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Winter 2014-2015 Pattern Discussion Thread II

JoshM

By JoshM,
in Southeastern States

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SnowNiner

SnowNiner

Posted
Posted

Yep, doesn't get any more blunt than this....he saying 1-2 weeks before we see the effects, so you figure by Jan 15th AO should be negative until atleast end of Feb.  

 

Following a SSW a negative AO is favored for up to 60 days.

 

Yeah, but didn't you see all his caveats and footnotes?  He said it like 14 times throughout the report.  To me he's essentially stating that the anomalous low was the reason the SAI didn't work out so far and why the -AO might still not go negative.  Pluse are we sure there's actually going to be a true SSW?

 

  • Following a SSW a negative AO is favored for up to 60 days.  However anomalous low pressure across the Barents-Kara seas and northern Eurasia destructively interferes with externally forced negative AO conditions and introduces uncertainty longer term.
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Bevo

Bevo

Posted
Posted

 

Yeah, but didn't you see all his caveats and footnotes?  He said it like 14 times throughout the report.  To me he's essentially stating that the anomalous low was the reason the SAI didn't work out so far and why the -AO might still not go negative.  Pluse are we sure there's actually going to be a true SSW?

 

  • Following a SSW a negative AO is favored for up to 60 days.  However anomalous low pressure across the Barents-Kara seas and northern Eurasia destructively interferes with externally forced negative AO conditions and introduces uncertainty longer term.

 

 

I thought it was already underway. Did I make that up? I make stuff up sometimes. Just sayin'.

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GaWx

GaWx

Posted
Posted

I thought it was already underway. Did I make that up? I make stuff up sometimes. Just sayin'.

 

Strat. warming is definitely already underway. Cohen is referring to it peaking in early Jan. The question is whether or not it will be classified as a major SSW, which depends on the criteria used to measure that.

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deltadog03

deltadog03

Posted
Posted

More on the GFS on my FB page...BUT I actually think the GFS could be sniffing something out.  I know it doesn't really show anyting, storm wise, right now, but that energy in the DEEP SW could have spokes of energy flying out E and that could be enough to have some nice overrunning event.  Especially with cold highs coming down the pike.  

 

https://www.facebook.com/ChriswxmanSimmons

 

fxt99g.jpg

t5niuc.jpg

2vv5iix.jpg

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Webberweather53

Webberweather53

Posted
Posted

 

Yeah, but didn't you see all his caveats and footnotes?  He said it like 14 times throughout the report.  To me he's essentially stating that the anomalous low was the reason the SAI didn't work out so far and why the -AO might still not go negative.  Pluse are we sure there's actually going to be a true SSW?

 

  • Following a SSW a negative AO is favored for up to 60 days.  However anomalous low pressure across the Barents-Kara seas and northern Eurasia destructively interferes with externally forced negative AO conditions and introduces uncertainty longer term.

 

 

 

I think you're referencing a major stratospheric warming event where the zonal stratospheric winds turn easterly, and as GaWx mentioned, we already have a minor event well underway and a split of the vortex appears likely at this point, the exact intensity of the SSWE is uncertain of course...

 

December 29 ECMWF initialization 10mb heights & temperatures

 

ecmwf10a12.gif

 

 

 

More on the GFS on my FB page...BUT I actually think the GFS could be sniffing something out.  I know it doesn't really show anyting, storm wise, right now, but that energy in the DEEP SW could have spokes of energy flying out E and that could be enough to have some nice overrunning event.  Especially with cold highs coming down the pike.  

 

https://www.facebook.com/ChriswxmanSimmons

 

 

 

 

 

I agree, we have the synoptic pattern we want to get a storm in the southern tier, we just have to satisfy a host of other conditions of course to get there, but along w/ everything else that's in place, I (continue) to like what I'm seeing at this stage in the game for the 2nd week of January...

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packbacker

packbacker

Posted
Posted

 

Yeah, but didn't you see all his caveats and footnotes?  He said it like 14 times throughout the report.  To me he's essentially stating that the anomalous low was the reason the SAI didn't work out so far and why the -AO might still not go negative.  Pluse are we sure there's actually going to be a true SSW?

 

  • Following a SSW a negative AO is favored for up to 60 days.  However anomalous low pressure across the Barents-Kara seas and northern Eurasia destructively interferes with externally forced negative AO conditions and introduces uncertainty longer term.

 

 

He details that below with this...

 

Perhaps the current temporary relaxation is a foreshadowing of a longer term weakening trend but for as long as the Barents-Kara seas low persists, it destructively interferes with an externally forced negative AO (from the SSW).  The biggest impact would to inhibit the flow of Siberian air into Europe.  It’s impact would be less on North American temperatures where in the near term, ridging across western North America and a polar low in eastern Canada will direct arctic air into the lower 48.

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Cold Rain

Cold Rain

Posted
Posted

  • The strong wave driving will result in a sudden stratospheric warming (SSW) and a splitting of the polar vortex. In the near term this will help build ridging across Western North America and cold temperatures across the United States after the New Year.

 

  • Following a SSW a negative AO is favored for up to 60 days. However anomalous low pressure across the Barents-Kara seas and northern Eurasia destructively interferes with externally forced negative AO conditions and introduces uncertainty longer term.

HERE'S MORE:

However longer-term prospects for the AO continue to hinge on the anomalous polar low in the Barents Kara-seas region that has temporarily weakened. It is predicted to strengthen again across the north slope of Siberia and eventually move back over the Barents Kara seas region. Perhaps the current temporary relaxation is a foreshadowing of a longer term weakening trend but for as long as the Barents-Kara seas low persists, it destructively interferes with an externally forced negative AO (from the SSW). The biggest impact would to inhibit the flow of Siberian air into Europe. It’s impact would be less on North American temperatures where in the near term, ridging across western North America and a polar low in eastern Canada will direct arctic air into the lower 48.

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Webberweather53

Webberweather53

Posted
Posted

I should mention thanks in part to Chris Simmons asking Ryan Maue for Parallel GFS scores, that the old GFS is still beating the parallel (PRX) GFS in the medium range (hr 120) in terms of 500mb heights & temperatures

 

 

 

 

cor_day5_HGT_P500_G2NHX.png

cor_day5_T_P850_G2NHX.png

 

The Eulerian GFS being run by the Indian National Center for Medium Range Weather Forecasting (NCMRWF) is actually out-performing the ECMWF w/ respect to the day 10 northern hemisphere 500mb, all of the energy ejecting out of the southwestern US is likely giving the Euro & even its ensembles a few headaches... Parallel GFS also has a slight lead over the regular GFS at this range (in fact, once you get beyond day 6, the parallel GFS is better than the operational generally across the board & it's second, only to the ECMWF) Not too surprisingly, the CFS is at the bottom of the barrel, even the Canadian is better... Lol

cor_day10_HGT_P500_G2NHX.png

 

Here is the link to the website so you can see the data for yourself...

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/

 

In short, the ECMWF is still winning, the operational GFS is generally better in the medium-short range, but as you get later into the model run, the parallel GFS picks up the slack...

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burgertime

burgertime

Posted
Posted

I should mention thanks in part to Chris Simmons asking Ryan Maue for Parallel GFS scores, that the old GFS is still beating the parallel (PRX) GFS in the medium range (hr 120) in terms of 500mb heights & temperatures

 

 

The Eulerian GFS being run by the Indian National Center for Medium Range Weather Forecasting (NCMRWF) is actually out-performing the ECMWF w/ respect to the day 10 northern hemisphere 500mb, all of the energy ejecting out of the southwestern US is likely giving the Euro & even its ensembles a few headaches... Parallel GFS also has a slight lead over the regular GFS at this range (in fact, once you get beyond day 6, the parallel GFS is better than the operational generally across the board & it's second, only to the ECMWF) Not too surprisingly, the CFS is at the bottom of the barrel, even the Canadian is better... Lol

 

 

Here is the link to the website so you can see the data for yourself...

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/

 

In short, the ECMWF is still winning, the operational GFS is generally better in the medium-short range, but as you get later into the model run, the parallel GFS picks up the slack...

 

Interesting. Thanks for sharing. 

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burgertime

burgertime

Posted
Posted

Can't be as extreme as the para. Ridge out west taking a beating and the risge/trough axis is too far east for any storms. It will get temps below normal for a few days.

SE ridge beat down!

 

Yea and probably the PARA is too extreme more than likely. We would probably end up with something in the middle. Should be interesting to see if the Euro ENS is better with the ridge and PV. 

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Jon

Jon

Posted
Posted

So now the mets are all over the place like the models. :)

Yep just like the posters on this forum. We all have differing opinions, and biases, mets are not excused from this! Fun times ahead. Brad P has been around in this region a long time, I trust his opinion, then again we share the same opinion.
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Smoked

Smoked

Posted
Posted

To some extent we are only as good as the data available to us ;)

 

I agree with some others that the large scale pattern seems to be moving in the right direction. However it is difficult to nail down specific storm opportunities beyond 5-7 days especially since models have had difficulty recently with the medium and long range. However, we greatly improve our chances for the long range with cold air building in Canada and a trough axis seeming to want to set up somewhere across the middle to eastern US. Just have to play the waiting game until the pattern takes shape.

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