December Discussion II

[HoarfrostHubb]

Definitely AN for ORH

[40/70 Benchmark]

21 minutes ago, LibertyBell said:

Your pal raindance aka tacoman must be dancing in the streets of Albuquerque today- I heard today they're getting the first blizzard that city has ever experienced?

 

Cool...hope he enjoys it, but I still see zero sign that this is not behaving as a typical modoki.

[40/70 Benchmark]

27 minutes ago, HoarfrostHubb said:

ORH At +0.3F for the month.  Tale of two halves.   Def a shat pattern.

Walkway, trees here are glazed and icy.  Have not checked the driveway 32.0F

We verify.

I had a little coating of sleet and/or snow when I left the house like an hour ago....but nuisance crap.

It was raining and like 34*.

[Lava Rock]

Maybe 1" give or take

Sent from my Pixel 2 using Tapatalk

[moneypitmike]

5 minutes ago, 40/70 Benchmark said:

We verify.

I had a little coating of sleet and/or snow when I left the house like an hour ago....but nuisance crap.

It was raining and like 34*.

Congrats on a December with a couple traces!

[LibertyBell]

8 minutes ago, 40/70 Benchmark said:

Cool...hope he enjoys it, but I still see zero sign that this is not behaving as a typical modoki.

Yes all the early bridge jumpers not withstanding.  Winter has barely begun and they're already jumping off lol.  

[dmillz25]

1 hour ago, CoastalWx said:

The second half relaxation was fairly easily seen imo. The euro guidance correctly predicted it because of how it handled the MJO. What I’m curious about is how isotherm claims the stratosphere caused the mjo to go into overdrive. I admit that’s not my strong point so curious to see what he means. 

There is a lot of stuff going on so I’m not surprised guidance has changed quite a bit. 

Heard it has something to do with cooling in the tropical troposphere during an SSW. Apparently it happened last winter also

[40/70 Benchmark]

1 hour ago, CoastalWx said:

The second half relaxation was fairly easily seen imo. The euro guidance correctly predicted it because of how it handled the MJO. What I’m curious about is how isotherm claims the stratosphere caused the mjo to go into overdrive. I admit that’s not my strong point so curious to see what he means. 

There is a lot of stuff going on so I’m not surprised guidance has changed quite a bit. 

I agree. This was my contention with Tom (Isotherm's) contention that it was unpredictable.....sorry, I predicted it. The PNA was meager early on in the season in many of my analogs, and the month of December was iffy in general. No one should ever be caught off guard when December blows in an el nino season.

I do agree with Tom that it was impossible to determine which phase the MJO would be in during the third week of December at 3 months lead time, yes....but you didn't have to in order to anticipate a benign month IMO. I'm not impugning Tom's efforts....best seasonal forecaster that I have seen, but I just think that he missed it on December.

[weathafella]

Raindance is tacoman?

[Baroclinic Zone]

29 minutes ago, LibertyBell said:

Yes all the early bridge jumpers not withstanding.  Winter has barely begun and they're already jumping off lol.  

Month of MET winter in the books already.  The days are getting longer.  Pack it up.

[moneypitmike]

8 minutes ago, Baroclinic Zone said:

Month of MET winter in the books already.  The days are getting longer.  Pack it up.

Another 2 weeks and the early risers will notice the changing sunrise time.

[Hazey]

29 minutes ago, weathafella said:

Raindance is tacoman?

Soon to be the new Rev if he nails this winter.

[Isotherm]

1 hour ago, CoastalWx said:

The second half relaxation was fairly easily seen imo. The euro guidance correctly predicted it because of how it handled the MJO. What I’m curious about is how isotherm claims the stratosphere caused the mjo to go into overdrive. I admit that’s not my strong point so curious to see what he means. 

There is a lot of stuff going on so I’m not surprised guidance has changed quite a bit. 

 

@CoastalWx @40/70 Benchmark

 

This is in response to both of your inquiries.

I concur that it was easier to see from about the middle point of the month, once it became ostensible that the MJO would continue intensifying further beyond low-orbit. However, my contention is that this was not easily foreseen from the pre-season period in November, and but for the stratospheric induced MJO amplification, December would have finished less warm, and likely with more snow in the Northeast than it did. The literature demonstrates a trop-->strat-->trop pathway, whereby heightened tropospheric induced stratospheric perturbation, climaxing in a sudden warming event, can operate on a dual pathway, with the stratosphere thereupon modulating the intraseasonal signal and further amplifying it. This significant, anomalous amplification of the MJO, in my opinion, as a consequence of the major stratospheric event, was the curveball. A low-orbit MJO would not have ruined late December, in light of other background signals, which favored cooler December. I believe the argument has merit, further, as December was cooler than average through the latter point of the month, at which time the intraseasonal signal amplified materially, driving trough after trough into the Western US. There are numerous cases historically in which the MJO amplifies significantly contemporaneously with a significant stratospheric event, and this is not a coincidence in my view, due to the dual feedback pathway. We saw it last year, for example, wherein the MJO amplified quite strongly prior to the sudden warming event.

So, when I say, curveball/largely unforeseeable, I'm referring to from early/mid November, not a couple weeks ago. Yes, canonical Nino analogs supported a warm December, but we were not following the canonical Nino playbook as far as how we arrived at the result in my opinion. The primary reason for the decline of the pattern late December was the amplification of the intraseasonal signal, brought about largely by feedback from stratospheric modulation.

So, Ray, we'll have to agree to disagree on how the results arrived the way they did for December - as in my view, background signals supported a normal or cooler December. My initial winter forecast included a non-SSW year, so again, the resolution of it is immaterial to the rest of the winter, but I strongly believe this trop-strat->MJO interference aided significantly in hampering winter chances in the Northeast in late December.

[JBinStoughton]

59 minutes ago, moneypitmike said:

Congrats on a December with a couple traces!

Always nice to cash in early before climo gets us 

[40/70 Benchmark]

10 minutes ago, Isotherm said:

 

@CoastalWx @40/70 Benchmark

 

This is in response to both of your inquiries.

I concur that it was easier to see from about the middle point of the month, once it became ostensible that the MJO would continue intensifying further beyond low-orbit. However, my contention is that this was not easily foreseen from the pre-season period in November, and but for the stratospheric induced MJO amplification, December would have finished less warm, and likely with more snow in the Northeast than it did. The literature demonstrates a trop-->strat-->trop pathway, whereby heightened tropospheric induced stratospheric perturbation, climaxing in a sudden warming event, can operate on a dual pathway, with the stratosphere thereupon modulating the intraseasonal signal and further amplifying it. This significant, anomalous amplification of the MJO, in my opinion, as a consequence of the major stratospheric event, was the curveball. A low-orbit MJO would not have ruined late December, in light of other background signals, which favored cooler December. I believe the argument has merit, further, as December was cooler than average through the latter point of the month, at which time the intraseasonal signal amplified materially, driving trough after trough into the Western US. There are numerous cases historically in which the MJO amplifies significantly contemporaneously with a significant stratospheric event, and this is not a coincidence in my view, due to the dual feedback pathway. We saw it last year, for example, wherein the MJO amplified quite strongly prior to the sudden warming event.

So, when I say, curveball/largely unforeseeable, I'm referring to from early/mid November, not a couple weeks ago. Yes, canonical Nino analogs supported a warm December, but we were not following the canonical Nino playbook as far as how we arrived at the result in my opinion. The primary reason for the decline of the pattern late December was the amplification of the intraseasonal signal, brought about largely by feedback from stratospheric modulation.

So, Ray, we'll have to agree to disagree on how the results arrived the way they did for December - as in my view, background signals supported a normal or cooler December. My initial winter forecast included a non-SSW year, so again, the resolution of it is immaterial to the rest of the winter, but I strongly believe this trop-strat->MJO interference aided significantly in hampering winter chances in the Northeast in late December.

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Posted Wednesday at 04:27 AM

 

 

11-12-18

 

 

 

"The current scandinavian ridge should retrograde towards Greenland for the first couple of weeks of December, some significant snows are likely for much of New England. The PNA may struggle to become established this early, however if it can, the northern mid atlantic may join the fray. The  blocking pattern should break down mid month, and there will likely be Grinch storm in the vicinity of Christmas, unlike last season.Temperatures should average out near normal for most of the east by month's end, biased colder early, and milder late. If anything, slightly above average for the mid atlantic, and below average in New England".

 

 

 

"The NAO blocking breaks down in time for the holidays, go figure, however around this time the Pacific side grows more supportive, so this mid winter break will not be as prolonged, nor as mild as last season, especially across New England.

 

I will present the analogs that suggested this later, as I am at work, but what do you call this excerpt from my outlook issued on 11/12/18, a lucky guess?

I agree that its immaterial with regard to the balance of winter, and I am not suggesting that it is. I am actually a little more aggressive than you are with regard to seasonal snowfall...at least across SNE.

[MarkO]

Pattern sucks. But on the positive side, we got about an inch on Christmas, another half inch Wed night and 1.5" of cement today and it at least looks like winter up here. That rainer last week really put a beat down on the pack. 

[OSUmetstud]

The cold in early December wasn't via NAO blocking. The month averaged positive. 

[CoastalWx]

9 minutes ago, Isotherm said:

 

@CoastalWx @40/70 Benchmark

 

This is in response to both of your inquiries.

I concur that it was easier to see from about the middle point of the month, once it became ostensible that the MJO would continue intensifying further beyond low-orbit. However, my contention is that this was not easily foreseen from the pre-season period in November, and but for the stratospheric induced MJO amplification, December would have finished less warm, and likely with more snow in the Northeast than it did. The literature demonstrates a trop-->strat-->trop pathway, whereby heightened tropospheric induced stratospheric perturbation, climaxing in a sudden warming event, can operate on a dual pathway, with the stratosphere thereupon modulating the intraseasonal signal and further amplifying it. This significant, anomalous amplification of the MJO, in my opinion, as a consequence of the major stratospheric event, was the curveball. A low-orbit MJO would not have ruined late December, in light of other background signals, which favored cooler December. I believe the argument has merit, further, as December was cooler than average through the latter point of the month, at which time the intraseasonal signal amplified materially, driving trough after trough into the Western US. There are numerous cases historically in which the MJO amplifies significantly contemporaneously with a significant stratospheric event, and this is not a coincidence in my view, due to the dual feedback pathway. We saw it last year, for example, wherein the MJO amplified quite strongly prior to the sudden warming event.

So, when I say, curveball/largely unforeseeable, I'm referring to from early/mid November, not a couple weeks ago. Yes, canonical Nino analogs supported a warm December, but we were not following the canonical Nino playbook as far as how we arrived at the result in my opinion. The primary reason for the decline of the pattern late December was the amplification of the intraseasonal signal, brought about largely by feedback from stratospheric modulation.

So, Ray, we'll have to agree to disagree on how the results arrived the way they did for December - as in my view, background signals supported a normal or cooler December. My initial winter forecast included a non-SSW year, so again, the resolution of it is immaterial to the rest of the winter, but I strongly believe this trop-strat->MJO interference aided significantly in hampering winter chances in the Northeast in late December.

I guess my question is, does the warming causes a deeper and colder upper troposphere for tropical Convection? Is that what you implied?

[40/70 Benchmark]

Just now, OSUmetstud said:

The cold in early December wasn't via NAO blocking. The month averaged positive. 

The NAO dipped to begin the month.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml

Maybe I should not have used the term "blocking", as that implies sustainability, but I meant negative NAO. It was pretty clear from the December narrative that i did not expect it to persist.

[Isotherm]

6 minutes ago, 40/70 Benchmark said:

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Posted Wednesday at 04:27 AM

 

 

11-12-18

 

 

 

"The current scandinavian ridge should retrograde towards Greenland for the first couple of weeks of December, some significant snows are likely for much of New England. The PNA may struggle to become established this early, however if it can, the northern mid atlantic may join the fray. The  blocking pattern should break down mid month, and there will likely be Grinch storm in the vicinity of Christmas, unlike last season.Temperatures should average out near normal for most of the east by month's end, biased colder early, and milder late. If anything, slightly above average for the mid atlantic, and below average in New England".

 

 

 

"The NAO blocking breaks down in time for the holidays, go figure, however around this time the Pacific side grows more supportive, so this mid winter break will not be as prolonged, nor as mild as last season, especially across New England.

 

I will present the analogs that suggested this later, as I am at work, but what do you call this excrept from my outlook issued on 11/12/18, a lucky guess?

 

 

 

Great call - I don't think anyone else forecasted the month correctly w/ that level of detail. Regardless of our differences in reasoning, this was a great call for December.

[HIPPYVALLEY]

1 hour ago, HoarfrostHubb said:

ORH At +0.3F for the month.  Tale of two halves.   Def a shat pattern.

Walkway, trees here are glazed and icy.  Have not checked the driveway 32.0F

 Roads were not pretty in jGreenfield this morning.  downtown is OK now but it was real slick earlier.  

[Isotherm]

5 minutes ago, CoastalWx said:

I guess my question is, does the warming causes a deeper and colder upper troposphere for tropical Convection? Is that what you implied?

 

Correct, IMO that is a large part of the pathway. If we note z30, z70, etc., temperatures right now 25S-25N as a proxy, they're down near record lows, which enhances the convection signal. Do you agree with this line of reasoning?

 

[40/70 Benchmark]

Just now, Isotherm said:

 

 

 

Great call - I don't think anyone else forecasted the month correctly w/ that level of detail. Regardless of our differences in reasoning, this was a great call for December.

I def. thought that we would have availed of it with some snow early, though....tough break.

I agree with your rationale of how the SSW paradoxically promoted the short term relaxation.....and also agree that that specifically could not have been forecast at a seasonal level, but the more general trends were is my contention.

 

[Isotherm]

Just now, 40/70 Benchmark said:

I def. thought that we would have availed of it with some snow early, though....tough break.

I agree with your rationale of how the SSW paradoxically promoted the short term relaxation.....and also agree that that specifically could not have been forecast at a seasonal level, but the more general trends were is my contention.

 

 

Ok, we agree completely then. I'm mostly talking about the specific reasoning for this late December decline in sensible wx prospects.

And agree, most would have a different "flavor" of this month if the early December event ended up farther north.

[40/70 Benchmark]

5 minutes ago, Isotherm said:

 

Ok, we agree completely then. I'm mostly talking about the specific reasoning for this late December decline in sensible wx prospects.

And agree, most would have a different "flavor" of this month if the early December event ended up farther north.

I wonder if the paradoxical impact of the incipient SSW warmer pattern emerges from an analog perspective immediately preceding major SSW? It would be easy enough to find out, and thus specify as causation for a warmer interlude on a seasonal scale?

I'll bet that we can utilize this experience moving forward to more precisely forecast the evolution of the winter season....IOW, next time I will know to mention that impact of the nascent SSW when elucidating the rationale for a warmer interlude.

Fascinating-

[Isotherm]

2 minutes ago, 40/70 Benchmark said:

I wonder if the paradoxical impact of the incipient SSW warmer pattern emerges from an analog perspective immediately preceding major SSW? It would be easy enough to find out, and thus specify as causation for a warmer interlude on a seasonal scale?

I'll bet that we can utilize this experience moving forward to more precisely forecast the evolution of the winter season....IOW, next time I will know to mention that impact of the nascent SSW when elucidating the rationale for a warmer interlude.

Fascinating-

 

Ray -- I don't think it's a coincidence that sensible weather tends to be warmer than normal preceding and during sudden stratospheric warming events in the Eastern US. Historically, this is a fairly strong common denominator. As I said, last year had a similar temporal association w/ the MJO amplification. Certainly, correlation is not tantamount to causation, but in light of the available literature which seems to underscore this dual pathway, and the empirical evidence of MJO amplification concurrent with precursor stratospheric warming events, I think it's tenable to assert that 1) if you're expecting a SSW event, 2) forecast a warm period for the 10-15 days preceding / during the time wherein you expect it to occur.

The upside to all of this, is it could potentially render the core of the climatological period more productive this year.

[40/70 Benchmark]

Just now, Isotherm said:

 

Ray -- I don't think it's a coincidence that sensible weather tends to be warmer than normal preceding and during sudden stratospheric warming events in the Eastern US. Historically, this is a fairly strong common denominator. As I said, last year had a similar temporal association w/ the MJO amplification. Certainly, correlation is not tantamount to causation, but in light of the available literature which seems to underscore this dual pathway, and the empirical evidence of MJO amplification concurrent with precursor stratospheric warming events, I think it's tenable to assert that 1) if you're expecting a SSW event, 2) forecast a warm period for the 10-15 days preceding / during the time wherein you expect it to occur.

The upside to all of this, is it could potentially render the core of the climatological period more productive this year.

Thank you. Your work is very educational and has helped me tremendously over the past several years.

I will remember that...verification is great, but precise causation is needed in order for true mastery of material...as much as possible within this context, anyway.

[Isotherm]

1 minute ago, 40/70 Benchmark said:

Thank you. Your work is very educational and has helped me tremendously over the past several years.

I will remember that...verification is great, but precise causation is needed in order for true mastery of material...as much as possible within this context, anyway.

 

Thank you, Ray, and again, I didn't intend to imply that your call for this month was a lucky one. You've had a great handle on the pattern thus far. Hopefully, this winter will continue in accordance to what we've both forecasted.  

[michsnowfreak]

13 hours ago, dendrite said:

I feel like I will never top 07-08. Steve feels like he will never top Feb 15. Josh feels like he will never top 13-14.

That may all be true, but there’s something to be said that we’ve seen these historical stretches all over the last decade. In other words, never say never. I’ll keep holding out hope for eclipsing 12ft someday.

With the increasing snowfall this century, an undeniable trend here in the southern Great Lakes east into New England, I suppose it is possible we may one day exceed the snowfall total, which broke a record that had been in place since 1880 for Detroit's snowiest Winter. Its also definitely possible to see a wall-to-wall Winter with no breaks like that one, just probably not as harsh. What I just could not believe is that we had that much snow with that much cold. Shoveling a foot of snow in -50° wind chills? Snow drifts to top of barns in rural areas and tops of fences in most backyards? Daily ground blizzards and several snowy days with temps below zero? It should have been a tundra, not the snowiest winter on record. If I heard grandpa tell these stories without weather data to back it up, I wouldn't believe him for a minute.

[OSUmetstud]

25 minutes ago, 40/70 Benchmark said:

The NAO dipped to begin the month.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml

Maybe I should not have used the term "blocking", as that implies sustainability, but I meant negative NAO. It was pretty clear from the December narrative that i did not expect it to persist.

I mean im pretty sure it averaged positive during the first two weeks. There's a significant rise there into late week 1/early week 2 of the month. Trying to pin down the intraseasonal stuff is pretty difficult anyway. You could even argue that the confluence from the positive NAO was a contributor in the futility in the seemingly good pattern.