still has the +heights focused a bit too far east but seems to be incrementally improving as well.

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1 hour ago, LP08 said:

I’ve see this before I think...lol

 

that would be extra painful but good thing it’s an eternity away

33FE0EF7-23D9-4D73-86DD-D9B91F5721EA.png

Stop hugging the surface maps. H5 argues strongly against this, especially the ens mean.

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6 minutes ago, Ralph Wiggum said:

Stop hugging the surface maps. H5 argues strongly against this, especially the ens mean.

Lol yikes.  Trust me I’m not.  I thought it was funny since it was basically identical.

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