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#1422435 - 28/04/2017 12:46 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
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Registered: 13/07/2007
Posts: 2752
Loc: Buderim
While there is no actual westerly winds along the equator, the trade winds are significantly below normal over a wide area. So westerly anomalies, even if not westerly actuals. Will still result in increased warming.

The subsurface cool pool is still peaking at between -2 and -3 anomaly, same as a month ago. Overall heat content of the equatorial pacific is down a little since the start of March, and is somewhat weak when compared to the start of previous el ninos. Not enough to prevent an el nino IMO, but might slow it down a little, or set up a strong switch to La Nina once it runs its course.

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#1422449 - 28/04/2017 14:26 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Locke Offline
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Registered: 27/12/2007
Posts: 4360
Loc: Brisbane
I read an article that Rossby waves generated following a strong El Nino lead to Kelvin waves with a reverse sign.

I'm having a little difficulty grasping the mechanics and was wanting to check my understanding.

Do Rossby waves propagate East to West not at the the equator but to the North and South of it following a strong El Nino event?

Would a reverse kelvin wave actually be expected to eventually lead to cooling in the Eastern pacific (the reverse of the Kelvin wave resulting from a WWB).

If so what does this mean in terms of our expectations of what should happen after an El Nino event. We know previous events have transitioned into La Nina's (or in the case of 82/83 at least cool neutral).

What's happened with the latest El Nino? Is the cool neutral a result of a kelvin wave with a reverse sign following a relatively strong Rossbay wave which followed the El Nino?

I can't help but think the warming in the East has been more a function of sub-surface wave action than any surface wind action. At the moment the subsurface in the East to me paints a picture of likely increased upwelling in coming months which should generate cooling in that area.
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This post and any other post by Locke is NOT an official forecast & should not be used as such. It's just my opinion & may or may not be backed by sound meteorological data. For official information, refer to Australian Bureau of Meteorology products.

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#1422450 - 28/04/2017 14:33 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Funkyseefunkydo]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 6621
Loc: Maryborough, Wide Bay, QLD
Originally Posted By: Funkyseefunkydo
I fail to see any westerly wind burst


There will be, I've marked it with the red arrow. Blue arrow represents solid trades persisting across the CPAC though.



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#1422522 - 30/04/2017 07:52 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Chris Stumer Offline
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Registered: 28/01/2010
Posts: 1602
Loc: Kingaroy
I wonder if the late season burst of tropical activity will help set up a WWB?

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#1422526 - 30/04/2017 09:09 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Locke]
snowbooby Offline
Weather Freak

Registered: 11/05/2016
Posts: 108
Originally Posted By: Locke
I read an article


Can you provide a link?

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#1422571 - 01/05/2017 08:49 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
snowbooby Offline
Weather Freak

Registered: 11/05/2016
Posts: 108

Thought this might provide some useful insight into current situation

"The Curious Case of the EL Niño That Never Happened: A Perspective from 40 Years of Progress in Climate Research and Forecasting"

http://journals.ametsoc.org/doi/full/10.1175/BAMS-D-14-00089.1

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#1422573 - 01/05/2017 09:38 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
ozone doug Online   content
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Registered: 06/11/2006
Posts: 1663
Loc: Roma SW QLD Eye to the West...
Thanks for that snowbooby ,That was a good read.
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#1422612 - 01/05/2017 21:51 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
RC Offline
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Registered: 29/09/2007
Posts: 2083
Loc: near Rockhampton, Qld
This months run of 3.4 anomalies will be interesting. Coming out of the uncertainty period.

CFS V2 already has changed it's tune to 3.4 only barely getting to El Nino thresholds. Although it is rather reactive.

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#1422723 - 03/05/2017 21:23 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 6621
Loc: Maryborough, Wide Bay, QLD
Down she goes again #El-Nada:


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#1422728 - 03/05/2017 21:51 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
RC Offline
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Registered: 29/09/2007
Posts: 2083
Loc: near Rockhampton, Qld
There is a bit of surface cooling along the South American coast where it was very hot before and some along the equator region in the same area.

What does it all mean?

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#1422745 - 04/05/2017 09:22 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Locke Offline
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Registered: 27/12/2007
Posts: 4360
Loc: Brisbane
Perhaps were still looking at residual sub surface wave action from the last strong el-nino.

Check the sub-surface anomaly graphics and you can see a "rebound" effect in the east.

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/wkxzteq.shtml
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This post and any other post by Locke is NOT an official forecast & should not be used as such. It's just my opinion & may or may not be backed by sound meteorological data. For official information, refer to Australian Bureau of Meteorology products.

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#1422750 - 04/05/2017 10:22 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Mega]
Mike Hauber Offline
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Registered: 13/07/2007
Posts: 2752
Loc: Buderim
Originally Posted By: Mega
Down she goes again #El-Nada:



Is that a reaction to westerly winds we have experienced the last week, which have been much more significant than anything else experienced in the last few months?

Or perhaps it is due to relying on noisy satellite SST readings which do not actually mean anything?

Whats the bet that the weekly nino 3.4 index values will not show any noticeable drop in the next few weeks? Remember the excitement about the month long drop in CDAS daily a couple months ago? Which resulted in only a barely noticeable blip in the continuing upward trend.



Current conditions are full steam ahead towards el nino.

Wind forecasts show a possible slowdown later in the month with trade winds getting back to close to normal, but we'll have to see how long this lasts, or whether it even occurs at all as forecast. More than a month as occurred in 2014 would slow things down a lot. Only a week or two is pretty much normal for any non-extreme el nino.

The curious thing about the current westerly activity is that it looks a lot like what happens in a mature el nino early in the decay phase. It is much stronger just a little south of the equator, and significant high pressure anomalies near SE Asia seem to be pushing the westerlies to the south. NW Pacific seems to want La Nina, but the rest of the Pacific wants el nino. Unless NW Pacific changes there won't be much of a typhoon season and strong WWBs during our winter spring will be hard to come by.

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#1422767 - 04/05/2017 16:33 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Mike Hauber]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 6621
Loc: Maryborough, Wide Bay, QLD
Originally Posted By: Mike Hauber
Originally Posted By: Mega
Down she goes again #El-Nada:



Is that a reaction to westerly winds we have experienced the last week, which have been much more significant than anything else experienced in the last few months?

Or perhaps it is due to relying on noisy satellite SST readings which do not actually mean anything?


Whats the bet that the weekly nino 3.4 index values will not show any noticeable drop in the next few weeks? Remember the excitement about the month long drop in CDAS daily a couple months ago? Which resulted in only a barely noticeable blip in the continuing upward trend.



Current conditions are full steam ahead towards el nino.

Wind forecasts show a possible slowdown later in the month with trade winds getting back to close to normal, but we'll have to see how long this lasts, or whether it even occurs at all as forecast. More than a month as occurred in 2014 would slow things down a lot. Only a week or two is pretty much normal for any non-extreme el nino.

The curious thing about the current westerly activity is that it looks a lot like what happens in a mature el nino early in the decay phase. It is much stronger just a little south of the equator, and significant high pressure anomalies near SE Asia seem to be pushing the westerlies to the south. NW Pacific seems to want La Nina, but the rest of the Pacific wants el nino. Unless NW Pacific changes there won't be much of a typhoon season and strong WWBs during our winter spring will be hard to come by.


LOL!

It's a combination of things. Firstly, those westerly winds you speak of are only occurring west of the dateline, and every time they do, they get replaced by trade winds again. Have you seen the 850hpa equatorial winds that are being forecast in the next week or two? Above average trades through the entire Pacific except the far east. I fail to see how that resembles 'full steam towards El-Nino.'

Secondly, why do you think many of the climate models have backed right off the El-Nino idea, especially as we near the predictability barrier? They did the same thing in 2014, when every man and his dog were banging on about a Super Nino later that year. Remember when a couple of months ago these models were saying "El-Nino by May 2017"? Well where is it? I'm still waiting.


Edited by Mega (04/05/2017 16:37)

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#1422771 - 04/05/2017 18:46 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Snowy Hibbo Offline
Weather Freak

Registered: 30/12/2016
Posts: 314
Loc: Matlock, Victoria.

There is currently a WWB from 130E to 170W, which covers all of the Western Pacific. Next week the WWB moves east, but further long term we should return to average trades.
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#1422781 - 04/05/2017 21:35 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
snowbooby Offline
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Registered: 11/05/2016
Posts: 108
Hmmm...just thought I’d mention an ancient paper(1991)”Influence of the Stratospheric QBO on Enso Variability” (Gray,Sheaffer and Knaff)postulating that phase of qbo may act as a trigger to el nino. I’m still trying to fathom it(no pun) so cant comment much but easterly phases is linked to el nino, westerly nina.

There’s a bit more than that of course - the authors do qualify their findings somewhat especially that the western warm pool must be present (optimally primed?) for the “trigger” to work. The qbo is currently in an easterly outgoing phase in the lowest reaches of the stratosphere - frustratingly they dont seem to spell out at what level they “read” the phase....

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#1422794 - 05/05/2017 07:43 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 6621
Loc: Maryborough, Wide Bay, QLD
EC is even more bullish on the upcoming burst of trades:


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#1422796 - 05/05/2017 08:22 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: snowbooby]
Multiversity Offline
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Registered: 28/03/2017
Posts: 76
Loc: Brisbane Inner West
WRT: QBO. I originally posted this in another thread, but saw the mention of QBO.

Came across this article in Science on a phenomenon called the quasi-biennial oscillation - QBO- which is quite intriguing. From my limited reading it is concerned with cycling stratospheric wind circulation which regularly reverses every 2- 3 years. This is thought to be driven by tropical circulation. However recently there hasn't been the anticipated reversal which sparks the question, why?

http://www.sciencemag.org/news/2016/09/u...t-winter-europe

Anybody familiar with this feature and what the current thinking is?
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#1422798 - 05/05/2017 09:08 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Multiversity]
Snowy Hibbo Offline
Weather Freak

Registered: 30/12/2016
Posts: 314
Loc: Matlock, Victoria.
Originally Posted By: Multiversity
WRT: QBO. I originally posted this in another thread, but saw the mention of QBO.

Came across this article in Science on a phenomenon called the quasi-biennial oscillation - QBO- which is quite intriguing. From my limited reading it is concerned with cycling stratospheric wind circulation which regularly reverses every 2- 3 years. This is thought to be driven by tropical circulation. However recently there hasn't been the anticipated reversal which sparks the question, why?

http://www.sciencemag.org/news/2016/09/u...t-winter-europe

Anybody familiar with this feature and what the current thinking is?
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This shows where the QBO occurs at about 30mb with the easterly phases being blue and westerly phases being red.


This is the current QBO situation in a westerly phase with the QBO jet circled in green around 30-50mb. A slight weakening of the westerlies is forecast on some models.
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#1422804 - 05/05/2017 10:00 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Chris Stumer Offline
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Registered: 28/01/2010
Posts: 1602
Loc: Kingaroy
Perhaps we could see La Nina this year? Especially if we keep getting good bursts of trades coming through and if the westerlies stop. The hot and dry summer of 2016/2017 would have consistent with a strong El Nino rather than neutral.

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#1422805 - 05/05/2017 10:25 Re: Climate Driver Discussion 2017 (Enso, IOD, PDO ,SAM etc) [Re: Mega]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 2752
Loc: Buderim
Originally Posted By: Mega


It's a combination of things. Firstly, those westerly winds you speak of are only occurring west of the dateline, and every time they do, they get replaced by trade winds again.

The normal pattern for el nino development is strong westerly winds to the west of the dateline, and alternating periods of westerly activity with return to normal trade winds. That is why they are called westerly wind bursts

Originally Posted By: Mega

Have you seen the 850hpa equatorial winds that are being forecast in the next week or two? Above average trades through the entire Pacific except the far east. I fail to see how that resembles 'full steam towards El-Nino.'


I said current conditions are full steam towards el nino. What may or may not happen in two weeks is not current conditions. CFS forecast for a return to normal conditions is quite consistent with what has happened in past developing el ninos. EC is a strong enough trade wind surge I'd expect it to put a significant slow down on development, but I note it looks similar strength to what happened in March, which had minimal impact on the recent warming trend.

Originally Posted By: Mega

Secondly, why do you think many of the climate models have backed right off the El-Nino idea, especially as we near the predictability barrier? They did the same thing in 2014, when every man and his dog were banging on about a Super Nino later that year.


CFS and POAMA have backed off considerably. But JMA has gone the other way and after a long period of being the one model forecasting cooler conditions it has joined many other models with a weak el nino forecast. NASA has gone from strong to moderate el nino. EC is holding steady, and has to me been the pick of the models for the last year, pretty much nailing last summer as being neutral when every other man and his dog were banging on about a la nina.

Originally Posted By: Mega

Remember when a couple of months ago these models were saying "El-Nino by May 2017"? Well where is it? I'm still waiting.


EC from January looks to have forecast the recent warming trend quite well. Looking back at archives the models from Jan and Feb have if anything predicted less warming than we have observed.


Edited by Mike Hauber (05/05/2017 10:26)

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