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Winter 2014-2015 Pattern Discussion Thread I

LithiaWx

By LithiaWx,
in Southeastern States

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Cold Rain

Cold Rain

Posted
Posted

Yeah I agree.  I'm just grasping at anything to try a find a break in this crudy pattern.  It's amazing how consistent all the models are with the massive ridge dead in the heart of the US, and low heights at the pole (+AO pattern). 

 

Yeah, I'll just be glad when we start seeing a better pattern emerge in the guidance.  That's part of the fun of following this stuff.  It's no fun to pull up charts every day and see nothing but garbage showing up.  I know the LR is going to be shaky, but it would be nice to start seeing a cold pattern show its face.

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nflwxman

nflwxman

Posted
Posted

Yeah I agree.  I'm just grasping at anything to try a find a break in this crudy pattern.  It's amazing how consistent all the models are with the massive ridge dead in the heart of the US, and low heights at the pole (+AO pattern). 

Yep.  We will continue to see higher heights for the next week or two, but it may not fully translate to a daytime torch pattern due to the relatively high surface RH levels and a more juiced than normal SJS.

 

I would take much heart in seeing an active SJS at this point.  Aside from 2009-2010, most of our recent winters have seen below normal precip when it matters (Jan/Feb) due a negative PDO.  When the AO and NAO cooperate (it's when, not if), our chances for an ATL to PHL event increase dramatically.  Let's not forget, December 4-15th, is almost a month away from our true wheelhouse.  Patience is key here. 

 

Silver linings.

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FallsLake

FallsLake

Posted
Posted

Ok just a little bored with this pattern, so what do you guys think about a sneaky system hitting us early next week? Grasping at straws but nothing more to do..

 

http://mag.ncep.noaa.gov/Image.php?fhr=084ℑ=data%2Fnam%2F12%2Fnam_namer_084_500_vort_ht.gif&model=nam&area=namer&param=500_vort_ht&group=Model+Guidance&preselected_formatted_cycle_date=20141204+12+UTC&imageSize=M&ps=model

http://mag.ncep.noaa.gov/Image.php?fhr=084ℑ=data%2Fnam%2F12%2Fnam_namer_084_sim_radar.gif&model=nam&area=namer&param=sim_radar&group=Model+Guidance&preselected_formatted_cycle_date=20141204+12+UTC&imageSize=M&ps=model

http://www.twisterdata.com/index.php?prog=forecast&model=NAM&grid=221&model_yyyy=2014&model_mm=12&model_dd=04&model_init_hh=12&fhour=84&parameter=DPTF&level=2&unit=M_ABOVE_GROUND&maximize=n&mode=singlemap&sounding=n&output=image&view=large&archive=false

 

Edit: Looking at the 12GFS there are some big differences(compared to NAM) in the placement of the disturbance.  

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LithiaWx

LithiaWx

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Yep. We will continue to see higher heights for the next week or two, but it may not fully translate to a daytime torch pattern due to the relatively high surface RH levels due to a more juiced than normal SJS.

I would take much heart in seeing an active SJS at this point. Aside from 2009-2010, most of our winters have seen below normal precip when it matters (Jan/Feb). When the AO and NAO cooperate (it's when, not if), our chances for an ATL to PHL event increase dramatically. Let's not forget, December 4-15th, is almost a month away from our true wheelhouse. Patience is key here.

Silver linings.

Your thoughts are appreciated in here. Please continue to post. Our forum loves degreed mets who participate in discussions.
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buckeyefan1

buckeyefan1

Posted
Posted

Ok just a little bored with this pattern, so what do you guys think about a sneaky system hitting us early next week? Grasping at straws but nothing more to do..

 

http://mag.ncep.noaa.gov/Image.php?fhr=084ℑ=data%2Fnam%2F12%2Fnam_namer_084_500_vort_ht.gif&model=nam&area=namer&param=500_vort_ht&group=Model+Guidance&preselected_formatted_cycle_date=20141204+12+UTC&imageSize=M&ps=model

http://mag.ncep.noaa.gov/Image.php?fhr=084ℑ=data%2Fnam%2F12%2Fnam_namer_084_sim_radar.gif&model=nam&area=namer&param=sim_radar&group=Model+Guidance&preselected_formatted_cycle_date=20141204+12+UTC&imageSize=M&ps=model

http://www.twisterdata.com/index.php?prog=forecast&model=NAM&grid=221&model_yyyy=2014&model_mm=12&model_dd=04&model_init_hh=12&fhour=84&parameter=DPTF&level=2&unit=M_ABOVE_GROUND&maximize=n&mode=singlemap&sounding=n&output=image&view=large&archive=false

 

Edit: Looking at the 12GFS there are some big differences(compared to NAM) in the placement of the disturbance.  

Congrats SNE?  :P   

 

Seriously though......everyone needs to get outside these next 10-14 days and enjoy  :D   There is plenty of time to be locked up inside watching the model runs unfold.   :popcorn:

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Webberweather53

Webberweather53

Posted
Posted

I wouldn't be the least bit surprised to start seeing hype ramp up some over the coming week or two regarding the potential for a Stratospheric Warming Event in the longer ranges...

 

The GEM & GFS Ensembles as well as the CFSv2 have the classic precursor 500mb set-up to what is observed within 20 days or less in advance of stratospheric warming event. Here's what I mean by this...

 

 

 

gfs-ens_z500a5d_nhem_3.png

 

gem-ens_z500a5d_nhem_3.png

cfs-avg_z500a5d_nhem_3.png

The next 2 images were derived from pages 3 & 4 in a relatively short, but nice paper co-authored by Garfinkel (which seems to ring a bell) titled "Observed connection between stratospheric sudden warnings and the Madden Julian Oscillation"...

It should take you much less time to read this paper than my enormous post here, lol.

http://www.meteo.psu.edu/~sbf1/papers/Chaim_strat_paper.pdf

 

Amazing how similar the 11-15 day pattern is in much of the guidance to periods just in advance of sudden stratospheric warnings,  especially over the extreme North Pacific including Alaska, eastern Siberia, & the Aleutians...

Geopotential-Height-500mb-N-hem-SSWE-102

 

500mb-Height-Anomalies-Stratospheric-tem

Notice in the lower image + stratospheric temperature anomalies in the "polar cap region" closely follow in the wake of a phase 6-8 MJO pulse while the inverse is true for an upward MJO pulse driving into the eastern hemisphere (phases 1-3) & the interface of the positive & negative height anomalies & stratospheric temperatures in the "SSW precursor region" associated with the MJO is a little ways into phase 6, where the mean center of upward motion shifts well beyond the Maritime Continent & starts to impart vigorous large-scale upper level divergence that causes accelerations, wave packets, & jet streaks within the now more extensive Pacific Jet. The extension of the Pacific Jet coincides with an eastward displacement of its left exit region, where in synoptic scale cyclogenesis is favored w/ increased upper level divergence & poleward evacuation of air in the upper levels.

 

For those who may be struggling to understand how this concept of the eastward progression of the Aleutian Low works as it relates to jet streaks, I made this visual representation w/ demarcations to the regions (Left/Right Entrance/Exit) juxtaposed to a jet streak that will emerge over the next several days in the Pacific, and it assumes that one is upstream/behind (west of) the jet streak looking down towards it... Note when the Pacific Jet is extensive, the Aleutian Low is further east & stronger whereas a retraction of the Pacific Jet leads to a general weakening & northwestward displacement of the Aleutian Low...

Jet-Streak-Dynamics-Aleutian-Gulf-of-Ala

mslp_npac_30.gif

 

Going back how this relates to the MJO, an invigorated and amplified Rossby Wave train emanates from the origin of the anomalous convective/signal in upper level winds in west-central Pacific. This Rossby Wave train involves increased amplification of the semi-permanent Aleutian Low feature, ridging in the PNA region in & around western North America & subsequent toughing further east in North America. The weakened pressure /geopotential height (& thus also temperature) gradient downstream of East Asia, (where in the speeds of mid-latitude jet are climatologically the most intense)...

 

Mean 200mb Vector Wind

200mb-Vector-Wind-DJF-Northern-Hemispher

 

..results in a slow down of the polar night jet, due in part to the more robust Aleutian Low, leaving the polar vortex more vulnerable to upwelling intrusions & mixing of the ambient stratospheric air from underneath via synoptic-large scale Rossby/Planetary Waves. Thus, it’s quite common to observe following MJO progression into the Pacific, a net warming to transpire in the polar stratosphere as denoted by this image that lags stratosphere temps w/ phase 7 of the MJO

December-ENSO-MJO-phase-7-10-day-lag-str

 

...which if strong enough may lead to displacements & potentially even full-blown obliteration of the polar vortex that can promote crashes in the AO/NAM indices & ultimately favor outbreaks of arctic air into the mid-latitudes. 

 

In layman’s terms, sudden stratospheric warming events have a tendency to follow eastward MJO progression thru phases 6-8, (the late January 2010 sudden stratospheric warming is a classical example of this) which is where we are indeed headed over the next 1-2 weeks in terms of the MJO. I should mention not every Pacific MJO event is followed by a SSWE & it's entirely possible for this one not to result in a SSWE. However, given other parameters at hand & the fact that as HM mentioned on his twitter account the polar vortex will evolve from it's current barotropic mode (i.e. a compact, strong vortex with little notable warming) to a baroclinc regime where large temperature gradients across the polar stratosphere begin to develop. Although large certainties remain in terms of the precise timing & obviously the intensity of such an event, the threat for a SSWE will be generally on the rise as we get deeper into the 2nd half of December. 

EMON_phase_MANOM_51m_full.gif

 
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packbacker

packbacker

Posted
Posted

 

I wouldn't be the least bit surprised to start seeing hype ramp up some over the coming week or two regarding the potential for a Stratospheric Warming Event in the longer ranges...

 

 

 

 

 

 

Great writeup!  From the article you posted, I took the below snippet that was interesting...assuming the MJO dives back into COD and re-emerges in 4-7 around the 20th then early to mid January could look promising.

 

During days 13 to 24 before SSWs, MJO phases 4, 6, and 7 are preferred, while during days 25 to 36 before SSWs, MJO phases 2 and 3 are pre- ferred (Figures 1a and 1b). The lag between MJO phases 3 and 7 is consistent with the 30–60 day periodicity of the MJO 

 

 

post-2311-0-18911000-1417716890_thumb.pn

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buckeyefan1

buckeyefan1

Posted
Posted

 

I wouldn't be the least bit surprised to start seeing hype ramp up some over the coming week or two regarding the potential for a Stratospheric Warming Event in the longer ranges...

 

 

 

 

...which if strong enough may lead to displacements & potentially even full-blown obliteration of the polar vortex that can promote crashes in the AO/NAM indices & ultimately favor outbreaks of arctic air into the mid-latitudes. 

 

In layman’s terms, sudden stratospheric warming events have a tendency to follow eastward MJO progression thru phases 6-8, (the late January 2010 sudden stratospheric warming is a classical example of this) which is where we are indeed headed over the next 1-2 weeks in terms of the MJO. I should mention not every Pacific MJO event is followed by a SSWE & it's entirely possible for this one not to result in a SSWE. However, given other parameters at hand & the fact that as HM mentioned on his twitter account the polar vortex will evolve from it's current barotropic mode (i.e. a compact, strong vortex with little notable warming) to a baroclinc regime where large temperature gradients across the polar stratosphere begin to develop. Although large certainties remain in terms of the precise timing & obviously the intensity of such an event, the threat for a SSWE will be generally on the rise as we get deeper into the 2nd half of December. 

 

 

 

If wishes were fishes my tank would be full     :P    

 

In the mean time, enjoy the seasonal weather while it lasts   :lol:

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MichaelJ

MichaelJ

Posted
Posted

Great post Webber. I think the models will start sniffing out very soon (except maybe the GFS) the predicted pattern for this winter that had gotten most Meteorologists attention when making their cold winter forecasts for this year. Obviously nobody has a lock on what will happen but the set up is coming together for a lot of winter weather possibilities later this month and into January.

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deltadog03

deltadog03

Posted
Posted

I wish the MJO would cooperate though.  We don't need it to stay where it is now, or forecast to move then go back to where it is now.  I think the Typhoon is not going to re-curve.  Tells me the GFS is wrong, and that we will see some SE ridge flex at some point.  i.e., not like summer ridge stuff tho.

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griteater

griteater

Posted
Posted

More analog cold...yay, the best kind!

 

Here's Allan's 5h chart for the GFS Ensemble, averaged for the full model run, days 1-16

 

1z5oegx.gif

 

 

And here are December analogs that featured the combination of: 1) warm ENSO in the range of positive neutral to moderate El Nino, 2) moderate to high +PDO for Oct-Nov, and 3) a Gulf of Alaska Low.  Dec composite is very similar to GFS Ensemble map above...

 

1euw.png

 

 

Roll those analogs into Jan/Feb... 

 

8zjp4z.png

w1qq81.png

 

What I was most interested in was seeing how the Aleutian Low tends to move west during these types of +ENSO/+PDO winters, opening up the door for cold in the east.  Also, you see the increased arctic blocking, especially in Jan...along with -EPO Alaska ridging in Jan, and -EPO/+PNA ridging in Feb.  3 of the 5 winters (70, 03, 04) had a Major Midwinter Warming (i.e. a sudden stratospheric warming in Jan or Feb).

 

 

Here are the associated temp anomalies...

 

9pvmol.png

 

 

2yv08ja.png

 

 

14afuhz.png

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packbacker

packbacker

Posted
Posted

More analog cold...yay, the best kind!

 

Here's Allan's 5h chart for the GFS Ensemble, averaged for the full model run, days 1-16

 

 

 

 

And here are December analogs that featured the combination of: 1) warm ENSO in the range of positive neutral to moderate El Nino, 2) moderate to high +PDO for Oct-Nov, and 3) a Gulf of Alaska Low.  Dec composite is very similar to GFS Ensemble map above...

 

1euw.png

 

 

 

 

 

 

Compare it to the 5 day mean on the EPS for mid-Dec...

post-2311-0-97662400-1417726302_thumb.pn

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GaWx

GaWx

Posted
Posted

 Hot off of the press: week 4 of Euro weeklies (12/29-1/04) is cold in most of the E US with nearly 4 below normal SE, where the cold is centered. The E US, E Canada, and Greenland are the coldest in the N Hem.

 

 There is a strong +PNA and south of Aleutian low per 500 mb. The NAO is still positive, however, fwiw. That's why Greenland is also cold.

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GaWx

GaWx

Posted
Posted

Exxxxxcelent. 

 

Is there blocking showing up around, say Baffin Island? 

 

No, the above normal heights are centered on Alaska and W N.A. (+PNAish).

 

The strongest +500 mb ht. anomalies are over W Canada and AK.

 

AO is ~neutral. +NAO.

 

 I'm thrilled about the map (though not surprised), especially since it is following analogs pretty nicely! Finally some good modeling news though it is not til week 4.

 

 This forum could use news like this. It has been kind of depressing to come here of late. ;)

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SnowNiner

SnowNiner

Posted
Posted

No, the above normal heights are centered on Alaska and W N.A. (+PNAish).

 

The strongest +500 mb ht. anomalies are over W Canada and AK.

 

AO is ~neutral. +NAO.

 

 I'm thrilled about the map (though not surprised), especially since it is following analogs pretty nicely! Finally some good modeling news though it is not til week 4.

 

 This forum could use news like this. It has been kind of depressing to come here of late. ;)

 

Ok, I'll take it.  At least it would be a change in the pattern and a cold one.  Thanks. 

 

Step two must be a -NAO though.  Maybe that will be next week's week 4!!  I'm going to go ahead and take it as gospel that what's shown is going to happen.  Analogs say so, so yeah.  :weenie:

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deltadog03

deltadog03

Posted
Posted

 Hot off of the press: week 4 of Euro weeklies (12/29-1/04) is cold in most of the E US with nearly 4 below normal SE, where the cold is centered. The E US, E Canada, and Greenland are the coldest in the N Hem.

 

 There is a strong +PNA and south of Aleutian low per 500 mb. The NAO is still positive, however, fwiw. That's why Greenland is also cold.

Thanks Larry...nice to hear all of that.  Apparently the JMA came in about the same as well...

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packbacker

packbacker

Posted
Posted

No, the above normal heights are centered on Alaska and W N.A. (+PNAish).

The strongest +500 mb ht. anomalies are over W Canada and AK.

AO is ~neutral. +NAO.

I'm thrilled about the map (though not surprised), especially since it is following analogs pretty nicely! Finally some good modeling news though it is not til week 4.

This forum could use news like this. It has been kind of depressing to come here of late. ;)

The NAO looks more neutral to me, but it's a great look. Xmas eve things flip cold and are really cold for the east the last 12 days of the run. This should start coming into range of the EPS this weekend.

Edit: I just the WSI week 4 and see the -NAO. Interesting the WB maps aren't more neutral but doesn't matter.

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MichaelJ

MichaelJ

Posted
Posted

I really think the NAO is much more important for us later in the season than it is now. Also I think the reason for the Aleutian low to retrograde during this type (Modoki El Nino/+PDO) regime may be due to the way they cause the pressures to change from their normal locations. Kind of like an external forcing if you will, but that is just conjecture on my part

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Webberweather53

Webberweather53

Posted
Posted

Great writeup!  From the article you posted, I took the below snippet that was interesting...assuming the MJO dives back into COD and re-emerges in 4-7 around the 20th then early to mid January could look promising.

 

During days 13 to 24 before SSWs, MJO phases 4, 6, and 7 are preferred, while during days 25 to 36 before SSWs, MJO phases 2 and 3 are pre- ferred (Figures 1a and 1b). The lag between MJO phases 3 and 7 is consistent with the 30–60 day periodicity of the MJO 

 

Great post Webber. I think the models will start sniffing out very soon (except maybe the GFS) the predicted pattern for this winter that had gotten most Meteorologists attention when making their cold winter forecasts for this year. Obviously nobody has a lock on what will happen but the set up is coming together for a lot of winter weather possibilities later this month and into January.

 

I wish the MJO would cooperate though.  We don't need it to stay where it is now, or forecast to move then go back to where it is now.  I think the Typhoon is not going to re-curve.  Tells me the GFS is wrong, and that we will see some SE ridge flex at some point.  i.e., not like summer ridge stuff tho.

 

 

Yeah, IMO, the clock is ticking & it's only a matter of time... The ongoing cold striking/loading into Eurasia in December is the first phase of high snowpack winter, North America is usually next in line in January & this is supported by a multitude of analog packages & the conditions at hand, like the record northern hemisphere snowpack...

 

I'm having difficulty in seeing how we're going to walk away from this one empty handed. As one would expect, the correlation to US winter temps gets stronger as you focus on winters further up the list, w/ the top 5 (behind this year of course) (including last year) looking quite frigid & according to the 1981-2010 climatology, the first above normal winter on the list is 1973-74, a distant 8th place...

 

Top-20-10-5-US-Winter-temps-Fall-Norther

I made a post about this yesterday & the years we're lined up w/ in this department were very impressive & quite cold...

 

Combined Sep+Oct+Nov Eurasian, North America (w/o Greenland), & Northern hemisphere snowfall (combined) is currently also a record, beating out 1976. Amazing...

 

Here are the top 20 years

 

Year            Total Snow (Million Sq. Km)

2014 126.93

1976 124.94

1972 124.23

2002 123.13

2013 118.07

1993 118.02

1970 117.96

1973 115.63

1996 115.60

2012 115.59

2009 113.78

2000 113.68

1985 113.40

2011 112.53

1998 112.18

1968 112.07

2006 111.59

2004 111.53

2003 111.41 

1997 111.34

 

The regressed 500mb for DJF following years with high SON northern hemisphere snowpack looks all too familiar, lots of high latitude blocking, strong Aleutian/Gulf of Alaskan Low...

N-hem-Winter-500mb-regressed-Sep-Nov-Sno

In reference to my previous comment, I did like the article, short, sweet and to the point. There's a lot of literature out there on the MJO's connection to the AO/NAO, you just have to do a little digging...

 

 

http://iprc.soest.hawaii.edu/users/natj/papers/Riddle_etal_2013.pdf

 

http://www.atmos.albany.edu/facstaff/roundy/convection/Walich14.pdf

 

http://www.readcube.com/articles/10.1002/2014GL061094

 

http://www.meteo.mcgill.ca/~swson/papers/Seo-Son-JAS2011.pdf

 

Specifically for general information on the MJO, Equatorial Waves, & the QBO, these 3 papers are the best I've come across to date & they are lengthy, but provide you with the necessary foundation to build off of to understand other related concepts...

 

Madden Julian Oscillation

http://onlinelibrary.wiley.com/store/10.1029/2004RG000158/asset/rog1614.pdf?v=1&t=i3at08sy&s=5b0085dbbf1ed9843b6fb823a9e583c8f97f62a2

 

Convectively Coupled Equatorial Waves

http://www.atmos.albany.edu/daes/atmclasses/atm421/Reference_Material_files/Kiladisetal2009.pdf

 

Quasi-Biennial Oscillation

http://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=8A3934D7A70F2C70BCAC5BFB51497129?doi=10.1.1.144.305&rep=rep1&type=pdf

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