December-winter is finally here!

[Ginx snewx]

Cohen wrote a article saying the low is Asia might prevent us from having a great winter

great read and game on

http://www.aer.com/science-research/climate-weather/arctic-oscillation

[HIPPYVALLEY]

I can't believe how little snow has melted here. There are still snow draped branches everywhere. The ride back yesterday was unreal from the high points of Gardner west to Wendell the trees looked they had lost no snow.

32/31. Let the slow drip begin.

[Damage In Tolland]

Lol.. So now the worry is a low in Asia will ruin winter.

[Ginx snewx]

Lol.. So now the worry is a low in Asia will ruin winter.

take the time to read his latest blog link I provided,really great reading,totally misinterpreted by all snow

[moneypitmike]

Lol.. So now the worry is a low in Asia will ruin winter.

Was in gfld for my daughter's soccer game yesterday. Impressive tree damage in the yards down there.....plain to see why the outages took place. Snow in the treess will be go e today. Torch. 33.9/33

[Damage In Tolland]

take the time to read his latest blog link I provided,really great reading,totally misinterpreted by all snow

Yeah I read it yesterday and didn't get that from it at all

[CoastalWx]

It only takes one thing to make weenies worry. It's relevant to winter disco and I thought it was interesting he brought it up. I have no idea how that got turned into something about ruining winter. Jeez.

[mahk_webstah]

go with the coldest, snowiest model

given recent model performance perhaps go with ensemble set that has the most consistency in its members, and tends fit the pattern best?

[CoastalWx]

Well back in realityville.....

I'm sort of surprised how warm the EC is. I can understand why , but if you showed me the pattern just from 500mb contours, I wouldn't guess cold, but I would not guess so mild either across Canada. There is still a good block north of AK. I guess the EC just says I don't care and floods the NAMR with Pacific air. It does seem like the Pacific jet weakens near mid month. I also think storms coming up from the Deep South are messing with the mean. Members are all over the place with timing. The GEFS offer the chance of a miller b, while the euro is miller meh. It should be interesting to see how this works out. People along the coast should remember climo is hostile a good part of this month. Consider the November snow a bonus.

[Cold Miser]

It only takes one thing to make weenies worry. It's relevant to winter disco and I thought it was interesting he brought it up. I have no idea how that got turned into something about ruining winter. Jeez.

I don't even know what the hell I'm looking at half the time with some of those interpretations, but I saw nothing that hinted at crushing winter when reading that.

[RUNNAWAYICEBERG]

Mid Atlantic needs all the right pieces in place for a big winter. AllSnow should be worried. BUT up here in the north pole, we can get away with more.

[Damage In Tolland]

Let's start discussing the possible snow event Friday into Sat. Euro with closed low to the SW ang hfs more strung out with overrunning

[GaWx]

great read and game onhttp://www.aer.com/science-research/climate-weather/arctic-oscillation

I strongly recommend that people look at the absolutely fascinating animation of the high Oct. Eurasian snowcover sfc temp.'s minus the low Oct. Eurasian snowcover sfc temp.'s. that can be found at the very bottom of the link's write up. I just found this for the first time. Not only is it absolutely fascinating, but more importantly it should ease the worries (due to the expected mild first week of Dec.) of those expecting an overall cold E half of US DJF based on Cohen's work. According to that link's animation, the high Oct. Eurasian snowcover years are actually clearly biased solidly warmer in the E half of the US than low October Eurasian snowcover years during the first week of Dec!! Note the reds then. Then afterward, it gets close to a wash for the 2nd week of Dec. The relative mild returns one last time over most of the US for 12/13-19. After that, the blues (cold) dominate the E 2/3 of the US from 12/21 through 2/18 almost nonstop! Then 2/19-28 is back and forth. So, this animation suggests a solidly cold dominated 60 day period over the E 2/3 of the US during the climo coldest part of winter after a mild dominated 12/1-19. After looking at the E US, I then recommend folks focus on Greenland. Note that Greenland doesn't have reds dominating until ~12/18. Then, 12/18-2/13 is heavily dominated by relative warmth, which suggests a solid west based -NAO would be favored for the 12/18-2/13 period.

Did anyone else notice what I did for both the E 2/3 of the US and for Greenland? If so, any comments?

[Typhoon Tip]

Well back in realityville.....

I'm sort of surprised how warm the EC is. I can understand why , but if you showed me the pattern just from 500mb contours, I wouldn't guess cold, but I would not guess so mild either across Canada. There is still a good block north of AK. I guess the EC just says I don't care and floods the NAMR with Pacific air. It does seem like the Pacific jet weakens near mid month. I also think storms coming up from the Deep South are messing with the mean. Members are all over the place with timing. The GEFS offer the chance of a miller b, while the euro is miller meh. It should be interesting to see how this works out. People along the coast should remember climo is hostile a good part of this month. Consider the November snow a bonus.

 

Good! Neither would the operational Euro, either, with clear out to day 7, Texas-sized plumes of -20 to -30C at 850mbs passing over the breadth of the Shield in own periodicity.  Interesting interpretation there, , mild?  

 

Of course, I might be totally wrong in understanding what you are talking about, too. 

 

Folks, granted, it's not coming down here ... in a pattern that almost smacks of being anchored in a 4th phased MJO of moderate to higher than average strength, sure.  

 

Btw,  the whole of the Pacific appears to be in a positive/constructive wave interference pattern with regard to tropical forcing, when observing the OLR loops up to this point in time, and taking into consideration both observed and modeled wave guides from the various sources (Euro, GEFs wrt to heat and cool propagation and so forth); all of which is [conceptually] in agreement with a pattern that should struggle to bring cold south of the border.  

 

The upshot for snow/cold enthusiasts/obsessers//socially awkward internet anonymity/just flat on odd-ball types... is that it's transient through the 10th (never impossible in weather, though). Things should change shortly thereafter, and it may do so with an certain elan.  The GEFs PNA over at CDC and CPC is about as well clustered, tightly so, as can be allowed when still having to atone for at least some chaos in a medium intrinsically plagued by it.  Seriously, every member at CDC is within decimal points of the same SD value some 14 days out in time, taking the index from ~ -1.5 to +2.5!

 

Considering just how large the PNA domain is ... something is going to have to give.  I like the subtly negative EPO being subtly positive by week two, while the PNA is rising, because the longer term correlation between those two fields is a moderately negative one; which means there is a relative disconnect there, and when the PNA is negative, the EPO "tends" to be positive, vice versa and so on. So, that "somewhat" suggest when the PNA rises, it may be a stable pattern when it does (at least from the PNA ->> PNAP region).  

 

Throw in that the MJO is around the circle by then, either rejuvenating and/or weakening in the 7th wave space (which continues along the lines of a constructive interference down wind of its tropical forcing into the Pac circulation), that only slopes the probability even more in favor of western ridge, eastern trough couple across North America by week two -- possibly one of some amplitude in the means at that.

 

Until that happens, the operational runs that show our 850's flopping modestly over both sides of 0C, with meager precipitation chances, ...they would appear to be a better fit here.  

[Isotherm]

I strongly recommend that people look at the absolutely fascinating animation of the high Oct. Eurasian snowcover sfc temp.'s minus the low Oct. Eurasian snowcover sfc temp.'s. that can be found at the very bottom of the link's write up. I just found this for the first time. Not only is it absolutely fascinating, but more importantly it should ease the worries (due to the expected mild first week of Dec.) of those expecting an overall cold E half of US DJF based on Cohen's work. According to that link's animation, the high Oct. Eurasian snowcover years are actually clearly biased solidly warmer in the E half of the US than low October Eurasian snowcover years during the first week of Dec!! Note the reds then. Then afterward, it gets close to a wash for the 2nd week of Dec. The relative mild returns one last time over most of the US for 12/13-19. After that, the blues (cold) dominate the E 2/3 of the US from 12/21 through 2/18 almost nonstop! Then 2/19-28 is back and forth. So, this animation suggests a solidly cold dominated 60 day period over the E 2/3 of the US during the climo coldest part of winter after a mild dominated 12/1-19. After looking at the E US, I then recommend folks focus on Greenland. Note that Greenland doesn't have reds dominating until ~12/18. Then, 12/18-2/13 is heavily dominated by relative warmth, which suggests a solid west based -NAO would be favored for the 12/18-2/13 period.

Did anyone else notice what I did for both the E 2/3 of the US and for Greenland? If so, any comments?

 

 

Yes, I noticed that as well. The forecasted tropospheric pattern (IMO) fits well with the expected precursor regime for early season stratospheric vortex disruption. One can see on that temperature progression the transient +EPO episode that's liable to occur for the second week of December, prior to the retrogression of the GOA low into the Aleutians and thus the resumption of AK blocking. The good news here though (I just made a post about it in the NY forum: http://www.americanwx.com/bb/index.php/topic/44994-rising-confidence-in-favorable-period-for-snow-dec-15-jan-1/page-4?) is the AO looks to remain predominately negative prior to the occurrence of any SSW. The impressive poleward heat flux over the past week and current near splitting of the vortex in the stratosphere should aid in promoting a negative tendency to the AO for December, even if a SSW doesn't occur until later in the month or the beginning of January. Bottom line: I don't see any cause for concern with the current progression of both the tropospheric and stratospheric patterns.

[Typhoon Tip]

Why is it that when someone like Cohen, who's been merely lucky enough to be in the right place at the right time to have captured some lime ... puts out some article that espouses everything that we, here, locally to this source/blog, have painstakingly pointed out ... scratch that, pounded out, multiple times, WHILE it was happening, people post excerpts like it is some holy grail in awe...

 

Come on man. Gimme a break!  That snow/ice recovery thing and what it means, based upon probability as derived from climate studies could not be more passe. 

[GaWx]

Yes, I noticed that as well. The forecasted tropospheric pattern (IMO) fits well with the expected precursor regime for early season stratospheric vortex disruption. One can see on that temperature progression the transient +EPO episode that's liable to occur for the second week of December, prior to the retrogression of the GOA low into the Aleutians and thus the resumption of AK blocking. The good news here though (I just made a post about it in the NY forum) is the AO looks to remain predominately negative prior to the occurrence of any SSW. The impressive poleward heat flux over the past week and current near splitting of the vortex in the stratosphere should aid in promoting a negative tendency to the AO for December, even if a SSW doesn't occur until later in the month or the beginning of January. Bottom line: I don't see any cause for concern with the current progression of both the tropospheric and stratospheric patterns.

 

Regarding SSW:'s:

 Whereas there's no doubt that a strong SSW tends to lead to a more -AO at some point afterward, it is far from necessary to have it for even a very -AO imo. Here's why:

1. I looked in this table for sub -2 AO months:

 

 http://www.cpc.noaa.gov/products/precip/CWlink/daily_ao_index/monthly.ao.index.b50.current.ascii.table

 

2. Next, I went to here to look for SSW's that were either within that month or within two months prior to it:

 http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/

 

3. Results:

- 1/1980: -2.066;  no SSW found

- 1/1985:-2.806;  SSW found

- 2/1986: -2.904;  SSW found in 1/1986

- 2/1995: -2.127; no SSW found

- 1/1998: -2.081; SSW found in late 12/1997

- 12/2000: -2.354; SSW found

- 12/2005: -2.104; no SSW found

- 12/2009: -3.413; no SSW found

- 1/2010: -2.587; no SSW found til late Jan., which would be too late to affect most of the month

- 2/2010: -4.266; SSW found in late January 2010

-12/2010: -2.631; no SSW found

- 3/2013: -3.185; SSW found in early January (I guess that is recent enough to possibly be related)

 

Summary: For the 12 mos. with sub -2 AO, I found SSW's for only 6 (50%) that could have been a contributing cause of the very -AO.

 

Conclusion: Although it helps, a recent SSW is not even close to being necessary for a very strong -AO month imo since only half of the ones since 1979 had one that could possibly be attributed to it per the datasource that I use. Granted, others may have a different way to determine if there is an actual "SSW" and not use the source I used. That would lead to disagreements.

[Ginx snewx]

Yeah I read it yesterday and didn't get that from it at all

that's a different one

[Ginx snewx]

I strongly recommend that people look at the absolutely fascinating animation of the high Oct. Eurasian snowcover sfc temp.'s minus the low Oct. Eurasian snowcover sfc temp.'s. that can be found at the very bottom of the link's write up. I just found this for the first time. Not only is it absolutely fascinating, but more importantly it should ease the worries (due to the expected mild first week of Dec.) of those expecting an overall cold E half of US DJF based on Cohen's work. According to that link's animation, the high Oct. Eurasian snowcover years are actually clearly biased solidly warmer in the E half of the US than low October Eurasian snowcover years during the first week of Dec!! Note the reds then. Then afterward, it gets close to a wash for the 2nd week of Dec. The relative mild returns one last time over most of the US for 12/13-19. After that, the blues (cold) dominate the E 2/3 of the US from 12/21 through 2/18 almost nonstop! Then 2/19-28 is back and forth. So, this animation suggests a solidly cold dominated 60 day period over the E 2/3 of the US during the climo coldest part of winter after a mild dominated 12/1-19. After looking at the E US, I then recommend folks focus on Greenland. Note that Greenland doesn't have reds dominating until ~12/18. Then, 12/18-2/13 is heavily dominated by relative warmth, which suggests a solid west based -NAO would be favored for the 12/18-2/13 period.

Did anyone else notice what I did for both the E 2/3 of the US and for Greenland? If so, any comments?

yes I most certainly did, thats a 2010 2011 winter blueprint

[Isotherm]

That's good data Larry, and further lends credence to the notion that other forcing mechanisms induce a negative AO beyond a SSW, and additionally, often times a warm stratosphere w/ persistent disruption of the vortex can be sufficient (i.e., a major warming event superfluous). Other times, like 2011-12, the tropospheric pattern is so poor and unfavorable for blocking that stratospheric happenings don't matter. That's why it's extremely risky to have a tropospheric forecast hinging upon stratospheric progression. The good news here is the troposphere already appears primed for blocking regardless of the SSW timing. This could be due to a number of forcings such as tropical convection, +ENSO, -QBO / solar forcing, etc.

[Ginx snewx]

Why is it that when someone like Cohen, who's been merely lucky enough to be in the right place at the right time to have captured some lime ... puts out some article that espouses everything that we, here, locally to this source/blog, have painstakingly pointed out ... scratch that, pounded out, multiple times, WHILE it was happening, people post excerpts like it is some holy grail in awe...

Come on man. Gimme a break! That snow/ice recovery thing and what it means, based upon probability as derived from climate studies could not be more passe.

33 published papers, are you ok?

[weathafella]

33 published papers, are you ok?

Yeah I smell sour grapes from someone who didn't publish his work,,,,lol.

[Typhoon Tip]

 

Regarding SSW:'s:

 Whereas there's no doubt that a strong SSW tends to lead to a more -AO at some point afterward, it is far from necessary to have it for even a very -AO imo. Here's why:

1. I looked in this table for sub -2 AO months:

 

 http://www.cpc.noaa.gov/products/precip/CWlink/daily_ao_index/monthly.ao.index.b50.current.ascii.table

 

2. Next, I went to here to look for SSW's that were either within that month or within two months prior to it:

 http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/

 

3. Results:

- 1/1980: -2.066;  no SSW found

- 1/1985:-2.806;  SSW found

- 2/1986: -2.904;  SSW found in 1/1986

- 2/1995: -2.127; no SSW found

- 1/1998: -2.081; SSW found in late 12/1997

- 12/2000: -2.354; SSW found

- 12/2005: -2.104; no SSW found

- 12/2009: -3.413; no SSW found

- 1/2010: -2.587; no SSW found til late Jan., which would be too late to affect most of the month

- 2/2010: -4.266; SSW found in late January 2010

-12/2010: -2.631; no SSW found

- 3/2013: -3.185; SSW found in early January (I guess that is recent enough to possibly be related)

 

Summary: For the 12 mos. with sub -2 AO, I found SSW's for only 6 (50%) that could have been a contributing cause of the very -AO.

 

Conclusion: Although it helps, a recent SSW is not even close to being necessary for a very strong -AO month since only half of the ones since 1979 had one that could possibly be attributed to it. Granted, others may have a different way to determine if there is an actual "SSW" and not use the source I used. That would lead to disagreements.

 

 

 

It's too bad Eastern WX Forums is gone, because this was pointed out by myself and others, way back in 2005. Actually, none of this is really new in academia.  Most scholars/scientists of the science know of speculative/suppositional works going back to the 1960s in some cases depending on specific disciplines under the general arc of AO.  

 

Anyway, the key is propagation wrt to SSWs...  The warm onset/burster has to downwell in time (propagate downward), and that can be exemplified beautifully in the case of 1980 -vs- the 1985 negative AO cases.  

 

Here is 1985,

 

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_ANOM_ALL_NH_1985.gif

 

Here is 1980,

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_ANOM_ALL_NH_1980.gif

 

and what you are looking for is annotated below in a case as recent as 2004,

 

 

Notice also the counter-balancing cool anomaly that occurs shortly after the initial warm burst takes place at very high altitudes. That region goes on to over-lay the warm nodes as it weakens and down wells out in time.  

 

Once the warm node begins to interact with the tropopausal height levels within the mean PV its self, it weakens the static instability of the vortex and that can be math/physically show to stimulate a weakening/southward migration of the band of westerlies that circumvallates the vortex. Once that happens, it leaves blocking nodes behind.  

 

This establish and/or enhances the cold conveyors around the hemisphere... 

 

This whole play- takes 15 to 30 days to complete. It takes time for the propagation to descend and interact, then stimulate all these changes, and that can be shown by studying the subsequent -AO ... and noting a lag time needs to be applied to see the correlation. 

[CoastalWx]

Well the post about the NW Asian low was brought on by Cohen himself, not some weenie. He brought it up. Regardless, the other metrics look great, so it may not mean much of anything.

[Typhoon Tip]

33 published papers, are you ok?

 

Steve, that doesn't matter; you're missing the point. 

He stating stuff we already pointed out. Why is it magically more meaningful to you or anyone else.  

 

Look, I understand the need for refereeing source material through the vetting process of higher peers and scientists and all that crap. But it should ring particularly truer than what one already knows or suspects.  

 

Meh, to me it's it head nod in their favor and a, "yeah, I agree, it's been air apparent for decades"

[Typhoon Tip]

Yeah I smell sour grapes from someone who didn't publish his work,,,,lol.

 

Bite me!  

 

I don't publish because I am routinely ignored - so go f ur self

[Ginx snewx]

Well the post about the NW Asian low was brought on by Cohen himself, not some weenie. He brought it up. Regardless, the other metrics look great, so it may not mean much of anything.

You guys need to read the later blog I linked,

[Go Kart Mozart]

I think Cohen is saying we need to start a 2015-2016 speculative thread....because this winter is toast.

 

Seriously, GaWx...good stuff...drop by more often!

[Ginx snewx]

Bite me!

I don't publish because I am routinely ignored - so go f ur self

Tip, couple of things, Eastern is still online, 2005? Dude Cohen has papers on this in 1994. Nobody ignored you, you didn't break ground though

[Damage In Tolland]

Dear God