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Winter 2014-2015 Pattern Discussion Thread III


BIG FROSTY

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Can the day 10 cutter trend weaker and farther east like next Fridays storm has?

The day 10 bomb, is gonna be the pattern changer for the Fab Feb! Book it, I think it was 994 a couple of runs ago, has weakened slightly on subsequent runs, but when it shows a cutter at day 10, you can take it to the bank, southern snow or ice 3 days out, will never happen!
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 I just checked this. The 1/8-9/15 MJO was the strongest JAN MJO phase 5 on record (back to 1975) and only 2nd to 2/18-21/85 for the strongest phase 5 on record in any DJF. Despite that, 1/8-9/15 was a very cold period in the E US, which is quite interesting considering that phase 5 has been the warmest phase by far overall for at least much of the SE US.

 

http://cawcr.gov.au/staff/mwheeler/maproom/RMM/RMM1RMM2.74toRealtime.txt

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 I just checked this. The 1/8-9/15 MJO was the strongest JAN MJO phase 5 on record (back to 1975) and only 2nd to 2/18-21/85 for the strongest phase 5 on record in any DJF. Despite that, 1/8-9/15 was a very cold period in the E US, which is quite interesting considering that phase 5 has been the warmest phase by far overall for at least much of the SE US.

 

http://cawcr.gov.au/staff/mwheeler/maproom/RMM/RMM1RMM2.74toRealtime.txt

For lack of a better way of putting it, that info, along with how some other indices/teleconnections seem almost "backwards" this year compared to what one might actually expect they would lead to (e.g., the plethora of winter forecasts issued in late fall that basically busted based on a string of data that would have suggested a different set up than what we've seen), may explain why models have been so wonky, and from a gut level may mean the best way to look at what is down the pipeline is basically to go somewhat "opposite" of what the matrix of indices suggest.

 

No way to quantify this - but just thinking sitting here with a 102 flu....

 

(have mercy on me if this is a crazy thought, by the way!)

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Maybe the indices aren't really that strong as indicators. The details are too complicated to be captured by a numerical index derived from measure pressure in a handful of locations on the Earth. We want indices because they give us quick answers to a complex question. I fear the community makes a mistake by putting so much weight on them.

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Maybe the indices aren't really that strong as indicators. The details are too complicated to be captured by a numerical index derived from measure pressure in a handful of locations on the Earth. We want indices because they give us quick answers to a complex question. I fear the community makes a mistake by putting so much weight on them.

 

Widre,

  Good point. Some have stronger indications than others. However, I think they're still very good tools, especially when used together with other indices. I think that using them helps much more often than hurts. But they should be used as tools, not as crystal balls. IMO.

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Maybe the indices aren't really that strong as indicators. The details are too complicated to be captured by a numerical index derived from measure pressure in a handful of locations on the Earth. We want indices because they give us quick answers to a complex question. I fear the community makes a mistake by putting so much weight on them.

Unfortunately I agree with you. I remember Dec 10th the models and all the winter optimists were saying last week of Dec things would be better, well it took till Jan 5th to see cold and a terrible pattern for snow. Now it's Jan 11th and we are saying the same thing. I think it will be more like early to mid Feb, if we see a snow pattern at all this winter. What Jon posted above doesn't look that good until day 13+, it takes day 13+ looks 7-10 days to even get inside day 10 and it takes day 10 looks to get to day 1 probably 15 days. There is a reason the winter for entire east has sucked and a reason we have had no blocking.

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I kind of have mixed feelings about that. There is a reason that we root for certain configurations in the atmosphere. I mean, we can all agree that a big ridge in the west is preferable to a big trough there. The PNA helps to quantify that. So there is value in looking at cold and snowy patterns in the SE as they relate to the quantifiable indexes that have been constructed.

At the same time, a numerical value is not the be all end all, like has been pointed out. To me, it is ultimately less relevant than the pattern associated with it at the time...see the NAO for an example. There are different configurations in the atmosphere that yield a negative value, so to Widre's point, there's more to pay attention to than a number on a scale.

When I look at the 10 day ENS prog that shows the AO dropping to -4, I'd say there's a better correlation with eastern US cold than if it was headed to +4. So I think there's value there.

In the end, the idea that the atmosphere is more complex than a set of numerical values is quite correct. But, in similar fashion to analogs, index values can help to point us in a general direction, at least until other variables become more clearly defined.

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I say we TRUST what Eric, webber, has been posting.  FEB will be our month and thats IT!

 

Thanks Chris... :)

 

 

 I just checked this. The 1/8-9/15 MJO was the strongest JAN MJO phase 5 on record (back to 1975) and only 2nd to 2/18-21/85 for the strongest phase 5 on record in any DJF. Despite that, 1/8-9/15 was a very cold period in the E US, which is quite interesting considering that phase 5 has been the warmest phase by far overall for at least much of the SE US.

 

http://cawcr.gov.au/staff/mwheeler/maproom/RMM/RMM1RMM2.74toRealtime.txt

 

Indeed, I have this most recent MJO spike @ its climax in amplitude on the 9th of January ranked 134th out of about 15,000 days for highest MJO amplitude on record, or in the 99.1%tile...

 

In fact, the January 8th & 9th are ranked #1 & 2 for January MJO Phase 5...  & January 9th @ least in the preliminary numbers ranks as the 24th highest January Phase 5 MJO day on record, and the majority of the large amplitude days in front of it interestingly tend to occur near in the transition period between the southeastern Asia & Australian monsoon seasons. March, May, September, & October were popular months for extreme phase 5 MJO events, at a time when the convective signal associated w/ the MJO becomes approximately symmetric about the equator, which of course in the spring when the SST gradient is weakest across the Equatorial Pacific, allows for the MJO to excite near-equatorial oceanic Kelvin Waves that ultimately play a large role in determining the medium-long term fate of the ENSO index...

 

Even a MJO pulse w/ amplitude greater than 3 is fairly rare in of itself, and on average it only occurs about 1% of the time. Here are the relative frequencies (denoted by % of days) of the MJO at various amplitudes, greater than equal to the prescribed amplitude of course. The distribution of days seems to imply that the MJO amplitude frequency as a function of amplitude is somewhat Gaussian in nature, and based on the data I have shown below, the spectral peak is likely somewhere around the sigma 1.0 amplitude, i.e. the edge of the "Circle of Death"..

 

MJO Amplitude            % of days/probability of occurrence

>4.0 sigma amplitude                       .01%

>3.5 sigma amplitude                       .25%

>3.0 sigma amplitude                     1.09%

>2.5 sigma amplitude                     4.25%

>2.0 sigma amplitude                    13.20%

>1.5 sigma amplitude                    32.53%

>1.0 sigma amplitude                    60.79%

>0.5 sigma amplitude                    88.71%

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For lack of a better way of putting it, that info, along with how some other indices/teleconnections seem almost "backwards" this year compared to what one might actually expect they would lead to (e.g., the plethora of winter forecasts issued in late fall that basically busted based on a string of data that would have suggested a different set up than what we've seen), may explain why models have been so wonky, and from a gut level may mean the best way to look at what is down the pipeline is basically to go somewhat "opposite" of what the matrix of indices suggest.

 

No way to quantify this - but just thinking sitting here with a 102 flu....

 

(have mercy on me if this is a crazy thought, by the way!)

 

 Feel better soon! That is an interesting idea, but I don't think going opposite from this point is necessarily wise just because of how it has worked out to this point. IMO

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Unfortunately I agree with you. I remember Dec 10th the models and all the winter optimists were saying last week of Dec things would be better, well it took till Jan 5th to see cold and a terrible pattern for snow. Now it's Jan 11th and we are saying the same thing. I think it will be more like early to mid Feb, if we see a snow pattern at all this winter. What Jon posted above doesn't look that good until day 13+, it takes day 13+ looks 7-10 days to even get inside day 10 and it takes day 10 looks to get to day 1 probably 15 days. There is a reason the winter for entire east has sucked and a reason we have had no blocking.

 

 

As I mentioned a little earlier in this forum, w/ the core of the HLB in & around the high latitude North Pacific & Alaska (-WPO/-EPO), we're pretty much stuck w/ primarily CAD & Miller B threats until an appreciable amount of high-latitude blocking decides to show up over the North Atlantic & Greenland. However, this stout -EPO/WPO configuration is actually the norm for warm neutral/Weak El Nino Januarys...

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I kind of have mixed feelings about that. There is a reason that we root for certain configurations in the atmosphere. I mean, we can all agree that a big ridge in the west is preferable to a big trough there. The PNA helps to quantify that. So there is value in looking at cold and snowy patterns in the SE as they relate to the quantifiable indexes that have been constructed.

At the same time, a numerical value is not the be all end all, like has been pointed out. To me, it is ultimately less relevant than the pattern associated with it at the time...see the NAO for an example. There are different configurations in the atmosphere that yield a negative value, so to Widre's point, there's more to pay attention to than a number on a scale.

When I look at the 10 day ENS prog that shows the AO dropping to -4, I'd say there's a better correlation with eastern US cold than if it was headed to +4. So I think there's value there.

In the end, the idea that the atmosphere is more complex than a set of numerical values is quite correct. But, in similar fashion to analogs, index values can help to point us in a general direction, at least until other variables become more clearly defined.

 

+1

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 Feel better soon! that is an interesting idea, but I don't think going opposite from this point is necessarily wise just because of how it has worked out to this point. IMO

Thanks! I'm trying to feel better but according to the doc, it'll be at least Wed (even having had the super duper flu shot back in October). Like early season forecasts, the shot busted .... . Of well ....

 

Like I said - it was just a random thought - maybe not wise (and probably fever driven - but what else does a sick puppy weather lover have to do?), but when everything seems turned upside down, maybe you get a better perspective by standing on your head and looking at it in an upside manner.  It happens that way sometimes in court trying to get to the truth, so I thought, why not with weather ....

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Widre,

  Good point. Some have stronger indications than others. However, I think they're still very good tools, especially when used together with other indices. I think that using them helps much more often than hurts. But they should be used as tools, not as crystal balls. IMO.

The AO and NAO have been mostly positive since early December. Is it any coincidence that winter wx has been lacking? It is amazing how many folks have tried to justify the pattern getting cold with those indices staying positive. Can it happen? Sure, but rarely. The good thing? The AO, according to the CPC ensembles, could go negative later in the month. NAO...well.

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The was a big shift in one run. See if it holds tomorrow. Actually boots the Greenland low for a few days.

Pack, you have to love this run. Big -epo and higher heights spread all over the arctic and Greenland. Complete wholesale shift from where we've been for the last 6 weeks. And looks very similar to the gefs so their's some agreement at long leads. Storms aren't going to cut easily on that pattern. Overunning look verbatim but let's see where we are in a week. I'm cautiously optimistic that we are moving towards a pattern that can produce slower moving and bigger storms.

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Pack, you have to love this run. Big -epo and higher heights spread all over the arctic and Greenland. Complete wholesale shift from where we've been for the last 6 weeks. And looks very similar to the gefs so their's some agreement at long leads. Storms aren't going to cut easily on that pattern. Overunning look verbatim but let's see where we are in a week. I'm cautiously optimistic that we are moving towards a pattern that can produce slower moving and bigger storms.

And yet it still dumps the cold in central/west and torches the east through day 15. To believe it I am going to need too see the trough in the east with blocking :-)

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Maybe the indices aren't really that strong as indicators. The details are too complicated to be captured by a numerical index derived from measure pressure in a handful of locations on the Earth. We want indices because they give us quick answers to a complex question. I fear the community makes a mistake by putting so much weight on them.

 

I used to think this way as well, but I've since changed my line of rationale & am of the notion that it's up to weather enthusiasts & mets to not succumb to literal interpretation & box themselves in when looking at the various teleconnections. Sure looking at one or two likely doesn't tell you the entire story, but the reason they were made in the first place was to monitor the progression of semi-permanent/seasonal prominent atmospheric features & the spatial distribution of the patterns they're reflect onto (like a crash in geopotential heights that occurs in GOA w/ Pacific Jet extension, or the monitoring of the Icelandic low/Azores-Bermuda High as a localized response to the NAM/AO (i.e. the NAO) or the Scandinavian high, etc.) which in of themselves are too complex, intertwined & smeared by various external forcings, etc. for us to observe directly & impartially. Thus, looking at a multitude of indices across a much broader spectrum & their derivatives (change over specified intervals of time) is extremely useful...

 

I kind of have mixed feelings about that. There is a reason that we root for certain configurations in the atmosphere. I mean, we can all agree that a big ridge in the west is preferable to a big trough there. The PNA helps to quantify that. So there is value in looking at cold and snowy patterns in the SE as they relate to the quantifiable indexes that have been constructed.

At the same time, a numerical value is not the be all end all, like has been pointed out. To me, it is ultimately less relevant than the pattern associated with it at the time...see the NAO for an example. There are different configurations in the atmosphere that yield a negative value, so to Widre's point, there's more to pay attention to than a number on a scale.

When I look at the 10 day ENS prog that shows the AO dropping to -4, I'd say there's a better correlation with eastern US cold than if it was headed to +4. So I think there's value there.

In the end, the idea that the atmosphere is more complex than a set of numerical values is quite correct. But, in similar fashion to analogs, index values can help to point us in a general direction, at least until other variables become more clearly defined.

 

I would like to add in the fact that it's pretty hard to screw up February in an El Nino or +ENSO year for that matter & as I've shown w/ pervious posts the seasonal modulation of the NAM/AO by ENSO is quite evident in the data & you should quickly take note of how comparatively minuscule my sample size is for the +AO/+ENSO years (+AO/NAO El Nino/+ENSO Februarys are not too common, only occurring about 25% of the time). Also I find it interesting despite the larger discrepancy in sample size, the temperature distribution of the +AO & -AO El Ninos become increasingly similar in character as the winter progresses and -AO +ENSO winters generally tend to exhibit less monthly variance...

+AO/+ENSO Februarys are actually neutral-below normal in the east US. It's pretty hard to screw up February given the current setup, even if the AO somehow decides not to cooperate...

AO-DJF-US-temps-Warm-Neutral-Weak-El-Nin

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And yet it still dumps the cold in central/west and torches the east through day 15. To believe it I am going to need too see the trough in the east with blocking :-)

It's going to be a step down process, just like last cold shot. Starts out west and progresses east, after a few cutters, we will be in the sweet spot!
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