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My forecast for winter 2014-15


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Mid November 1958 actually had a pretty good cold airmass. Hate to be the bearer of such bad, 56 year old news....

 

Stopped raining here for 2 days in November of 1958... we are going to be running 13 out of 14 sunny days this time around.   No comparison.   

 

I know there were some brief interludes of cold in 1958-59... but for my location this current period of blocking will have provided more dry days than we saw for almost the entire November - April period that year.

 

Just checked... the Snoqualmie Falls station had 13 days without rain TOTAL from October 31, 1958 - April 8, 1959.

 

We will have 13 dry days already just in this blocking period alone!     

**REPORTED CONDITIONS AND ANOMALIES ARE NOT MEANT TO IMPLY ANYTHING ON A REGIONAL LEVEL UNLESS SPECIFICALLY STATED**

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Move if this in the wrong thread. Thx in advance.   Basic idea is, whether or not we actually see a Niño per CPC definition, the atmosphere is behaving as if we were in one (weak/unstable Walker Cell,

Looks pretty good. I have also been looking hard at 1958 and 2003 and to a lesser extent 1979. No question the strongest indication for any cold weather in the NW is in December or early to mid Jan.  

I think the main problem is we have been stuck in the same pattern for an eternity now. It has been very warm to hot almost continuously since the 4th of July weekend here in Socal with the exception

The solar factor is starting to weigh on 1958-59, as far as the NAM & Stratosphere are concerned. Definitely think 2014-15 will feature more high latitude blocking (relatively speaking).

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The solar factor is starting to weigh on 1958-59, as far as the NAM & Stratosphere are concerned. Definitely think 2014-15 will feature more high latitude blocking (relatively speaking).

 

Is the lower solar activity as of late having an effect on the winter outlook?

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Is the lower solar activity as of late having an effect on the winter outlook?

If it continues, then yes, there will be implications down the road (February/March). What's most important, forcing wise, is overall activity on a 2-3 month resolution, as the geoeffective background state of the upper atmosphere takes a bit longer to respond. Low solar activity reduces the geoeffective background state above 50mb, which reduces the O^3 photodissociation rate and thermal gradient, which amplifies the BDC/Surf-Zone aggregate, amplifying the MJO amplitude and weakening the PV leading to increased high-latitude blocking.

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Don't see any reason to make changes, except slight tweaks in timing:

 

December 1st to December 15th: Looks like a -EPF/-AMMI as tropical forcing progresses..generally +EPO/+NAO leading to a somewhat classic Niño signature over the U.S. with warmth centered over the Midwest.

 

December 15th to January 5th: Dynamically, should be the most exciting part of the winter season...tropical forcing boon in the WPAC will start another breaker train as a +EPF develops..major SSW/TAM collapse occurs between December 25 -January 5. Major cold over the lower-48...possibly a coast to coast icebox.

 

Here was my original forecast..basically the same:

 

November 15 - December 25th, +/- 10 days at end of interval: Ridge breaks into Alaska sometime in mid/late November, which will re-introduce polar air into the lower-48, at least for a time. However, poleward AAM propagation & biased MJO/tropical forcing (Beefy EPAC Hadley Cell) suggests that bouts of classic Nino (+AAM, NPAC-troughing, central US warmth) may pop up through December. Stationary waves/eddy flux will amplify, however, and begin to bombard the PV towards the Holiday Season.

 

December 25th - January 30th, +/- 15 days at end of interval: Cyclonic Wave breaking, Nino/-QBO forced BDC/Shear will likely force a heavy SSW event within 15 days of the Holiday season. This is when we'll see the true -AO regime take over, and legitimate Arctic air enter the country. This is also the best chance for the PNW to take part in an Arctic blast...during th initial stages of the regime shift. A major MJO wave will probably erupt in response to the SSW collapsing the TAM and cooling the equatorial upper troposohere/lower stratosphere. This will also mark the end of the crazy, tropically-governed NPAC/Western North American ridge regime that has dominated since January of 2013. Though ridging may persist in the West for a bit longer in the means, its "funding source" will be cut.

 

January 30th - February 28th, +/- 20 days at end of interval: Given the nature -QBO, strong BDC, & Niño-esque tropical forcing, I also favor a -AO/+PNA during this time, with a strong Aleutian low still possible. Generally cooler than normal over the Eastern US, while the rest of the nation will be dependent on the location of the NPAC low & the location of the PVA-appendage.

 

I might update this if something new flares up. Hope I do okay.

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[Are] .. We getting near to when this more initial scenario here above is supposed to start playing out, then. ?
 
.. Or what. ?

[That's a] Pretty broad, spread of days that you're looking at there. November 15th, to December 25th, Nov. 15th to 30th 15, plus 25 more 40. Then 10 more at either end. That's 60. Pretty much two full months, of 30 days. If I'm counting correctly. / ... Nov. 5th, to Jan. 4th of next year. Or am I missing something. ?  (edited  subsequently. ... Nov. to Dec. 15, plus only 10 days more. .. Or minus. only "40 days". Or "20".)
 
[A ...] Ridge breaks into Alaska sometime in mid/late November, which will re-introduce (?) polar air into the lower-48, at least for a time
 
 So like the 26th +/- 5 days. (?) And, for whatever time. The latter, the result of the former, occurring presumably, more or less synonymous with it, or at some point fairly near to shortly thereafter. And if with then, all of the other elements of your broader forecast for the period occurring at some point between then and some time in December. Correct. ?

 

.. However, poleward AAM propagation & biased MJO/tropical forcing (Beefy EPAC Hadley Cell) suggests that bouts (?) of classic Nino (+AAM, NPAC-troughing, central US warmth) may pop up through December. Stationary waves/eddy flux will amplify, however, and begin to bombard the PV towards the Holiday Season.

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[Are] .. We getting near to when this more initial scenario here above is supposed to start playing out, then. ?

 

.. Or what. ?

Yes, but the first half of December looks fairly zonal to me, with a tendency towards a +EPO (mostly GOA/NPAC troughing). Right now we have tropical forcing coming out of the IO, however this will slowly progress eastward into the WPAC. When accounting for the QBO's influence on the critical fields, the WPAC forced boost in meridional mass transport should pull the GOA trough westward by early or mid December, once again, towards the Aleutians. This is an optimal regime for stratospheric perturbation..we should see the surf zone amplify greatly, again, as cyclonic breakers bombard the PV...only now we'll have a more mature wave-field to deal with. I suspect a major SSW will occur in late December or early January..and I also suspect that it'll be a big one..

 

—[/font] [That's a] Pretty broad, spread of days that you're looking at there. November 15th, to December 25th, Nov. 15th to 30th 15, plus 25 more 40. Then 10 more at either end. That's 60. Pretty much two full months, of 30 days. If I'm counting correctly. / ... Nov. 5th, to Jan. 4th of next year. Or am I missing something. ?

Where are you seeing a 60 day spread?

 

Making deterministic predictions on the sub-seasonal level gets exponentially more difficult with time. Solely statistical methods don't suffer from this degradation, but they're indirect and often bust on the finer timescales..

 

I'll know a lot more about the 2nd half of winter after the SSW cycle completes..what goes down during that process is very important, and often throws both models and forecasters for a major loop..

 

[A ...] Ridge breaks into Alaska sometime in mid/late November, which will re-introduce (?) polar air into the lower-48, at least for a time.

 

So like the 26th +/- 5 days. (?) And, for whatever time. The latter, the result of the former, occurring presumably, more or less synonymous with it, or at some point fairly near to shortly thereafter. And if with then, all of the other elements of your broader forecast for the period occurring at some point between then and some time in December. Correct. ?

I'm not understanding this...I thought the dating was fairly straightforward...? I gave myself wiggle room because I wasn't sure exactly when the event would occur..I'm not a psychic...or at least I don't think I am..

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Yes, but the first half of December looks fairly zonal to me, with a tendency towards a +EPO (mostly GOA/NPAC troughing).

So "Yes", .. as to the element of your projected scenario's, timeframe's, "interval's", playing out, .. through to, "the first half of December". [This, although / however], where and when things, main and broader pattern wise (presumably.) "look, fairly zonal (if/ together) with a tendency toward a (more/ less) positive Eastern Pacific Oscillation ([lending/ contributing to a] mostly Gulf of Alaskan/ Northern Pacific [focused, more] troughing [type of regime/ set up. ?]

 

Is this all, about right. ?  /  The parantheticals that I've inserted here above, if not clear, being points possible more only, and that I'm not exactly clear on with the more truncated form that you've used where considering what you've said.

 

Where are you seeing a 60 day spread?

With your truncation of the idea "+/- 10 at end of interval", attached at the end, of each, interval (basic timeframe.) that you've pointed to, I guess I'd had a tendency, where having read through it, to attach 10 days to each end, of each of those intervals.

 

So … November 15th, to December 25th, Nov. 15th to 30th ..15 days, .. plus 25 more 40. Then 10 more  days, at .. the one end, more only. .. 50 days, more only. Is this correct then. ?

 

This with, and if of more incidental note here, as an more immediate response and preface to what I've asked / pointed to move above regarding the general timeframe more specific here, .. You might, with your having checked the accounting that I'd in fact included as part of my appreciation of it (above.), merely pointed to this discrepancy, more yourself. (If, and again, as a more general thought. Perhaps with expecting that what you post, is appreciable to others, you might want to think in terms more, of working better to appreciate what they say, to you.) .. Otherwise, my own advice to you where working to convey some of the ideas that you have here more broadly, would be to "veer" away from working to do so more casually. 

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So "Yes", .. as to the element of your projected scenario, timeframe, "interval" .. through to, "the first half of December". [This, although / however], where and when things, main and broader pattern wise (presumably.) "look, fairly zonal (if/ together) with a tendency toward a (more/ less) positive Eastern Pacific Oscillation ([lending/ contributing to a] mostly Gulf of Alaskan/ Northern Pacific [focused, more] troughing [type of regime/ set up. ?]

 

Is this all, about right. ? / The parantheticals that I've inserted here above, if not clear, being points possible more only, and that I'm not exactly clear on with the more truncated form that you've used where considering what you've said.

Yes, that's pretty much what I'm saying.

 

 

With your truncation of the idea "+/- 10 at end of interval", attached at the end, of each, interval (basic timeframe.) that you've pointed to, I guess I'd had a tendency, where having read through it, to attach 10 days to each end, of each of those intervals.

 

So … November 15th, to December 25th, Nov. 15th to 30th ..15 day, plus 25 more 40. Then 10 more days, at .. the one end, more only. .. 50 days, more only. Is this correct then. ?

 

This with, and if of more incidental note here, as an more immediate response and preface to what I've asked / pointed to above regarding the general timeframe more specific here, .. You might, with your having checked the accounting that I'd in fact included as part of my appreciation of it (above.), merely pointed to this discrepancy, more yourself. (If, and again, as a more general thought. Perhaps with expecting that what you post, is appreciable to others, you might think in terms more, of working better to appreciate what they say, to you.)

So, why are you adding up the error bars? One does not carry over to the next.

 

I appriciate and take into account any criticism Iget..it's healthy. I'm sorry if my dates are too broad..

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.. What's an "error bar". ?
 
.. And I'm not following the context here with what you've attached to this idea. 
 
"One" what, "doesn't carry over to" what other, "next". ?
 
edit: .. Oh. Now I think .. I'm getting what you've asked. ....
 
I've added, 10 days, to the "end" of .. the more initial timeframe that you've identified. .. 30 days, Nov. to Dec. 15, plus only 10 more. .. Or minus. .But this, is of course (ultimately. ?) only "40 days". Or "20". With my apologies. (Again, with, the truncation, these "little" elements, can be confusing, if only in my own view.)  > @
 
This with otherwise, where regarding your response to what I'd suggested more as having been what you'd said where looking at this period, ..... initially just above, more today.
 
"Pretty much". ... ?  
 
With this, could you perhaps additionally here, provide a little bit more clarity regarding, some at least, of the ideas that I'd suggestedmore in particularly where having doneas "possible points" more "only", i.e. estimations on my part, above. ? - http://theweatherfor...014-15/?p=45046
 
This with perhaps, to make this idea less involving for you, your perhaps merely emboldening, the more main and correct ideas, of and where looking at the in most cases dual options that I've inserted more parenthetically where in fact more unsure, with what I'd written. .As in, for example, here following.  (if/ together) (more/ less)

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If still confusing. .. Addressed (even clarified, hopefully.) within my post just above.  (I'd edited the idea in, not having noted that you'd responded further.)
 
And with this, I've also tacked in some additional ideas to that post.
 
These ideas with then and if more "zoom", back to my main focus (edited somewhat at this point.) where considering your view of where we are more currently, both relative to and where looking at your more initial timeframe pointed to, part of your broader and more extensive winter forecast, and your response to it: .. of course there's still more to this exchange, possible. - http://theweatherfor...014-15/?p=44402

 

[A ...] Ridge breaks into Alaska sometime in mid/late November, which will re-introduce (?) polar air into the lower-48, at least for a time
 
 So like the 26th +/- 5 days. (?) And, for whatever time. The latter, the result of the former, occurring presumably, more or less synonymous with it, or at some point fairly near to shortly thereafter. And if with then, all of the other elements of your broader forecast for the period occurring at some point between then and some time in December. Correct. ?


You'd said that you'd been unclear with respect to my impressions here, more where looking at what you've forecasted; more here above, part of that more initial Nov. to Dec 15 (plus or minus.) timeframe.
 

I'm not understanding this...I thought the dating [.....] was fairly straightforward...? I gave myself wiggle room [.....] because I wasn't sure exactly when the event would occur..[.....]


.. So "mid-late November", specific enough. This, with otherwise, I'm estimating, perhaps that you've been confused additionally, by my "And, for whatever time." suggestion above. Contextually, along the idea having been if only suggested more with its main connecting point embolded, with this idea I've meant to have pointed to your not having better pointed to just how long at all, the "re-introduction of polar air into the lower 48", might be either whether ongoing or maintained. .. And so with this, per your forecast, we can expect this (all, or some of it. ?) to occur fairly soon. ? .. Or perhaps no, with the way things are looking more at this point. ?
 
Those "other elements"from what I've asked here quoted more just abovepointed to by you, copied in here just below again, for general reference sake more quick. .. The question mark, highlighted inserted parenthetically, following the term "bouts", here below, being my own.
 
"... However, poleward AAM propagation & biased MJO/tropical forcing (Beefy EPAC Hadley Cell) suggests that bouts (?) of classic Nino (+AAM, NPAC-troughing, central US warmth) may pop up through December. Stationary waves/eddy flux will amplify, however, and begin to bombard the PV towards the Holiday Season."

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Don't see any reason to make changes, except slight tweaks in timing:

 

December 1st to December 15th: Looks like a -EPF/-AMMI as tropical forcing progresses..generally +EPO/+NAO leading to a somewhat classic Niño signature over the U.S. with warmth centered over the Midwest.

 

December 15th to January 5th: Dynamically, should be the most exciting part of the winter season...tropical forcing boon in the WPAC will start another breaker train as a +EPF develops..major SSW/TAM collapse occurs between December 25 -January 5. Major cold over the lower-48...possibly a coast to coast icebox.

 

Thanks for the updates Phil.  Always enjoy reading your upcoming pattern thoughts.  Solar Flux has been elevated of late....any concerns there?

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.. If a may make a comment regarding the post here just above, and its basic idea.

 

Logical (sort of I suppose.) that you'd be laying in "adjusted" forecasts relative to what you'd forecasted originally above, even with your having called that forecast your "Winter Forecast" here within this thread I guess. Probably best to work to differentiate the one idea (the original.) from the other (whatever, "updates" or even where looked at as "adjustments" to it.) fairly clearly, where considering the potential for confusion.  ... Again, just a more general comment. 

 

.. In the case that you may have perhaps missed this, otherwise. - http://theweatherforums.com/index.php/topic/644-my-forecast-for-winter-2014-15/?p=45078 

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Thanks for the updates Phil. Always enjoy reading your upcoming pattern thoughts. Solar Flux has been elevated of late....any concerns there?

Much appriciated. I suspect we're okay based on the modest geoeffective background state..if we spike further, there may be consequences come Feb/Mar...

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.. If a may make a comment regarding the post here just above, and its basic idea.

 

Logical (sort of I suppose.) that you'd be laying in "adjusted" forecasts relative to what you'd forecasted originally above, even with your having called that forecast your "Winter Forecast" here within this thread I guess. Probably best to work to differentiate the one idea (the original.) from the other (whatever, "updates" or even where looked at as "adjustments" to it.) fairly clearly, where considering the potential for confusion. ... Again, just a more general comment.

 

.. In the case that you may have perhaps missed this, otherwise. - http://theweatherforums.com/index.php/topic/644-my-forecast-for-winter-2014-15/?p=45078

I haven't made any significant changes to my forecast, thanks. If/when I do, I'll make sure to highlight that fact.

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.. From post 58 above, .. More basically I'm looking at and asking about, …. the idea of a .. "Ridge" being set (as it were.) to "break .. into Alaska", at about this point or one sometime over the next week or so. This idea, being essentially the main beginning point or element of your forecast's starting to play outmore ideally. 
 
.. And then with this, otherwise additionally, and with just more or less putting the idea more in the form a question heremain reference, also post no. 58 aboveagain, also more basically, .. if you still see " .. all of the "other elements of your broader forecast" for this more initial period pointed to [with it], "occurring" / playing out .. "at some point between [now] and some time in December."

 

Those "other elements" being, repeated here again for general reference more quick. 

 

.. However, poleward AAM propagation & biased MJO/tropical forcing (Beefy EPAC Hadley Cell) suggests that bouts (?) of classic Nino (+AAM, NPAC-troughing, central US warmth) may pop up through December. Stationary waves/eddy flux will amplify, however, and begin to bombard the PV towards the Holiday Season.

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.. From post 58 above, .. More basically I'm looking at and asking about, …. the idea of a .. "Ridge" being set (as it were.) to "break .. into Alaska", at about this point or one sometime over the next week or so. This idea, being essentially the main beginning point or element of your forecast's starting to play outmore ideally.

This event already occurred and is still ongoing, resulting in record breaking temperatures over much of the US, and another brush with Arctic air in the PNW..

 

.. And then with this, otherwise additionally, and with just more or less putting the idea more in the form a question heremain reference, also post no. 58 aboveagain, also more basically, .. if you still see " .. all of the "other elements of your broader forecast" for this more initial period pointed to [with it], "occurring" / playing out .. "at some point between [now] and some time in December.".

 

Those "other elements" being, repeated here again for general reference more quick.

 

.. However, poleward AAM propagation & biased MJO/tropical forcing (Beefy EPAC Hadley Cell) suggests that bouts (?) of classic Nino (+AAM, NPAC-troughing, central US warmth) may pop up through December. Stationary waves/eddy flux will amplify, however, and begin to bombard the PV towards the Holiday Season.

Yes, I do see this playing out...we should transition into a "classic" El Niño pattern during the first 2-3 weeks of December, with a GOA trough, +NAO, & warmth centered over the Northern Plains/Midwest. During the middle/later portion of December, I suspect we will move into a +PNA/-EPO pattern once again, with a SSW following soon after..

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This event already occurred and is still ongoing, resulting in record breaking temperatures over much of the US, and another brush with Arctic air in the PNW..

 

.. Hmm. "Ridge, breaking into Alaska." ... I'd had a different picture in mind where and with having read this. 

 

And, with the attachment to it more, "... sometime in mid/late November, which will re-introduce polar air into the lower-48, at least for a time." more or less synonymous .. to be clear here, .. apparently then, being more connected to what you've pointed to here above as having brought about the "record breaking temperatures over much of the U.S."..." along with additional "brush with Arctic air in the PNW".. Is this correct. ?

 

.. Apart from more currently, and still ongoing, what dates are you looking at / referring to more specifically here. ?

 

And noted, regarding what you've responded with otherwise here, above. Again, I'm merely working to follow your forecast.

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.. Hmm. "Ridge, breaking into Alaska." ... I'd had a different picture in mind where and with having read this.

 

And, with the attachment it to more, "... sometime in mid/late November, which will re-introduce polar air into the lower-48, at least for a time." .. to be clear here, .. being more what you're referring to as having occurred more or less synonymous, having brought about the "record breaking temperatures over much of the U.S."..." along with additional "brush with Arctic air in the PNW" .. that you've pointed to here above apparently.

 

.. Apart from more currently, and still ongoing, .. what dates are you looking at and referring to more specifically here. ?

The initial wave breaking event occurred at the beginning of the 2nd week of the month (November). The transition to a more zonal, Niño-like regime will occur during the 1st week of December, and persist until the 15th-20th, when a more amplified +PNA/-EPO regime should set up..

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The initial wave breaking event occurred at the beginning of the 2nd week of the month (November). The transition to a more zonal, Niño-like regime will occur during the 1st week of December, and persist until the 15th-20th, when a more amplified +PNA/-EPO regime should set up..

 

This is already readily apparent on the models. I don't see what is so hard to understand about it. 

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Snowfall                                  Precip

2020-21: 0.5"                        2020-21: 27.38"

2019-20: 23.5"                   2019-20: 58.54"

2018-19: 63.5"                   2018-19: 66.33"

2017-18: 30.3"                   2017-18: 59.83"

2016-17: 49.2"                   2016-17: 97.58"

2015-16: 11.75"                 2015-16: 68.67"

2014-15: 3.5"
2013-14: 11.75"                  2013-14: 62.30
2012-13: 16.75"                 2012-13: 78.45  

2011-12: 98.5"                   2011-12: 92.67"

 

It's always sunny at Winters Hill! 

 

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.. So about here then. ?

 

http://www.proxigee.com/14110822152014312_nasa_glblir.jpg

Correct, breaker occurred between the 8th and the 10th, followed by large scale ridging afterwards..

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I'd followed this set up and occurrence fairly closely in fact, and hadn't associated it particularly with what you'd pointed to suggested within your forecast. Also, I guess I'm having a little bit of trouble with the more basic and truncated terminology that you've used surrounding the "Ridge" occurrence/ development, "brake" idea that you'd pointed to. @ / The idea that I'd mentioned above previously as having appreciated differently. This with my having pictured and watched for otherwise, what I'd thought that you'd suggested, with my having more expected to see a much more solid, more amplified and narrowed ridging, the result of some amount more (at least.) of actual pressure buildup, and with a more true ridge development being caused to "break into"as in more with its main peak or crest being caused to move oversome portion/s of Alaska. This idea set against a more" wave breaking" type of "event", type of idea. 
 
141108-141110 Goes-W IR  (3-hourly.)
141107-141110 Goes-W IR
 
A bit at least certainly, also somewhat outside of the main allowance factor or timeframe, that you've attached to the one more main that you'd identified. 
 
 This all, if with also certainly, a strong, influx of deeper and more primary cold from the north, can be shown to have begun following the occurrence that you've pointed to here.  Of course .. the main Buffalo, NY Lake-Effect, more epic accumulation of Snow event, preceded otherwise and also of course by the stronger influx of cold more directly south, further west. 

141110-141121 Goes-E IR
 
… Not a contest certainly, and if in more in-forum terms here, certainly a bold effort:  I don't know just exactly how I'd rate your success here, ultimately.

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I'd followed this set up and occurrence fairly closely in fact, and hadn't associated it particularly with what you'd pointed to suggested within your forecast.

Maybe I can help you here. What exactly are you looking at to determine this? Wave breaking through and above the tropopause is fairly easy to understand and very consequential, as modeling does not handle/incorporate it well downstream..and it clearly took place on a huge scale a few weeks ago. Hard part is forecasting the forcing(s) that will favor a productive circulatory regimen for such activity..

 

Here are two papers broadly overviewing the dynamics of wave breaking..both are good reads:

 

Thorncroft et al:

 

http://onlinelibrary.wiley.com/doi/10.1002/qj.49711950903/abstract

 

Emily Riley:

 

http://www.rsmas.miami.edu/users/isavelyev/GFD-2/Rossby%20waves.pdf

 

The best way to observe this behavior is through the tropopausal 310K, 330K, or 380K PT, which largely removes noise in the LW sequence:

 

http://www.atmos.washington.edu/~hakim/tropo/info.html

 

Also, I guess I'm having a little bit of trouble with the more basic and truncated terminology that you've used surrounding the "Ridge" occurrence/ development, "brake" idea that you'd pointed to. @ / The idea that I'd mentioned above previously as having appreciated differently. This with my having pictured and watched for otherwise, what I'd thought that you'd suggested, with my having more expected to see a much more solid, more amplified and narrowed ridging, the result of some amount more (at least.) of actual pressure buildup, and with a more true ridge development being caused to "break into"as in more with its main peak or crest being caused to move oversome portion/s of Alaska. This idea set against a more" wave breaking" type of "event", type of idea.

That's not exactly how the cause-effect relationship works. I'd recommend reading the Holton-Haines et al paper in this case:

 

http://onlinelibrary.wiley.com/doi/10.1029/95RG02097/abstract

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November 15 - December 25th, +/- 10 days at end of interval: Ridge breaks into Alaska sometime in mid/late November, which will re-introduce polar air into the lower-48, at least for a time. However, poleward AAM propagation/E-biased MJO/tropics forcing (Beefy EPAC Hadley Cell) suggests that bouts of classic Nino (+AAM, NPAC-troughing, central US warmth) may pop up through December. Stationary waves/eddy flux will amplify, however, and begin to bombard the PV towards the Holiday Season.

 

December looks like a typical Niño w/ warmth centered in the Northern Plains/Midwest

 

Just read back through the full thread.  Looks like you've done very well so far...way back in Oct you called for the north Pac troughing and central US focused Nino warmth for early-mid Dec that we are seeing on the model ensembles.

 

Any thoughts or concerns regarding the pattern transition for late Dec?

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Just read back through the full thread. Looks like you've done very well so far...way back in Oct you called for the north Pac troughing and central US focused Nino warmth for early-mid Dec that we are seeing on the model ensembles.

 

Any thoughts or concerns regarding the pattern transition for late Dec?

Thanks [knocks on wood]. No big changes in the general idea, but here's how it should go down:

 

1) First, the huge, sprawling GOA low will tighten/organize into a more classic +PNA by December 15-20th..so you'll see more legitimate western ridging by then, with weak/moderate troughing in the East/Southeast..

 

2) Wave-breaking will then be favored over the NAO domain, which will scour out the deep, full-column vorticity dominating there. Currently targeting a flip to a -NAO in late December, likely during the last week of the month. The same wave-dynamics responsible for the NAO flip will also begin to pound the PV, leading to a major SSW towards the end of December or early January.

 

3) Major SSW should propagate effectively through the wave-field under a favorable Eliassen Palm flux, aided by a favorable QBO and tropical forcing..this should tank the NAM (AO/NAO), dropping the USA into a deep freeze in January. Interesting thing is the favored MQI/MJO at the time will try to force a -PNA/-EPO while the stratosphere/low-freq inertial forcing will insist on a strong -AO/-NAO..so, there are strong suggestions that we'll finally experience the elusive -PNA/-EPO/-AO/-NAO for January..

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Thanks Phil for the detailed reply regarding what you see going forward. Keep us posted!

Ensembles are now seeing the "tightening" of the +PNA, as I alluded to in my last post. Typical Branstrator Wave..the NAO is really fighting hard, but eventually I think it will cave..

 

GEFS:

 

http://catchmypicture.com/f/yzJGaM/800.jpg

 

GGEM:

 

http://catchmypicture.com/f/fhaJBu/800.jpg

 

NAEFS:

 

http://catchmypicture.com/f/8t0AJh/800.jpg

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Major SSW now looks likely between December 25th and January 5th..

 

Going to be fun watching all that cold air slide east of the Rockies!

Snowfall                                  Precip

2020-21: 0.5"                        2020-21: 27.38"

2019-20: 23.5"                   2019-20: 58.54"

2018-19: 63.5"                   2018-19: 66.33"

2017-18: 30.3"                   2017-18: 59.83"

2016-17: 49.2"                   2016-17: 97.58"

2015-16: 11.75"                 2015-16: 68.67"

2014-15: 3.5"
2013-14: 11.75"                  2013-14: 62.30
2012-13: 16.75"                 2012-13: 78.45  

2011-12: 98.5"                   2011-12: 92.67"

 

It's always sunny at Winters Hill! 

 

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Going to be fun watching all that cold air slide east of the Rockies!

Whether or not that occurs will depend on when exactly the SSW occurs, and whether it's an initial wave-1 displacement event (delayed) or we see a wave-2 split early-on..my guess is we start out with wave-1 then transition into a wave-2 regime..

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Take a deep breath big guy.

 

Don't you have some twins to raise?

They will be here no later than January 2nd the doctor says!

  • Like 1

Snowfall                                  Precip

2020-21: 0.5"                        2020-21: 27.38"

2019-20: 23.5"                   2019-20: 58.54"

2018-19: 63.5"                   2018-19: 66.33"

2017-18: 30.3"                   2017-18: 59.83"

2016-17: 49.2"                   2016-17: 97.58"

2015-16: 11.75"                 2015-16: 68.67"

2014-15: 3.5"
2013-14: 11.75"                  2013-14: 62.30
2012-13: 16.75"                 2012-13: 78.45  

2011-12: 98.5"                   2011-12: 92.67"

 

It's always sunny at Winters Hill! 

 

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Well, the AO/NAO should plunge by early January following SSW..PNA retrograde afterwards? Could be a fun month!

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Update:

 

After the ice-box during the first 2-3 weeks of January, a Niño-ish NPAC pattern should return (Aleutian Low/+PNA) later in January. That said, I see more of a -AO and/or -NAO this go around..so should be somewhat colder in the Eastern US..though a lot will depend on how the SSW/PV breakdown goes..at least in my opinion.

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This might be the best winter forecast I've ever made..I can't find any real errors so far..hopefully I'm not jinxing it [knocks on wood]

 

My forecast:

 

 

November 15 - December 25th, +/- 10 days at end of interval: Ridge breaks into Alaska sometime in mid/late November, which will re-introduce polar air into the lower-48, at least for a time. However, poleward AAM propagation/E-biased MJO/tropical forcing (Beefy EPAC Hadley Cell) suggests that bouts of classic Nino (+AAM, NPAC-troughing, central US warmth) may pop up through December. Stationary waves/eddy flux will amplify, however, and begin to bombard the PV towards the Holiday Season.

 

December 25th - January 30th, +/- 15 days at end of interval: Cyclonic Wave breaking, Nino/-QBO forced BDC/Shear will likely force a heavy SSW event within 15 days of the Holiday season. This is when we'll see the true -AO regime take over, and legitimate Arctic air enter the country. This is also the best chance for the PNW to take part in an Arctic blast...during the initial stages of the regime shift. A major MJO wave will probably erupt in response to the SSW collapsing the TAM and cooling the equatorial upper troposohere/lower stratosphere. This will also mark the end of the crazy, tropically-governed NPAC/Western North American ridge regime that has dominated since January of 2013. Though ridging may persist in the West for a bit longer in the means, its "funding source" will be cut.

 

January 30th - February 28th, +/- 20 days at end of interval: Given the nature -QBO, strong BDC, & Niño-esque tropical forcing, I also favor a -AO/+PNA during this time, with a strong Aleutian low still possible. Generally cooler than normal over the Eastern US, while the rest of the nation will be dependent on the location of the NPAC low & the location of the PVA-appendage.

 

I might update this if something new flares up. Hope I do okay.

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  • 2 weeks later...

Well, the AO/NAO should plunge by early January following SSW..PNA retrograde afterwards? Could be a fun month!

 

Any sign of the SSW yet? Not looking like AO/NAO is going to plunge any time soon...AO looks to hover on both sides of neutral for the next 7-10 days at least, NAO is weakly negative now, but is forecast to go quite positive soon. But I know those things can change quickly following a SSW.

 

So far the EPO is running the show...does this affect the rest of your forecast, or do you think it's just a timing thing?

Low. Solar.

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Any sign of the SSW yet? Not looking like AO/NAO is going to plunge any time soon...AO looks to hover on both sides of neutral for the next 7-10 days at least, NAO is weakly negative now, but is forecast to go quite positive soon. But I know those things can change quickly following a SSW.

 

So far the EPO is running the show...does this affect the rest of your forecast, or do you think it's just a timing thing?

Not much to change.

 

They'll still go negative in Jan I think, PV is just taking a slightly longer to prime for SSW. Doesn't affect the forecast much because the forcings behind the current/upcoming stratwarm are driving the cold into the US as predicted..the blocking is just oriented differently (more like 1978-79, less like 1968-69?).

 

So, no worries.

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Ok, so to clarify: from what you said previously, my understanding was that the stratosphere would lead the way into the blocking pattern in January with a SSW. But what you actually meant was tropical forcing would lead the way, causing a wave response, leading to blocking which would eventually lead to a SSW and complete destruction of the PV?

Low. Solar.

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Ok, so to clarify: from what you said previously, my understanding was that the stratosphere would lead the way into the blocking pattern in January with a SSW. But what you actually meant was tropical forcing would lead the way, causing a wave response, leading to blocking which would eventually lead to a SSW and complete destruction of the PV?

Yes, essentially.

 

I said the catalysts behind the strat-response (e-hem tropical forcing retrograde under -QBO waveguide) would force a duel breaker regimen (-EPO), followed by a strong NAM drop as a result of the strat feedback, while the tropical forcings favored a PNA retrograde.

 

Stratwarm events are forced via wave-breaking..the manner of which is determined by the tropics and the antecedent flow aloft (QBO). The amplification into a SSW is a feedback response resulting from wave-deflection in a baroclinic PV.

 

This will lead to a -NAM:

 

http://catchmypicture.com/f/erZuN8/640.jpg

 

http://catchmypicture.com/f/esvXdr/640.jpg

 

http://catchmypicture.com/f/ajYpTk/640.jpg

 

I did not forecast a drop in the NAM to precede the NPAC/NATL breakers..that's impossible. I did not say the wave-2 strat response would force the PNA retrograde..

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