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MJO/LR Forecasting Thread


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#101
Bryant

Posted 16 December 2014 - 07:08 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..

 

Not saying it will happen, just looking at different techniques :)


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#102
Black Hole

Posted 17 December 2014 - 08:04 AM

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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

What do those indicies stand for? I am guessing the BSR is Bearing Sea something. Thanks and good info.


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


#103
Bryant

Posted 17 December 2014 - 04:52 PM

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What do those indicies stand for? I am guessing the BSR is Bearing Sea something. Thanks and good info.


You're correct. Bering Sea Rule. BSR is what happens in the Bering Sea will correlate to the CONUS 18-22 days later. The typhoon rule states that once a typhoon recurves, a trough hits the CONUS 6-10 days later. It's also said that often times pressure systems in Japan correlate to the CONUS 6-10 days later as well.

No denying the fact that the upcoming timeframe will resemble the mid November timeframe
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#104
snow_wizard

Posted 17 December 2014 - 08:16 PM

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No doubt the last MJO wave is officially dead now and even the U200 never made it into octant 8.  Totally bizarre to have an MJO wave more robust in Nina friendly territory than Nino friendly considering we have warm ENSO.


Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#105
westiztehbest

Posted 17 December 2014 - 10:57 PM

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Not saying it will happen, just looking at different techniques :)

 

Good stuff.  Obviously we saw what happened in November with the massive low in the Bering Sea.  Since the low described today is west...perhaps that will reflect in a slightly different outcome this time.  Will be interesting to see what pans out.



#106
Bryant

Posted 17 December 2014 - 11:41 PM

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Good stuff.  Obviously we saw what happened in November with the massive low in the Bering Sea.  Since the low described today is west...perhaps that will reflect in a slightly different outcome this time.  Will be interesting to see what pans out.

 

Appreciate it! The BSR seems to have a fairly high accuracy rate, just always been typically associated with the East. The guys over at Accuwx have been working hard at utilizing the BSR to the best of their abilities. Here is a US map overlayed on top of their corresponding locations in the Bering Sea. Quite interesting 

 

g34ujxD.png


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#107
Bryant

Posted 29 December 2014 - 11:05 PM

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Where to begin.... Going to cover the current state of the MJO, why I feel our chances are better in Jan vs this month, and why the MJO is cycling in a La Nina type pattern, referencing the Walker Cell and Pacific MJO disruption.

 

First off, the MJO is currently pushing through the eastern IO and towards the MC, which is beautifully shown in the visual below. Note the twin low pressure systems (LP/HP is mirrored south of the equator), which indicates the upward/convective phase of the MJO is directly to the east. A simplified version of the MJO is also posted below to help out visually

 

 6f12d46e5e4c13ef6df10dd12c933773.gif

 

kMWOdbi.jpg

 

The MJO once again is in a favorable location for PNW cold, but just because the door is open doesn't mean the cold will come in unfortunately. Granted, as I'm typing this, it's in the 20's, feels like the teen's, and a strong north wind is howling. Just because the models took away the blast we were hoping for, doesn't mean the MJO hasn't been a huge benefit so far this season in determining our windows of opportunity.

 

As we progress throughout winter, the MJO plays a more significant role in our weather as it truly "wakes up" in a sense. Not only does it's overall amplitude increase,  it's overall duration increases as well. Given this, I believe the next go around with the MJO should result in better potential for the PNW.  

 

p4lptQO.gif

 

 

 

As many have noticed, a reference has been brought up to the Nov cold snap. The progression actually has many similarities....

 

CsNH8B7.gif

 

zeYAc8p.gif

 

Looking at the top image, you'll notice that the areas of blue shading represent convection, while the areas of yellow shading represent suppression. The solid red lines are associated with the MJO wave, which you can easily spot out during the mid-late November time frame. I had to do some photoshop work, but I combined the 2014 OLR anomalies with the new 2015 forecast anomalies to demonstrate that the wave will be very similar to the previous one. The MJO as of late has been initiating just west of 90E, which is around the central Indian Ocean (phase 2/3), and have been weakening just west of the dateline (phase 6/7). The fact that the MJO hasn't been roaming around in the central Pacific and western Indian Ocean is the reason for the continued cold snaps we've seen lately. Phases 4-6 are considered La Nina phases, while 8-2 are considered El Nino phases, with phases 3/7 being transitional phases. When the MJO is centered over the MC, in an ideal situation, we see a -PNA/-EPO/+NAO pattern, which consists of a blocking ridge over the Pacific, trough over the west, and a ridge over the east. As the convection associated with the MJO propagates into the west Pacific, we see an extension of the jet occur, forcing the -PNA ridge over the west coast. This in turn creates a +EPO due to the formation of an Aleutian low, which creates the stormy and atmospheric river setups we've already experienced. These 2 polar opposite setups have been occurring much quicker this season due to the MJO only focusing its attention in phases 2/3-6/7. However, there are also other variables at play of course, which can alter the overall configuration. The +PDO also entices an extended jet due to the cool SST's over the western and central Pacific promoting low pressure development. 

 

With that said, the reasoning as to why the MJO has been cycling in a La Nina type circulation is due to a unique Walker Cell setup. The Walker Cell, or Walker Circulation, is a model of the air flow throughout the tropics. Typically during an El Nino, the relaxed trade winds allow warm water to travel eastward, which causes moist air to rise in the lower levels over the pacific creating upper level divergence. To the west and east of the upper level divergence, the air cools and dries, thus sinking back down to the lower levels. The low level westerlies beneath the sinking air over the Pacific continue to push water toward the upward phase of the WC (Walker Cell), creating a full circulation. La Nina conditions mean the warm pocket of water is located around Maritime Continent, with the upward phase of the WC also being located in the same area. I probably did a horrible job at explaining it in words, but a visual will help out. The whole reason the MJO is in a more La Nina circulation this season is due to the WC also resembling a La Nina circulation. The upper level divergence of the MJO is what is responsible for the thunderstorm activity it produces, and when the MJO propagates into upper level convergence, it weakens the MJO's structure, resulting in a break down. 

 

h1rQlx3.jpg

 

I'll post some final thoughts tomorrow.... time to get some sleep!

 

Final thoughts:

 

While we may not have scored quite as nicely as we would have liked this go around, I believe we have one more solid shot that will be as good as any, if not better. If tropical forcing continues on the path we've seen so far, this current wave should push over the Pacific and weaken/die around phase 6/7 during mid month. As the wave progresses east, we should see the PNA ridge shift over us (+PNA), the jet stream strengthen and extend, and the mean trough will shift over the east, resulting in a El Nino type pattern. Once a new wave fires up over the IO sometime around the second half of Jan (looks like the 15th-20th at this point), I'm expecting to see a gradual shift to La Nina conditions once again. Quick disclaimer... this could all change given a SSWE igniting a drastic change in the overall tropical forcing regime :)

 

Compliments of @webberweather...

US-Winter-Monthly-Temps-DJF-El-Nino-Plac


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#108
Front Ranger

Posted 29 December 2014 - 11:22 PM

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Great post, NBM. I've noticed people on a couple other forums commenting recently on how we've moved into more La Nina-like forcing in the tropics since the fall. Definitely good to see in a neutral/weak ENSO year. And like last winter, the -EPO tendencies seem very persistent.

 

I remain hopeful for you guys to score a good snowstorm/more cold air at some point this winter, hopefully this month.


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Cool anomalies soothe the soul.


#109
Phil

Posted 30 December 2014 - 07:46 AM

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Great post, appreciate the update.

Regarding your Walker Cell composites, I'd include a larger ENSO sample w/ a full DJF aggregate, rather than just December 2009 & December 2010. This is because Walker cell strength fluctuates on relatively short timescales due to internal factors, as well as on multi-year scales due to external factors, independent of ENSO forcing, which operates on a much lower frequency.

I mention this because, for example, December 2009 was more of a Niño/+Walker (strong) configuration..January 2010 flipped to more of a Niño/-Walker (weak) configuration. Also, it's important to note that the Walker Cell does not behave in the manner it did back in the 70s-90s era due to the poleward migration of the Hadley Cells (observed since the mid/late 1970s). So I'd only use years after 1998 in my aggregate.
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Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#110
primetime

Posted 30 December 2014 - 08:21 AM

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Excellent post newbigmack.  You do a good job of presenting your thoughts in a well thought out and organized manner.  Keep up the good work.  It's a shame that posts like this garner less attention than the run of the mill post on the 300 hour GFS.

 

The questions I would have are.....was there something during the fall that would have given us a clue that the walker cell behavior was going to be more nina-like for Dec?  And do we expect it to remain nina-like through the winter?


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#111
hcr32

Posted 30 December 2014 - 09:30 AM

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Another great post! Thanks newbigmack.


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#112
Front Ranger

Posted 30 December 2014 - 10:32 AM

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Great post, appreciate the update.

Regarding your Walker Cell composites, I'd include a larger ENSO sample w/ a full DJF aggregate, rather than just December 2009 & December 2010. This is because Walker cell strength fluctuates on relatively short timescales due to internal factors, as well as on multi-year scales due to external factors, independent of ENSO forcing, which operates on a much lower frequency.

I mention this because, for example, December 2009 was more of a Niño/+Walker (strong) configuration..January 2010 flipped to more of a Niño/-Walker (weak) configuration. Also, it's important to note that the Walker Cell does not behave in the manner it did back in the 70s-90s era due to the poleward migration of the Hadley Cells (observed since the mid/late 1970s). So I'd only use years after 1998 in my aggregate.

 

I think you mean Nina to Nino in 2009-10...but of course, that was a strong Nino year. 


Cool anomalies soothe the soul.


#113
Phil

Posted 30 December 2014 - 11:16 AM

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I think you mean Nina to Nino in 2009-10...but of course, that was a strong Nino year.


No, stronger Walker Cell in Dec '09, weaker in Jan '10.

DzsNwM.jpg

zCTea0.jpg
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Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#114
Bryant

Posted 30 December 2014 - 11:20 AM

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Great post, NBM. I've noticed people on a couple other forums commenting recently on how we've moved into more La Nina-like forcing in the tropics since the fall. Definitely good to see in a neutral/weak ENSO year. And like last winter, the -EPO tendencies seem very persistent.

 

I remain hopeful for you guys to score a good snowstorm/more cold air at some point this winter, hopefully this month.

 

Thanks for the kind words. -EPO has definitely been a theme this winter, don't see much reason for that to change at this point. 

 

 

Great post, appreciate the update.

Regarding your Walker Cell composites, I'd include a larger ENSO sample w/ a full DJF aggregate, rather than just December 2009 & December 2010. This is because Walker cell strength fluctuates on relatively short timescales due to internal factors, as well as on multi-year scales due to external factors, independent of ENSO forcing, which operates on a much lower frequency.

I mention this because, for example, December 2009 was more of a Niño/+Walker (strong) configuration..January 2010 flipped to more of a Niño/-Walker (weak) configuration. Also, it's important to note that the Walker Cell does not behave in the manner it did back in the 70s-90s era due to the poleward migration of the Hadley Cells (observed since the mid/late 1970s). So I'd only use years after 1998 in my aggregate.

 

The Walker Cell is still a totally new topic to me honestly. I still have plenty to learn, but figured I could use what I have learned to demonstrate the La Nina type tropical forcing we've seen thus far. Thanks for the info though, good to know for future reference :)

 

Excellent post newbigmack.  You do a good job of presenting your thoughts in a well thought out and organized manner.  Keep up the good work.  It's a shame that posts like this garner less attention than the run of the mill post on the 300 hour GFS.

 

The questions I would have are.....was there something during the fall that would have given us a clue that the walker cell behavior was going to be more nina-like for Dec?  And do we expect it to remain nina-like through the winter?

 

Thanks prime. I'm much more of a visual learner, so throwing pictures and illustrations together is something I enjoy, even if my post have more visuals than actual writing. As far as the walker cell behavior, one reason I've seen discussed is the warm pool in the IO. This warm pool helps to "pull" the WC further west than it would typically be located in an El Nino, which in the end, works out in our favor.

 

Another great post! Thanks newbigmack.

 

Much appreciated :)



#115
luvssnow_seattle

Posted 30 December 2014 - 12:00 PM

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Where to begin.... Going to cover the current state of the MJO, why I feel our chances are better in Jan vs this month, and why the MJO is cycling in a La Nina type pattern, referencing the Walker Cell and Pacific MJO disruption...

Excellent post and learned a lot from it. Most of it made sense but some I still have to re-read to grasp. Great analysis and look forward to how it all plays out. Again, thank you so much!!!! :)


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#116
Bryant

Posted 30 December 2014 - 04:50 PM

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I received a dusting (if you can even call it that) of snow at the end of last month, which was about 2 weeks after the initial blast of cold mid month. The models are starting to show signs of this quick hitting trough around the 8th/9th, and I see no reason to believe it won't verify based on the Typhoon Rule. It wasn't anything impressive the last go around, and I doubt it will be this time either, but at least it's something to watch. Not on my CPU right now, but if anyone would like to see what I mean by Typhoon Rule, I can post it a bit later on. Let me know :)
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#117
snow_wizard

Posted 30 December 2014 - 06:21 PM

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Some models including one GFS based model and the ECMWF suggest the current MJO wave will move very slowly and could be in region 5 for quite some time. A nice window of opportunity for us.

Death To Warm Anomalies!

 

Coldest low so far 2017-18 = 42 
 


#118
Bryant

Posted 30 December 2014 - 07:05 PM

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Some models including one GFS based model and the ECMWF suggest the current MJO wave will move very slowly and could be in region 5 for quite some time. A nice window of opportunity for us.


This event really looks to progress the same as mid-end of Nov. The comparisons above show exactly what I mean. I'll be posting some TR maps when I get home that I'm sure you'd find interesting.

#119
Phil

Posted 30 December 2014 - 07:27 PM

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Wouldn't surprise me if the MJO wave maintains itself through a full cycle this time..-QBO is still dominating the export field, but I suspect the SSW/BDC may allow the wave to break through the wall.
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#120
Black Hole

Posted 30 December 2014 - 10:48 PM

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So what's the outlook for the next few weeks now?


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


#121
Bryant

Posted 31 December 2014 - 10:01 AM

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So what's the outlook for the next few weeks now?

 

 

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

 

The above image, which I posted back on the 16th shows a low pressure system positioned close to where we'd like to see for a trough in the PNW. This was using the BSR, which correlates to the US 18-22 days later. Forecast was from the 21st+(18-22) days =  Jan 8th - 12th. We can now use the TR (Typhoon Rule) to help verify the BSR once we get closer. The BSR/TR are also able to help verify MJO based forecasts. Considering tropical forcing will shift to the West Pacific around the ~10th or soon after, our window is about over at that point in my opinion. There is a system on the 8th-9th that's worth watching, but after that, the PNA ridge will shift over the west, or just off the coast, while the mean trough position shifts to the east. As the MJO pushes further into the Pacific, the jet stream roars over the Pacific resulting in an Aleutian low, returning us to the stormy and atmospheric river setup we saw earlier this month. The current wave should die off around the dateline (phase 6/7), then return to the western Indian Ocean sometime around the 20th +/- a few days. This allows the Pacific jet to relax and a pattern reset to take place. Once we see the new wave push over the Maritime Continent, that's when our next chance will be. To give a time frame would probably be foolish of me due to extrapolating something that shouldn't be extrapolated in the first place, but I'd say keep an eye on early Feb for a return to cold and hopefully snow this time around. There has been lots of talk regarding a SSWE, which definitely plays a role on tropical forcing. I'm not knowledgeable of the subject however, so any interference by the SSWE could throw off this forecast greatly =P

 

 

Don't mind the big image... but I wanted to share because it's a great visual of the Typhoon Rule

 

0cL6Oru.gif



#122
ShawniganLake

Posted 31 December 2014 - 11:38 AM

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Awesome and interesting info here.  I sometimes forget to look over here, as I get hung up just reading the main thread. 


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#123
Bryant

Posted 05 January 2015 - 03:46 PM

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East coast based forums are speculating whether or not the MJO will propagate into phases 7/8/1 this go around, due to the fact that those are favorable phases for cold in their location. Based off previous events and current configurations, I believe that once again we'll see the current wave die around phases 6/7 and reemerge over the western IO shortly after mid month. In the following image, the upper level convergence is apparent, which is acting as a wall against the eastward propagating MJO. This convergence is directly associated with the La Nina'ish Walker Cell we've see this year so far, which shows no signs of letting up currently. 

 

EmIHdBL.gif



#124
Chris

Posted 05 January 2015 - 03:54 PM

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East coast based forums are speculating whether or not the MJO will propagate into phases 7/8/1 this go around, due to the fact that those are favorable phases for cold in their location. Based off previous events and current configurations, I believe that once again we'll see the current wave die around phases 6/7 and reemerge over the western IO shortly after mid month. In the following image, the upper level convergence is apparent, which is acting as a wall against the eastward propagating MJO. This convergence is directly associated with the La Nina'ish Walker Cell we've see this year so far, which shows no signs of letting up currently. 

 

EmIHdBL.gif

 

Would you elaborate on your chart? I'm not sure what its showing.  Does blue represent easterlies anomalies?



#125
Bryant

Posted 05 January 2015 - 04:02 PM

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Would you elaborate on your chart? I'm not sure what its showing.  Does blue represent easterlies anomalies?

Of course, sorry about that. The blue represents westerlies actually (divergence), which can be associated with a convective regime. The yellow represents easterlies (convergence), which is associated with a suppressed regime. The MJO is made up of divergence in the upper levels, which produces convective thunderstorms. As the wave propagates and runs into the upper level convergence, the environment is no longer supportive of thunderstorm/convective activity, which typically will significantly weaken the wave.


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#126
Phil

Posted 05 January 2015 - 07:28 PM

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You can thank the dominant -QBO/low relative HC intensity for the elongated Walker Cell variance. Problem is these regimes are tough to maintain..so any break in the mass transfer/export fields will remove most longitudinal inhibition.

I'll give the current MJO wave a 40% chance to break the barrier set by the QBO.
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#127
Phil

Posted 15 January 2015 - 01:18 AM

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You can thank the dominant -QBO/low relative HC intensity for the elongated Walker Cell variance. Problem is these regimes are tough to maintain..so any break in the mass transfer/export fields will remove most longitudinal inhibition.

I'll give the current MJO wave a 40% chance to break the barrier set by the QBO.


Man, this wave is trying hard to break through..EPF is going weakly poleward (strong eddy flux) w/ mt-progression now beginning..this was one of my worries..that the combination of a strong wave and changing export field may allow a fundamental shift in the tropical circulations..

Biggest +AAM response since summer/autumn of 2014..
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#128
Bryant

Posted 15 January 2015 - 10:42 PM

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If tropical forcing continues on the path we've seen so far, this current wave should push over the Pacific and weaken/die around phase 6/7 during mid month. As the wave progresses east, we should see the PNA ridge shift over us (+PNA), the jet stream strengthen and extend, and the mean trough will shift over the east, resulting in a El Nino type pattern. Once a new wave fires up over the IO sometime around the second half of Jan (looks like the 15th-20th at this point), I'm expecting to see a gradual shift to La Nina conditions once again. 

 

 

 

As the MJO pushes further into the Pacific, the jet stream roars over the Pacific resulting in an Aleutian low, returning us to the stormy and atmospheric river setup we saw earlier this month. The current wave should die off around the dateline (phase 6/7), then return to the western Indian Ocean sometime around the 20th +/- a few days. This allows the Pacific jet to relax and a pattern reset to take place. Once we see the new wave push over the Maritime Continent, that's when our next chance will be. To give a time frame would probably be foolish of me due to extrapolating something that shouldn't be extrapolated in the first place, but I'd say keep an eye on early Feb for a return to cold and hopefully snow this time around.

 

 

 

Not a bad call in my opinion. 

 

OlT2bOf.png



#129
Phil

Posted 16 January 2015 - 12:15 AM

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Very good call.

What's your take on the poleward-biased WPAC Hadley Cell screwing with mass transport E of the dateline? Literally a brick wall there..
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#130
Bryant

Posted 16 January 2015 - 02:04 AM

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Very good call.

What's your take on the poleward-biased WPAC Hadley Cell screwing with mass transport E of the dateline? Literally a brick wall there..

 

I know that the WC is definitely displaced this season and the upper lvl convergence hasn't allowed passage as of yet, don't really know if it will at all this winter. -NAO has been lacking, which in my opinion, directly correlates to the WC displacement, not allowing MJO to hang over the Pacific long enough to get the -NAO rolling. We see continued hits on the PV, but not much in the way of progress towards a significant SSWE, which also seems to correlate to the displaced WC. Honestly though, not very knowledgeable on the subject and I'm pretty much talking out of my a** :)



#131
Phil

Posted 16 January 2015 - 11:03 AM

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Lol, you're a lot smarter than you realize. You're above many pro mets, actually.
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Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#132
Bryant

Posted 16 January 2015 - 04:23 PM

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Lol, you're a lot smarter than you realize. You're above many pro mets, actually.

 

While I may not agree, I appreciate it :) 



#133
Phil

Posted 21 January 2015 - 07:23 PM

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Looks like the recent MJO forcing coupled with the WPAC Hadley Cell contraction/poleward AAM transport may prevent a significant tropical forcing excursion into the IO. Can throw seasonal wave forcing transition(s) under a -QBO into the mix. Going to be an interesting 10 days, I suspect.
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#134
Bryant

Posted 03 February 2015 - 01:12 AM

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Well, on the bright side, the MJO looks to become favorable for the west around the midway point of next month. Roundy plots show the MJO stalling out over the IO for a while before finally propagating across the MC. We'll see



Taking a look back at this call, it may end up coming to fruition if the typhoon rule continues to verify. Taking a look at Asia, we see a quick hitting low pressure system digging to the SE before being replaced by a ridge a few days later. What would this mean for us? Given the location of the system, if the correlation held true, we'd see a trough dig into the west around the 14th-16th. My only fear is the trough may be centered too far to the east for us to really benefit, leaving us in more of a NW flow rather than a N flow.

Rt3avMg.png


On that note... MJO is really stalling out this go around. We'll see if it ends up working out for us.

#135
Phil

Posted 03 February 2015 - 03:47 AM

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As it's been all winter, I think it's a battle between inertia/top-down forcing and tropical/bottom-up forcing. This winter, the former has been winning out, much like it did in 2013-14, which I did not really anticipate. The Greenland/Hudson Bay Vortex has become so entrenched in the flow field(s) that it is now the perturbative epicenter of the mid latitude mass transfer system. We've seen strong bouts of tropical forcing lead to large swings in the NPAC circulations, but the inertia contained within that vortex has allowed it to resist external forcing, with the aid of a very elastic stratospheric PV.

The key to breaking up the tropospheric vortex was the early January SSW..which ultimately failed..now that the PV and tropospheric vortex are constructively feeding back off one another, it's going to be very hard to get the pattern to change until Spring, or maybe even Summer.

Regarding the MJO, my fear was that we'd see this transition occur, where the IO is no longer favored for large scale convergence. That appears to be the case..I'd look towards region 6-7 for future initialiazation, if a new wave is to emerge.
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#136
Dan the Weatherman

Posted 03 February 2015 - 05:41 PM

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As it's been all winter, I think it's a battle between inertia/top-down forcing and tropical/bottom-up forcing. This winter, the former has been winning out, much like it did in 2013-14, which I did not really anticipate. The Greenland/Hudson Bay Vortex has become so entrenched in the flow field(s) that it is now the perturbative epicenter of the mid latitude mass transfer system. We've seen strong bouts of tropical forcing lead to large swings in the NPAC circulations, but the inertia contained within that vortex has allowed it to resist external forcing, with the aid of a very elastic stratospheric PV.

The key to breaking up the tropospheric vortex was the early January SSW..which ultimately failed..now that the PV and tropospheric vortex are constructively feeding back off one another, it's going to be very hard to get the pattern to change until Spring, or maybe even Summer.

Regarding the MJO, my fear was that we'd see this transition occur, where the IO is no longer favored for large scale convergence. That appears to be the case..I'd look towards region 6-7 for future initialiazation, if a new wave is to emerge.

Are we experiencing something unusual either with the solar activity or the atmosphere in recent years that is favoring this behavior of the Greenland / Hudson Bay vortex? I have never seen such persistence of this type of pattern before and it is leading to a potentially catastrophic drought situation in California. I am very eager for this pattern to change and I don't want to see any more repeats of either 2013-14 or 2014-15 for a very long time, if ever!



#137
Phil

Posted 03 February 2015 - 06:32 PM

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Can be blamed on the +Hadley/+Solar regime w/ low-freq IO forcing from September-present..that inertia is now hard to break as the strat-PV & Hudson Bay Vortex are now constructively feeding back off one another and overwhelming the tropical forcings.

If Sun hadn't dampened the efficiency of the +EPF/wave driving regimen, the tropical forcing/-QBO stress would have combined to force a SSW and enlarge the wave field, replacing the Hudson Bay Vortex with a deep -NAO..

Scary thing is, 2015-16 is setting up to be nearly a carbon copy of 2013-14, forcing wise. Could we go another year w/ this circulation? :lol:
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#138
Dan the Weatherman

Posted 03 February 2015 - 07:28 PM

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Can be blamed on the +Hadley/+Solar regime w/ low-freq IO forcing from September-present..that inertia is now hard to break as the strat-PV & Hudson Bay Vortex are now constructively feeding back off one another and overwhelming the tropical forcings.

If Sun hadn't dampened the efficiency of the +EPF/wave driving regimen, the tropical forcing/-QBO stress would have combined to force a SSW and enlarge the wave field, replacing the Hudson Bay Vortex with a deep -NAO..

Scary thing is, 2015-16 is setting up to be nearly a carbon copy of 2013-14, forcing wise. Could we go another year w/ this circulation? :lol:

I certainly hope not, as California will be in HUGE trouble! What will it take to break this circulation pattern, another SSW event at some point in the future or will we have to wait until the solar max starts to go toward minimum? California just hasn't experienced this degree of dryness in other solar maxes of the past, even though the late 80's and early 90's drought was near the max and quite dry at its peak, but not quite as severe as this drought has been.



#139
Bryant

Posted 10 September 2015 - 09:25 PM

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Hey everyone. This winter isn't looking good for snow lovers unfortunately, but I plan on starting this thread back up regardless. Hopefully I'll continue to learn and anyone else who'd like to learn can join in. I have a feeling the following will be a common occurrence this winter....

 

tV0W510.gif



#140
Phil

Posted 11 September 2015 - 12:46 AM

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2015-16 is setting up to be nearly a carbon copy of 2013-14, forcing wise. Could we go another year w/ this circulation?


This will probably be a bust.
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#141
Phil

Posted 11 September 2015 - 12:48 AM

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Hey everyone. This winter isn't looking good for snow lovers unfortunately, but I plan on starting this thread back up regardless. Hopefully I'll continue to learn and anyone else who'd like to learn can join in. I have a feeling the following will be a common occurrence this winter....

tV0W510.gif


Ah, the dreaded Alaskan low. The kiss of death to winter for everyone west of the Mississippi.
  • Bryant likes this
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#142
Bryant

Posted 11 September 2015 - 07:58 AM

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Ah, the dreaded Alaskan low. The kiss of death to winter for everyone west of the Mississippi.

 

Yes, not something we like to see. So close yet so far away. You in agreement with this at all? 



#143
Phil

Posted 11 September 2015 - 10:15 AM

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Yes, not something we like to see. So close yet so far away. You in agreement with this at all?


I'm definitely in agreement overall. I'm just trying to figure out where the low will set up. Key is the progression of the low frequency tropical forcing through the next 10-15 weeks. If the Alaskan low sets up far enough west (south of the Aleutians), it's possible you guys in the PNW can encounter Arctic air behind a wave breaker (November 2014 being an example of this).

Also, forcing from the MJO/higher frequency forcing & the stratosphere can overwhelm the Niño forcing anytime, so that's also something to watch, imo.
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F

#144
Chris

Posted 14 September 2015 - 07:44 AM

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Ah, the dreaded Alaskan low. The kiss of death to winter for everyone west of the Mississippi.

 

Not for the American southwest.



#145
Phil

Posted 14 September 2015 - 09:06 AM

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Not for the American southwest.


I think it depends on where the vortex is located. If it's up in Alaska, then everyone west the Mississippi (at least) roasts. If it's in the Southern Gulf of Alaska, that's another story.
Personal Weather Station, Live Stream on Wunderground: https://www.wundergr...BETHE62#history

Warm season 2017
Thunderstorm days: 10
Severe days: 5
Rain total: 11.58"
Highs at/above 90*F: 16
Warmest high: 99.4*F
Warmest low: 79.7*F