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Winter 2014-2015 Pattern Discussion Thread III


BIG FROSTY

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All the models suck! My account is at -4,345.09, with all the " money" looks on the models this year! Don't know why we can't stop looking, but after next weeks cold rain or two, the GFS long range , looks like a dumpster fire, fwiw!

I think the CFS has consistently shown dumpster fire conditions for basically the entire winter up to this point, though.

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I'm fine if it stays dead honestly. I don't think it's helped us very much this winter, right?

 

Well, the most significant/widespread wintry weather event thus far this winter across central NC back on January 13-14 occurred of course when the MJO was in phase 7...

last.90d.noENSO.RMMPhase.png

accum.freezing.20150113.png

 

and the most recent event w/ snow from the powerful storm system southeast of New England that clipped areas of northeastern NC (which was a classic Miller B set-up (although a bit too far to the north to give central NC much, if any wintry precip), w/ one region of low pressure decaying west of the Appalachians over the eastern OH/TN valleys and a new low forming near the coast of NC...) 

 

The pattern response to the MJO in general has generally been what one would expect, w/ a stronger, more extensive Pacific Jet when the convectively active phase of the MJO migrated into the Pacific, and then significant anticyclonic wave breaking events over Alaska and the far north Pacific when the MJO started to encroach on the Maritime Continent (i.e. -EPO/WPO surges). This makes sense given that the mean response to the MJO's active cell & vigorous latent heating in boreal winter is for vigorous mid-upper level ridging to northeast of the enhanced convective signal, as the upper level divergence directly to the north of the upward MJO phase hastens the mid-latitude jet, promotes anomalous jet streaks, & allows for mid-latitude Rossby Wave propagation directly into the tropics through westerly wind ducts located over the eastern Pacific, an upper level trough usually forms in the vicinity of Hawaii. Thus, further amplifying the MJO's inactive phase over the central pacific w/ anomalous convergence on the western side of the trough, while also acting like a rock in the mean stream flow. This Hawaiian trough hence, commences the amplification of the southern branch of the jet, causing the planetary waves to break anticyclonically to the north & northeast, which in essence creates a +TNH, -EPO/WPO, & Pacific-based Rex Blocking.

The last 2 MJO events in the Western Indian Ocean/Maritime Continent have led to precisely this sort of pattern, however, it does appear this pattern response to the E hem MJO stimulus is shifted about 20-30N from its "climatological" juxtapositioning...

 

Nov-20-December-4-N-hem-500mb-E-hem-MJO.

N-hem-500mb-Eastern-Hemisphere-MJO-Dec-1

TNH-EPO-WPO-DJF-N-hem-500mb-1024x420.jpg

MJO Phase 3, 4, & 5 DJF N hem 500mb (w/ amplitude >1)

DJF-Phase-3-MJO-N-Hem-500mb-amplitude-10

DJF-MJO-Phase-4-N-hem-500mb-amplitude-10

DJF-MJO-Phase-5-N-hem-500mb-amplitude-10

Additionally, it also appears evident in those composites that the +PDO w/ the ring of warmer than normal water off the US west coast is giving this pattern a boost... (I should mention that the warmer than normal water on the west coast likely originated from multiple sources... not only via the persistence of last year's warm pool in the Gulf of Alaska, but also the massive downwelling Oceanic Kelvin Wave last spring. Once this oceanic KW deflected against the eastern boundary region of the Pacific (i.e. South America), it re-distributed some of the already displaced warm water out of the Indo-West Pacific Warm pool region in the equatorial Pacific poleward along the west coast of the Americas as coastally trapped oceanic kelvin waves (these coastally trapped Kelvin Waves also likely interfered w/ the cold California current) eventually creating a large glob of warm water against the west coast of N America. 

 

You can even see in this animation how some of the leftover warm water from the downwelling KW has started to disperse & migrate towards the north after hitting the coast of Ecuador, southern Columbia, & northern Peru...

https://bobtisdale.files.wordpress.com/2014/06/anima-1-ssh-v-h300.gif

anima-1-ssh-v-h300.gif

As the mid-latitude jet began to mature, this warm water forced prominent ridging along the US West Coast & Alaska, in essence, coercing a trough upstream in the vicinity of the Aleutian islands to intensify, and the end result was the creation of anomalously cold tongue of water within the KOE (Kurioshio-Oyashio Extension) and a +PDO.

 

Essentially, the MJO has been actually quite beneficial to our winter thus far & the most prominent MJO relationship to snow here in NC (January MJO phase 7) verified. The strong +PDO base state created by persistence of warm water in the GOA from last winter & last spring's large downwelling oceanic KW, has forced the entire Pacific extratropical pattern signature during Eastern hemisphere MJO events to shift northward from its usual positioning, enticing the genesis of a large Alaskan Ridge as opposed its placement much further south over the Gulf of Alaska

 

BTW, CCKW progression through the western hemisphere & forecasts for -200VP in 30-60E band just after Feb 5th is starting to reel me into this upcoming threat around February 5-6th...

vp200.GFS.anom.KELVIN.5S-5N.png

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Looking at the last 4 weeks or so of winter, the nightmare is almost over.  The GEFS and EPS are showing a return to above normal temps in the 5-10 day period.  Both show hints of a colder/stormier pattern in the 11+ day but I have my doubts it returns that quickly.  I would imagine after the 20th or so things may go back to a +PNA pattern, but a whole lot of good that's done us this winter.  The GEFS does actually show the best looking pattern in the 11+ day but it's done that a few times this winter and obviously it was wrong....

 

I feel very confident, atleast for RDU, our non-measurable snow streak will continue until next winter.

 

Edit:  Looks like great skiing weather in CO.

post-2311-0-97811200-1422883917_thumb.pn

post-2311-0-56941900-1422883925_thumb.pn

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Hey Pack, I don't think a trace is non measurable. It's actually measured as a trace. JK!!

The Shutout* continues....

 

Yesterday I actually went looking for a new snow measuring stick, since Feb is our best month and all, but none of them had a "T" for measuring traces of snow, peculiar.  

 

Just had a chance to look at the 6z GFS; and you would think somewhere in the next couple of weeks we could at least score a minor event. It does show some fantasy snows and at this point that's all it is, but eventually something has to really pop.  

 

Let's hope we don't score a minor event, then all we are going to here about how this winter isn't bad, Feb is our best month, blah blah blah, all over a sloppy 1-2".  

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I have a general question about the teleconnection graphs done by the models. Do they tend to be really accurate in the D10+ range? Or do they change and flip-flop just like the geographical models?

 

The teleconnection graphs are based on the same model output.  The ones that Cold Rain posts are updated once a day based on the 00z GFS Ensembles.  Each red line in the graph represents a single ensemble member.  Accuracy degrades as you go out in time.

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Additionally, it also appears evident in those composites that the +PDO w/ the ring of warmer than normal water off the US west coast is giving this pattern a boost... (I should mention that the warmer than normal water on the west coast likely originated from multiple sources... not only via the persistence of last year's warm pool in the Gulf of Alaska, but also the massive downwelling Oceanic Kelvin Wave last spring. Once this oceanic KW deflected against the eastern boundary region of the Pacific (i.e. South America), it re-distributed some of the already displaced warm water out of the Indo-West Pacific Warm pool region in the equatorial Pacific poleward along the west coast of the Americas as coastally trapped oceanic kelvin waves (these coastally trapped Kelvin Waves also likely interfered w/ the cold California current) eventually creating a large glob of warm water against the west coast of N America. 

 

You can even see in this animation how some of the leftover warm water from the downwelling KW has started to disperse & migrate towards the north after hitting the coast of Ecuador, southern Columbia, & northern Peru...

https://bobtisdale.files.wordpress.com/2014/06/anima-1-ssh-v-h300.gif

As the mid-latitude jet began to mature, this warm water forced prominent ridging along the US West Coast & Alaska, in essence, coercing a trough upstream in the vicinity of the Aleutian islands to intensify, and the end result was the creation of anomalously cold tongue of water within the KOE (Kurioshio-Oyashio Extension) and a +PDO.

 

Great post here.

 

I think the number one question I have is how long will this +PDO shift last. Have we entered a new multidecadal positive phase or is this just a strong positive spike in the current -PDO regime that either started in the late 90s or the mid 2000s? Obviously this has implications severe weather wise for me since a +PDO tends to favour a +PNA, which in turn tends to suppress severe weather activity.

 

Also brought this up elsewhere, but the QBO data for January is in and it came in at -26.70, record strong -QBO for January in the ESRL dataset.

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It's looking like teleconnections are for the first time going to be on our side this winter. GFS and GEFS all have a strongly negative AO/NAO and keep the PNA positive.  The problem is it doesn't seem like the EPS is on board with that. Gotta dream the GFS is correct. 

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Yes, pretty nice; some of those systems, especially on the overnight run of the GFS would cripple West and Middle TN; I like snow but not sure that I want 15"; I think the pattern is changing in our favor I will be surprised if we dont get at least a couple of good systems. The good thing about the South is that it takes just one good hit to make it a memorable year.

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2/13 to 2/18 does look good on there. Of course we are 10 days out again for the first threat. We know how that has gone so far this winter. 

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The indices don't look bad in the LR but indicate that the same overall (averaged) winter setup will continue:

 

PNA - Does look to go solidly positive; maybe even +1

NAO - Looks to stay positive; but would only be slight positive.

AO - Looks to jump to positive then in the LR I have no idea. Individual runs are all over the place.

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/teleconnections.shtml

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The indices don't look bad in the LR but indicate that the same overall (averaged) winter setup will continue:

PNA - Does look to go solidly positive; maybe even +1

NAO - Looks to stay positive; but would only be slight positive.

AO - Looks to jump to positive then in the LR I have no idea. Individual runs are all over the place.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/teleconnections.shtml

The long term looks below average, but the trough axis just stinks. Without a -NAO we can't get it further west.
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The long term looks below average, but the trough axis just stinks. Without a -NAO we can't get it further west.

 

The trough axis does stink, that's for sure, but the EPS does try to pull it back after day 12, could be typically EPS bias but this is what you would want to see for snow prospects to increase.   With the cold being shown after the 12th through early March it would really take some luck to not see some snow, IMO.  That's unfortunate, I would prefer the early spring.

post-2311-0-14441600-1423065982_thumb.pn

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The trough axis does stink, that's for sure, but the EPS does try to pull it back after day 12, could be typically EPS bias but this is what you would want to see for snow prospects to increase.   With the cold being shown after the 12th through early March it would really take some luck to not see some snow, IMO.  That's unfortunate, I would prefer the early spring.

Well that does look encouraging Pack.  

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Big Joe B feels the end game for this winter will be long and drawn out and gradually back into the plains.  No word on anything DC or south.

 

I don't think JB knows we exist unless a storm is originating down here to come his way.  The 12z GFS mutes pretty much anything major happening even in the long range.  This is a look that I actually like.

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The trough is to far east verbatim, but if this is the typical GEFS bias then this would be a very snow pattern for us, look at the -NAO going to town, with a big +PNA.  The look starts to develop day 8+.  The GEFS has done this a couple of times but all the modeling is agreeing on this, with support from the MJO too.  Will see, but if this looks does develop for a period of time then it will take some serious dodging to avoid snow (dodge, dip, dive, duck, and dodge)...

 

 

 

 

 

 

post-2311-0-13754700-1423072096_thumb.pn

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The trough is to far east verbatim, but if this is the typical GEFS bias then this would be a very snow pattern for us, look at the -NAO going to town, with a big +PNA.  The look starts to develop day 8+.  The GEFS has done this a couple of times but all the modeling is agreeing on this, with support from the MJO too.  Will see, but if this looks does develop for a period of time then it will take some serious dodging to avoid snow (dodge, dip, dive, duck, and dodge)...

Poor NE.  By the time this month is done, they will certainly be ready for spring.

 

It appears the trough may retrograde as the month wears on from it's position just east of us.  I hope we can score as it migrates and hope it's slow enough to give us a couple of opportunities.

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Big Joe B feels the end game for this winter will be long and drawn out and gradually back into the plains. No word on anything DC or south.

If u watched his video yesterday he showed winter picking up down further south starting next week and getting more active the further into feb. No he didn't say in our back yard but never does. Look at his winter forecast

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