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MJO/LR Forecasting Thread


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#51
Phil

Posted 23 November 2014 - 03:07 PM

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Given the warm SST's, the MJO cycle duration is at it's shortest, around 30-40 days. Lack of convective budget with a weak walker cell increases the propagation speed.


Love your posts..you're really tearing it up. Agreed that mean period frequency has been elevated over the last 3-4 months due to ENSO/QBO forcing on eddy transport.

What are you referring to when you mention the lack of a convective budget? I get that SST anomalies are somewhat uniform longitudinally for a Niño (destabilizes Walker-Hadley intensity ratio), but the tropical tropopause is higher than normal, and macroscale mixing is quite deep.

At this point, I say our window of opportunity is ~Dec 1-10 while the MJO is centered around the Maritime Continent. After that, convection moves into the Pacific, with cold favoring the Central US at first, then shifting into the East. What happens from there is up in the air. Not saying we can't see any cold, just that tropical forcing favors warmth in the west for 2/3 of December. If a new MJO wave initiates over the IO, given the current MJO duration, early-mid January could be our next major window of opportunity, which lines up with the LRC so far this season. I was linked a great article by @webberweather, which illustrates the MJO cycle duration by month. Keep in mind, as mentioned above, cycle duration is on the low end this season.

http://journals.amet...1175/JCLI4230.1

SLq3wCl.jpg


Great analysis! Best of luck to you here. Personally I favor January over December. I agree with your thoughts on the longwave progression, but I suspect most of December will be highly zonal due to the observed poleward AAM transport since September and the near record low in the Walker-Hadley intensity ratio. Biggest question for me is in the timing of the SSW/PVA implosion..whenever it occurs, it'll lead to extreme cold for at least 3-5 weeks, I suspect..
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Cold season 2017/18:
Snowfall: 0"
Largest snowfall: 0"
Number of winter events: 0
Coldest High 67*F
Coldest low: 44*F
Highest sustained wind: 17mph
Highest wind gust: 26mph

#52
snow_wizard

Posted 23 November 2014 - 03:25 PM

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Definitely looks like a tight gradient on a few of the model runs. The northern locations may get lucky, but it's borderline at this point. Given the warm SST's, the MJO cycle duration is at it's shortest, around 30-40 days. Lack of convective budget with a weak walker cell increases the propagation speed. 
 
At this point, I say our window of opportunity is ~Dec 1-10 while the MJO is centered around the Maritime Continent. After that, convection moves into the Pacific, with cold favoring the Central US at first, then shifting into the East. What happens from there is up in the air. Not saying we can't see any cold, just that tropical forcing favors warmth in the west for 2/3 of December. If a new MJO wave initiates over the IO, given the current MJO duration, early-mid January could be our next major window of opportunity, which lines up with the LRC so far this season. I was linked a great article by @webberweather, which illustrates the MJO cycle duration by month. Keep in mind, as mentioned above, cycle duration is on the low end this season.


Wow! You're digging into this stuff deeper than I do. One thing I did notice with the ECMWF MJO forecast is the possibility of the MJO getting much weaker as it approaches octant 6. If so it could collapse and re-emerge in a good location for us. I hope the waves progressing so quickly doesn't mean any windows of opportunity for us this winter will be quite short.

Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#53
Snow

Posted 24 November 2014 - 03:18 PM

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The new EURO MJO Index Forecast from Nov. 24 to Dec. 8.  Looks like the Southwest will be cooler than normal until the end of Phase 6. Models show this will be true as a cool system will bring significant rain to So. Cal and keep the entire SW cool. Phase 7 is what I'm keeping a close eye on as of right now. Phase 7 will be cooler/colder for the PNW with a decently high significance % and strong signal. My confidence is growing that we could a significant arctic air at this time. From the EURO MJO it looks like we will hit Phase 7 on Dec. 8 but not be there for long, maybe until Dec. 11? Still long ways away to pinpoint the exact duration of being in Phase 7. My only concern is that if we blast right through Phase 7 quickly is that all we see is a backdoor event as the majority of the arctic air slides east. Then Phase 8 will be warmer but once we get back to Phase 1/2 we should have another chance of arctic air. The EURO MJO correctly predicted our arctic backdoor event two weeks ago when we were in Phase 1 with a strong signal. Significance % not very high in Phase 1 like before so Phase 2 looks more likely. I'm sticking to my initial forecast of arctic air sometime during the last 10 days of December and my confidence is higher now that we might see something more than a backdoor event at that time.

 

As a side note notice how Phase 3 shows colder air along the east coast depicting the Nor'easter that they will see this weekend. After that Phase 4 to Phase 7 will be warm and the significant % is very high showing this as a near lock for them. Phase 8 will finally end it and bring them arctic air through the end of Phase 2.

 

ECMF_phase_MANOM_51m_full.gif

combined_image.png



#54
Bryant

Posted 25 November 2014 - 11:21 PM

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Love your posts..you're really tearing it up. Agreed that mean period frequency has been elevated over the last 3-4 months due to ENSO/QBO forcing on eddy transport.

What are you referring to when you mention the lack of a convective budget? I get that SST anomalies are somewhat uniform longitudinally for a Niño (destabilizes Walker-Hadley intensity ratio), but the tropical tropopause is higher than normal, and macroscale mixing is quite deep.


Great analysis! Best of luck to you here. Personally I favor January over December. I agree with your thoughts on the longwave progression, but I suspect most of December will be highly zonal due to the observed poleward AAM transport since September and the near record low in the Walker-Hadley intensity ratio. Biggest question for me is in the timing of the SSW/PVA implosion..whenever it occurs, it'll lead to extreme cold for at least 3-5 weeks, I suspect..

 

Hey Phil,

 

Took forever to respond, sorry about that. When I mentioned "convective budget", I was simply referring to the amount of convection currently in the tropics. From the papers I've read, a "wet" convective regime will slow down an MJO wave, and a "dry" suppressed regime speeds it up. This goes for La Nina's and El Nino's in general, as the MJO propagates quicker in El Nino's vs La Nina's. Still digging into research and far as the reasoning behind this however. 

 

I tend to favor January over December as well, purely due to more available cold. However, this MJO wave looks to deliver the cold as expected. I'm curious to see if we still see another cold shot begin to show on the models while the tropical forcing is still around the MC. Definite possibility.



#55
Bryant

Posted 25 November 2014 - 11:27 PM

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Wow! You're digging into this stuff deeper than I do. One thing I did notice with the ECMWF MJO forecast is the possibility of the MJO getting much weaker as it approaches octant 6. If so it could collapse and re-emerge in a good location for us. I hope the waves progressing so quickly doesn't mean any windows of opportunity for us this winter will be quite short.

 

Wanted to touch base on the ECMWF forecast you mentioned. As with any forecast, data becomes less reliable the further in time you go. Often times, the MJO wave is shown to die off in the dynamical forecasts, only to strengthen as we get closer. As far as our windows of opportunity, you may have a point. However, given the warm SST's and El Nino regime, the MJO propagates much quicker, resulting in more potential shots of cold. We saw cold in November, and now cold is coming for the beginning of December. Will January be the memorable month this year? 


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#56
Bryant

Posted 25 November 2014 - 11:49 PM

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The new EURO MJO Index Forecast from Nov. 24 to Dec. 8.  Looks like the Southwest will be cooler than normal until the end of Phase 6. Models show this will be true as a cool system will bring significant rain to So. Cal and keep the entire SW cool. Phase 7 is what I'm keeping a close eye on as of right now. Phase 7 will be cooler/colder for the PNW with a decently high significance % and strong signal. My confidence is growing that we could a significant arctic air at this time. From the EURO MJO it looks like we will hit Phase 7 on Dec. 8 but not be there for long, maybe until Dec. 11? Still long ways away to pinpoint the exact duration of being in Phase 7. My only concern is that if we blast right through Phase 7 quickly is that all we see is a backdoor event as the majority of the arctic air slides east. Then Phase 8 will be warmer but once we get back to Phase 1/2 we should have another chance of arctic air. The EURO MJO correctly predicted our arctic backdoor event two weeks ago when we were in Phase 1 with a strong signal. Significance % not very high in Phase 1 like before so Phase 2 looks more likely. I'm sticking to my initial forecast of arctic air sometime during the last 10 days of December and my confidence is higher now that we might see something more than a backdoor event at that time.

 

As a side note notice how Phase 3 shows colder air along the east coast depicting the Nor'easter that they will see this weekend. After that Phase 4 to Phase 7 will be warm and the significant % is very high showing this as a near lock for them. Phase 8 will finally end it and bring them arctic air through the end of Phase 2.

 

I love the work you put into these posts! I love seeing the feedback I've seen so far with this thread, and having someone else make forecasts alongside me using the MJO is a great learning experience for the both of us. As far as the rest of the month goes, I've had the 1-10th as my time frame for cold for a while now. I'm still waiting for the models to show a solid secondary shot of cold air, as I think it's a definite possibility. The last 2/3 of the month in my opinion will be pretty dull, with the bulk of the cold East of the Rockies. Keep in mind, that the CPC composites you use aren't 100% the way to go. There are other resources out there as well, and I try to make the best of all of them. I'm hoping the MJO shows signs of a new wave once this wave dies off, then we can begin estimating our time frame for January 


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#57
Black Hole

Posted 26 November 2014 - 11:45 AM

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Anybody know if the MJO maps are on weather bell for the ECMWF at all?


BS Atmospheric Science University of Utah May 2015

PhD Candidate Atmospheric Sciences

 

--Emphasis on: Forecasting, Mountain Weather, Numerical Weather Prediction, Data Assimilation

 

Winter 2016/17 Snow:
Nov 17: 3.2", 23: 1.6", 28: 9.2" (14)

Dec 1: .5", 16: 2.5", 25: 13" (16)

Jan 2: 5", 3: 2.4", 4: 7.7", 12: 1", 19: 1.2", 21: 13", 23: 6", 24: 1", 25: 3.7", 26: 2.5" (43.5) 

Feb 11: .5", 23: 6.5", 27: 4.5" (13.5)

Mar 5: 5.5" (5.5)

Apr 8: 2", 9: 1.8" (3.8)

May 17: 1" (1)
Total: 96.3"

Lowest Temp: 2F


#58
Black Hole

Posted 26 November 2014 - 11:54 AM

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Wanted to touch base on the ECMWF forecast you mentioned. As with any forecast, data becomes less reliable the further in time you go. Often times, the MJO wave is shown to die off in the dynamical forecasts, only to strengthen as we get closer. As far as our windows of opportunity, you may have a point. However, given the warm SST's and El Nino regime, the MJO propagates much quicker, resulting in more potential shots of cold. We saw cold in November, and now cold is coming for the beginning of December. Will January be the memorable month this year? 

Is the MJO usually more robust in el nino? It seems to be pretty strong and moving quickly for now.

 

I love the work you put into these posts! I love seeing the feedback I've seen so far with this thread, and having someone else make forecasts alongside me using the MJO is a great learning experience for the both of us. As far as the rest of the month goes, I've had the 1-10th as my time frame for cold for a while now. I'm still waiting for the models to show a solid secondary shot of cold air, as I think it's a definite possibility. The last 2/3 of the month in my opinion will be pretty dull, with the bulk of the cold East of the Rockies. Keep in mind, that the CPC composites you use aren't 100% the way to go. There are other resources out there as well, and I try to make the best of all of them. I'm hoping the MJO shows signs of a new wave once this wave dies off, then we can begin estimating our time frame for January 

Based off of what we are seeing above on the ECMWF forecast it could be in phase 8 by Dec 10th or so and into phases 1-2 shortly after. At least according to SNOW's composites that would put cold and perhaps snow in the Dec 10-20 timeframe instead of 1-10. What is leading you to say the 1-10 could be interesting?


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BS Atmospheric Science University of Utah May 2015

PhD Candidate Atmospheric Sciences

 

--Emphasis on: Forecasting, Mountain Weather, Numerical Weather Prediction, Data Assimilation

 

Winter 2016/17 Snow:
Nov 17: 3.2", 23: 1.6", 28: 9.2" (14)

Dec 1: .5", 16: 2.5", 25: 13" (16)

Jan 2: 5", 3: 2.4", 4: 7.7", 12: 1", 19: 1.2", 21: 13", 23: 6", 24: 1", 25: 3.7", 26: 2.5" (43.5) 

Feb 11: .5", 23: 6.5", 27: 4.5" (13.5)

Mar 5: 5.5" (5.5)

Apr 8: 2", 9: 1.8" (3.8)

May 17: 1" (1)
Total: 96.3"

Lowest Temp: 2F


#59
Bryant

Posted 28 November 2014 - 02:00 AM

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Is the MJO usually more robust in el nino? It seems to be pretty strong and moving quickly for now.

Based off of what we are seeing above on the ECMWF forecast it could be in phase 8 by Dec 10th or so and into phases 1-2 shortly after. At least according to SNOW's composites that would put cold and perhaps snow in the Dec 10-20 timeframe instead of 1-10. What is leading you to say the 1-10 could be interesting?


Earlier forecasts had the MJO centered around the Maritime Continent until ~10th, which is where the original call came from. Now however, the MJO looks to enter the west pacific earlier than thought, closing our window of opportunity. I also have learned a bit more about the MJO based off my own composites, which I discuss below. This is all still a learning process, and I'll definitely make mistakes, but that's how we all learn right?

As far as December is concerned, I'm quite curious as to what will actually happen. CFS has a torch for the whole month, while the teleconnectors paint a different story. The below composite features dates in which the AO was between -3 and 1, the PNA was between .5 and 2, during a >0 ENSO during the month of December. As you see, a trough should be a definite feature in the east after the 1st week of December based off tele's.

Eb4D742.gif
GFj3l1j.gif



As far as the MJO, my gut would tell me that the core of cold would transfer to east of the Rockies, due to convection further east, causing mean ridge and trough to shift east as well. If you follow any of the same people I follow on twitter, they are all singing the same tune... MJO in phase 7/8 = return of the cold (for the east).

2VFtdJx.jpg
E89amp0.jpg
DwFgDSR.jpg


CPC MJO phase maps
5LAwzJF.jpg

I'm really curious as to how the last 1/2 of this month turns out honestly. I made some of my own composites to take a look at phase 7/8 myself, however, noticed some big differences between the above image, and my own results. After looking further into it, it appears based off history, the MJO plays a much bigger role on our weather pattern come Jan and Feb. Jan phases 7/8 look much more like I'd expect them to look given the position of tropical forcing, leading me to believe other factors are much more at play this month. I'm also going to conclude that this coming cold spell won't be as long lasting as I had originally thought, due to MJO not playing as big of a role as I realized early in winter.

Hrpnyuf.gif



Final thoughts for December....

Although the above image shows cold for the West in phase 7 during December, I don't feel we'll see anything close to that verifying. Other factors are at play here, and with the tele's heading where they are, the cold will most likely return to the east until further notice with a strong +PNA pattern locked in. If we're going to see any cold in the next few weeks (besides the obvious), it would most likely be a backdoor type event if anything. While we can reevaluate in 2-3 weeks from now, I'm not hopeful for December currently. Hope I eat my words here in 2 weeks :unsure:

B9q2RFG.gif

#60
Snow

Posted 29 November 2014 - 05:41 PM

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I love the work you put into these posts! I love seeing the feedback I've seen so far with this thread, and having someone else make forecasts alongside me using the MJO is a great learning experience for the both of us. As far as the rest of the month goes, I've had the 1-10th as my time frame for cold for a while now. I'm still waiting for the models to show a solid secondary shot of cold air, as I think it's a definite possibility. The last 2/3 of the month in my opinion will be pretty dull, with the bulk of the cold East of the Rockies. Keep in mind, that the CPC composites you use aren't 100% the way to go. There are other resources out there as well, and I try to make the best of all of them. I'm hoping the MJO shows signs of a new wave once this wave dies off, then we can begin estimating our time frame for January 

 

Thanks for the love. Yeah the CPC isn't 100%, it will be interesting to see how December plays out in regards to how we progress through the MJO Phases and what the resulting weather will be.



#61
Bryant

Posted 29 November 2014 - 06:57 PM

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Thanks for the love. Yeah the CPC isn't 100%, it will be interesting to see how December plays out in regards to how we progress through the MJO Phases and what the resulting weather will be.


As I mentioned above in the new post, the 1-10 timeframe I mentioned will be a bust. MJO progressed much quicker than I originally thought. Dec should be dominated by a +PNA pattern with a -NAO developing around mid month due to MJO moving into the West Pacific.

#62
snow_wizard

Posted 30 November 2014 - 11:29 AM

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No doubt the MJO came through for us again.  I have no doubt our current bout of winter was brought on by that.  Usually a good wave will bring us something fun somewhere in the 3 - 7 area.  As others have pointed out factors that work in conjunction with the MJO and time of year effect what octant will deliver the goods.


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#63
snow_wizard

Posted 30 November 2014 - 11:30 AM

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The ECMWF insists the current wave will die before reaching region 6.


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#64
Phil

Posted 30 November 2014 - 11:40 AM

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There's some competition in the tropics now, I believe, which should be noted. There's some higher-frequency behavior in the velocity data, indicating CCKW activity to some extent. The MJO signal is weakening somewhat, however the phase diagrams may be slightly contaminated, for now.
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Cold season 2017/18:
Snowfall: 0"
Largest snowfall: 0"
Number of winter events: 0
Coldest High 67*F
Coldest low: 44*F
Highest sustained wind: 17mph
Highest wind gust: 26mph

#65
snow_wizard

Posted 30 November 2014 - 12:02 PM

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I'm getting really frustrated that the AAM data hasn't been updated for over a week now.


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#66
Phil

Posted 30 November 2014 - 01:21 PM

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I'm getting really frustrated that the AAM data hasn't been updated for over a week now.


The scientist who plotted much of the AAM et al data has retired, unfortunately. I might be taking over the job :lol:
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Cold season 2017/18:
Snowfall: 0"
Largest snowfall: 0"
Number of winter events: 0
Coldest High 67*F
Coldest low: 44*F
Highest sustained wind: 17mph
Highest wind gust: 26mph

#67
snow_wizard

Posted 30 November 2014 - 02:18 PM

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The scientist who plotted much of the AAM et al data has retired, unfortunately. I might be taking over the job :lol:

 

Are you serious?  Was that Ed Berry or Klaus Weickmann?

 

So the person retired and they have just left nobody to do it?  Geeze.  I'm also wondering if there will be any way to go back and recreate all of the data from the missing days.


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#68
Phil

Posted 01 December 2014 - 10:59 AM

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Are you serious? Was that Ed Berry or Klaus Weickmann?

So the person retired and they have just left nobody to do it? Geeze. I'm also wondering if there will be any way to go back and recreate all of the data from the missing days.


Lol, I didn't mean the actual job, but I'm thinking of taking the data and plotting it myself. I used that page on a semi-regular basis..wouldn't be too difficult with the right software.
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Cold season 2017/18:
Snowfall: 0"
Largest snowfall: 0"
Number of winter events: 0
Coldest High 67*F
Coldest low: 44*F
Highest sustained wind: 17mph
Highest wind gust: 26mph

#69
Bryant

Posted 02 December 2014 - 11:36 AM

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Talk about LR models hinting at cold towards the end of December got me thinking. Around Nov 10th, right as the MJO gained amplitude into region 8/1, the PNW had a backdoor cold event. Could this be a possibility as the MJO propagates east over the Pacific towards the Western Hemisphere? Not likely. Not only do MJO cycles lengthen as we progress towards winter, their influences vary month to month as well

 

rvDvxHB.jpg


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#70
Phil

Posted 02 December 2014 - 11:47 AM

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Awesome post. Might be important to note that the phase diagrams are heavily contaminated right now..they've been messing with a lot of people lately..even pro mets who don't isolate the velocity frequencies and misplace the MJO as a result. Here's a post I recently wrote in the main PNW thread:



For those looking at the MJO phase diagrams, keep in mind there's a lot of CCKW contamination ongoing...the real MJO is not that amplified, and has not progressed that far eastward yet..the MJO wave itself doesn't look favored to progress past region 7-8, assuming it gets there..? Walker/Hadley I/R looks blah..

Tropical forcing won't favor a -EPO/-NAO until the last week of December..the +PNA should flip later..


So, yeah, I suspect the next 20-25 days will look fairly zonal over the lower-48
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Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Cold season 2017/18:
Snowfall: 0"
Largest snowfall: 0"
Number of winter events: 0
Coldest High 67*F
Coldest low: 44*F
Highest sustained wind: 17mph
Highest wind gust: 26mph

#71
Bryant

Posted 02 December 2014 - 12:47 PM

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Awesome post. Might be important to note that the phase diagrams are heavily contaminated right now..they've been messing with a lot of people lately..even pro mets who don't isolate the velocity frequencies and misplace the MJO as a result. Here's a post I recently wrote in the main PNW thread:




So, yeah, I suspect the next 20-25 days will look fairly zonal over the lower-48

 

I agree that the overall theme for 2/3 of December will be zonal. Also, the CCKW definitely alters the phase diagrams, causing the MJO to travel much quicker than it will. I'm curious as to why you feel the MJO may not even make it to 7/8? The warm SST's stretch clear to the Western Hemisphere, leaving an easy path for the MJO to propagate to.  

 

I know composites based off lag times aren't the best, but more evidence supporting zonal flow across the US followed by a crash in the NAO

 

RvURaCd.gif



#72
Phil

Posted 02 December 2014 - 01:58 PM

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Agreed on the SSTs...I'm not confident the MJO will complete a full propagation intact due to potentially detrimental effects of the CCKW activity on the low-freq MJO cell, and possibly the effects of the final warming event in ongoing over the SH stratosphere...could impact the Hadley Cells during the initial +SAM response?
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Cold season 2017/18:
Snowfall: 0"
Largest snowfall: 0"
Number of winter events: 0
Coldest High 67*F
Coldest low: 44*F
Highest sustained wind: 17mph
Highest wind gust: 26mph

#73
Bryant

Posted 02 December 2014 - 02:21 PM

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Agreed on the SSTs...I'm not confident the MJO will complete a full propagation intact due to potentially detrimental effects of the CCKW activity on the low-freq MJO cell, and possibly the effects of the final warming event in ongoing over the SH stratosphere...could impact the Hadley Cells during the initial +SAM response?


It does appear the CCKW and MJO are traveling in tandem right now, what that will cause down the road though I'm unsure of. If only tropical forcing was an easier subject to learn =P

#74
Phil

Posted 02 December 2014 - 02:36 PM

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It does appear the CCKW and MJO are traveling in tandem right now, what that will cause down the road though I'm unsure of. If only tropical forcing was an easier subject to learn =P


I'm still learning too, lol. I'm guessing it's a battle between SSTs/antecedent Niño inertia (Walker/Hadley intensity ratio(s)) versus the stratosphere and the higher-frequency instabilities? What are your thoughts on all this? Your guess is as good as mine on this :)
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Cold season 2017/18:
Snowfall: 0"
Largest snowfall: 0"
Number of winter events: 0
Coldest High 67*F
Coldest low: 44*F
Highest sustained wind: 17mph
Highest wind gust: 26mph

#75
Bryant

Posted 02 December 2014 - 03:09 PM

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I'm still learning too, lol. I'm guessing it's a battle between SSTs/antecedent Niño inertia (Walker/Hadley intensity ratio(s)) versus the stratosphere and the higher-frequency instabilities? What are your thoughts on all this? Your guess is as good as mine on this :)


I'll get back to you.... *goes to do research*
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#76
Chris

Posted 03 December 2014 - 04:23 PM

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Read through a paper discussing a MJO / SSW correlation... Quite interesting

http://www.meteo.psu...strat_paper.pdf


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#77
Bryant

Posted 03 December 2014 - 05:03 PM

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Read through a paper discussing a MJO / SSW correlation... Quite interesting

http://www.meteo.psu...strat_paper.pdf


Thanks Chris :)

#78
Black Hole

Posted 03 December 2014 - 06:43 PM

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That paper would suggest a SSW would be possible in 13-24 days from now, or mid-late December. I suppose that is similar to what some have been saying.


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BS Atmospheric Science University of Utah May 2015

PhD Candidate Atmospheric Sciences

 

--Emphasis on: Forecasting, Mountain Weather, Numerical Weather Prediction, Data Assimilation

 

Winter 2016/17 Snow:
Nov 17: 3.2", 23: 1.6", 28: 9.2" (14)

Dec 1: .5", 16: 2.5", 25: 13" (16)

Jan 2: 5", 3: 2.4", 4: 7.7", 12: 1", 19: 1.2", 21: 13", 23: 6", 24: 1", 25: 3.7", 26: 2.5" (43.5) 

Feb 11: .5", 23: 6.5", 27: 4.5" (13.5)

Mar 5: 5.5" (5.5)

Apr 8: 2", 9: 1.8" (3.8)

May 17: 1" (1)
Total: 96.3"

Lowest Temp: 2F


#79
snow_wizard

Posted 03 December 2014 - 07:59 PM

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The ECMWF insists the MJO wave will soon collapse with a strong re-emergence into octant 4 at the end of week 2.  If so the models showing a cold West around Christmas could be right.


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#80
Phil

Posted 03 December 2014 - 08:38 PM

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The ECMWF insists the MJO wave will soon collapse with a strong re-emergence into octant 4 at the end of week 2. If so the models showing a cold West around Christmas could be right.


Those phase diagrams are heavily contaminated right now..that has almost no chance of happening..
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Cold season 2017/18:
Snowfall: 0"
Largest snowfall: 0"
Number of winter events: 0
Coldest High 67*F
Coldest low: 44*F
Highest sustained wind: 17mph
Highest wind gust: 26mph

#81
snow_wizard

Posted 03 December 2014 - 09:27 PM

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Those phase diagrams are heavily contaminated right now..that has almost no chance of happening..

 

We'll see.  Regardless of noise or whatever the ECMWF has been calling the MJO pretty well lately and this latest wave did deliver for us.  I think late December is possible for cold here, although I think Jan is more likely.


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#82
Bryant

Posted 03 December 2014 - 11:20 PM

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Pineapple express you say? Allow the MJO to explain... 

 

tV0W510.gif



#83
daniel1

Posted 04 December 2014 - 07:20 AM

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The ECMWF insists the MJO wave will soon collapse with a strong re-emergence into octant 4 at the end of week 2.  If so the models showing a cold West around Christmas could be right.

Why are you so insistent on this?



#84
snow_wizard

Posted 04 December 2014 - 05:59 PM

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Why are you so insistent on this?

 

 

For one it's pretty atypical behavior for warm ENSO.  Secondly...if the MJO behaves like the ECMWF is indicating we could easily see cold weather in the NW again before New Years.  Maritime Continent is usually good for us.


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#85
Phil

Posted 04 December 2014 - 06:13 PM

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MEI is back up to +0.712..El Niño is here and has been for awhile..
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Cold season 2017/18:
Snowfall: 0"
Largest snowfall: 0"
Number of winter events: 0
Coldest High 67*F
Coldest low: 44*F
Highest sustained wind: 17mph
Highest wind gust: 26mph

#86
daniel1

Posted 04 December 2014 - 06:58 PM

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For one it's pretty atypical behavior for warm ENSO. Secondly...if the MJO behaves like the ECMWF is indicating we could easily see cold weather in the NW again before New Years. Maritime Continent is usually good for us.

I think it will reemerge into phase 7-8 by late dec

#87
Bryant

Posted 04 December 2014 - 08:18 PM

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I think it will reemerge into phase 7-8 by late dec

 

Welcome Daniel! I'm in agreement with this. The RMM index tends to lose the OLR signal as we approach the central to eastern Pacific. The MJO has also been trailing a CCKW over the Maritime Continent, but as the 2 waves separate from each other, the "noise" causes the the RMM index to send the MJO into the COD. Just because the RMM index loses the signal, definitely doesn't mean the MJO isn't propagating through the Pacific. The RMM index will either catch onto the MJO once the noise is out of the picture, or it will remain as a weak wave as it typically does towards the Western Hemisphere. 

 

NmAO7NJ.gif



#88
snow_wizard

Posted 04 December 2014 - 08:46 PM

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This will be interesting to watch.  I can't imagine the ECMWF being so far off, but who knows.


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#89
Bryant

Posted 10 December 2014 - 01:49 PM

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I'm on mobile so won't be typing a whole lot, but wanted to update this thread briefly. I hate to say it, but I still don't see any signs of cold in the near future, but I pretty much wrote off December before it even started.

As Phil has mentioned many times, the RMM plots cannot be trusted currently for tracking the MJO. The MJO is alive and well over the Pacific, regardless of the RRM index bringing it into the COD. Reason being, a CCKW has detached from the MJO which were in tandem for a while over the MC. The CCKW is now well into the western Hemisphere, while the MJO has just pushed out into the Pacific. RMM index's use OLR alongside upper and lower level winds to track the MJO. As the MJO propagates towards the western Hemisphere, it loses it's OLR signal, often resulting in missed MJO events over the central to western Pacific.

Jim has mentioned the Euro MJO reemerging over the MC, and the only explanation I can come up with is the convective phase of the CCKW, which is heading towards the IO currently, is projecting onto the RMM forecast while the MJO loses its OLR in the Western Hemisphere, leaving the strongest OLR signal over the MC region down the road.

MJO activity is still fairly weak in December as a whole, but increases from here on out through the winter. Our next time frame for coldost likely won't be until a new MJO wave develops and shifts over the IO/MC region.

Attached Files

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#90
Bryant

Posted 11 December 2014 - 03:52 PM

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The 3 contributors which make up the RMM index's aren't lined up currently = Muddled MJO signal. Notice the upper level winds (u200) which still has a great handle on the current MJO wave. OLR signal dies easily, but upper level winds remain

Attached Files



#91
primetime

Posted 11 December 2014 - 07:31 PM

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The 3 contributors which make up the RMM index's aren't lined up currently = Muddled MJO signal. Notice the upper level winds (u200) which still has a great handle on the current MJO wave. OLR signal dies easily, but upper level winds remain

 

bigmack - Is there a site where we can see these images updated, or is this a one time image?  Thanks



#92
Bryant

Posted 11 December 2014 - 08:04 PM

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bigmack - Is there a site where we can see these images updated, or is this a one time image? Thanks


http://monitor.cicsn...jo/current/rmm/

Scroll down to "RMM by variable"

#93
snow_wizard

Posted 11 December 2014 - 11:35 PM

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http://monitor.cicsn...jo/current/rmm/

Scroll down to "RMM by variable"

 

Fantastic stuff!  Now I get it.

 

It is kind of interesting how the OLR has not been on board for this El Nino at all.  From what I understand a warm ENSO event should have enhanced convection over the ENSO regions thus suppressing the OLR.  The enhanced convection is what usually fooks up our weather pattern in a Nino winter.  This season the OLR has not been suppressed.


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#94
Phil

Posted 12 December 2014 - 12:32 AM

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Weirdest Niño ever? Could be a candidate..Hadley Cells/H-WIR screams Niño, but the convective scheme is really lacking..and that's kind of the crux of ENSO feedback, so...yeah.

This could possibly be due to:

1) Off-Equator convective interference
2) IO buoyancy/convection (anti-nino)
3) CCKW interference (degradation of coherence)
4) Shallow WPAC H/C tower

What's the culprit? Most likely the -QBO forcing on Rossby Wave amplitude/lapse rates within the upper convective sigmas: http://journals.amet...ournalCode=atsc
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Cold season 2017/18:
Snowfall: 0"
Largest snowfall: 0"
Number of winter events: 0
Coldest High 67*F
Coldest low: 44*F
Highest sustained wind: 17mph
Highest wind gust: 26mph

#95
primetime

Posted 12 December 2014 - 05:31 AM

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http://monitor.cicsn...jo/current/rmm/

Scroll down to "RMM by variable"

 

Appreciate it...thanks



#96
snow_wizard

Posted 13 December 2014 - 09:13 AM

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How bizarre to have such full blown Ninoesque weather patterns while the tropical Pacific OLR is full blown Ninaish.  The strong positive OLR anom centered around 180 would do any Nina proud.

 

olra_c.gif


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#97
snow_wizard

Posted 13 December 2014 - 12:01 PM

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Models are really beginning to converge on another major MJO wave emerging later in the month.  Should be in excellent position for us by New Years or so.


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#98
Bryant

Posted 14 December 2014 - 11:28 AM

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Models are really beginning to converge on another major MJO wave emerging later in the month. Should be in excellent position for us by New Years or so.


I'm really curious to see where this goes. The "major MJO wave" you see is actually due to the real MJO wave weakening over the Western Hemisphere and a Kelvin Wave pushing towards the Eastern Hemisphere. The KW is projecting onto the RMM index as an MJO wave, but may have similar implications in the end. This is new to me honestly

#99
Bryant

Posted 16 December 2014 - 05:06 PM

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Changed the title of this thread because I want to start looking at other factors besides tropical forcing for LR forecasts. A few posters on the Accuwx forums are big on using the BSR/TR for their forecasts, and tend to do quite well. The following image shows a strong ULL over the Sea of Okhotsk which is to the west of the Bering Sea. It's said that what happens in the Bering Sea, will correlate to the Eastern US ~18-22 days later. Using that info, we can take locations to the west of the Bering Sea, and correlate them to the west. The Sea of Okhotsk would correlate to the west in general. In the image, you'll not only notice the ULL over the said location, but you'll also notice heights rising into the Bering Sea, which would be indicative of a cold west/ warm east scenario. The image is from the 21st of this month + 20 days = 10th January. Let's see how it plays out. 

 

egJIPqF.jpg



#100
Phil

Posted 16 December 2014 - 05:57 PM

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I don't see a cold west/warm east pattern at all, honestly. I believe the progression going forward favors a -EPO/-NAO during the 1st half of January, followed by a transition to a +PNA during the 2nd half of January, which will confine most of the colder anomalies to locations east of the Mississippi River.

The PV also looks to put up quite a fight as the SSW will start with a wave-1 response..so it might take until mid-January to take it down given the barotropic initialization allows elasticity to make a play at structural retention..so, yeah, need to watch that..
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Cold season 2017/18:
Snowfall: 0"
Largest snowfall: 0"
Number of winter events: 0
Coldest High 67*F
Coldest low: 44*F
Highest sustained wind: 17mph
Highest wind gust: 26mph