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#1461566 - 12/04/2018 14:31 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Locke Offline
Weatherzone Addict

Registered: 27/12/2007
Posts: 4446
Loc: Brisbane
Do you need 100% for a consensus? I've certainly seen cases where less than 100% has been described as a consensus?
_________________________
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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#1461569 - 12/04/2018 15:20 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Mega]
Mike Hauber Offline
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Registered: 13/07/2007
Posts: 3059
Loc: Buderim
Originally Posted By: Mega

Mike, not sure how you can deny that the consensus by these models was towards El-Nino last year..


Towards el nino is not el nino.

I would agree that there was a consensus of either warm neutral or el nino. I will never agree that there was a consensus of el nino.

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#1461570 - 12/04/2018 15:33 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Locke]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3059
Loc: Buderim
Originally Posted By: Locke
Do you need 100% for a consensus? I've certainly seen cases where less than 100% has been described as a consensus?


Not 100%, but close to it IMO. The dictionary definition Kino referred to includes both 'Unanimity' and 'most'.

I've had a couple group decision making experiences where one person was asked to change their opinion for the sake of achieving 'consensus'.

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#1461572 - 12/04/2018 15:57 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Mega]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3059
Loc: Buderim
Originally Posted By: Mega


Mike, not sure how you can deny that the consensus by these models was towards El-Nino last year...have a good look around social media etc...there have been several Mets on twitter commenting on how poorly they performed prior to the predictability barrier last year. In fact I'm yet to really see anyone but yourself defending them!


And a quick note on the predictability barrier. The switch happened late in terms of the predictability barrier:



While the worst performing forecasts were around April/May, by June (July discussion) the forecast hadn't reduced by all that much, with the majority of models still forecasting above 0 nino 3.4. By mid June the accuracy of 6 month forecast is usually in the upper half of all months.

So either the predictability barrier is changing, or it wasn't an issue of the predictability barrier.

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#1461577 - 12/04/2018 16:40 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Mike Hauber]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 18393
Loc: Burnett Heads
Originally Posted By: Mega


there have been several Mets on twitter commenting on how poorly they performed prior to the predictability barrier last year. In fact I'm yet to really see anyone but yourself defending them!




That's because they were indefensible and were reactive as we discussed last year. The predictability barrier is named as such for a very good reason.
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"Don't steal. The government hates competition."

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#1461588 - 12/04/2018 19:19 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 432
Loc: Pinjarra Hills, Qld
A forecasting predictability barrier as a concept may be reasonable but is probably not a line, but region of more uncertainty. Unpredictable because of divergence from actual past climate conditions, or divergence from what is known and what we expect from that knowledge, or both.

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#1461605 - 13/04/2018 07:32 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3059
Loc: Buderim
Unpredictability barrier - During late summer, monsoon trough moves well south of the equator and feedback between SST and trade winds weakens. ENSO event decays. During Autumn the monsoon trough moves near the equator and the feedback strengthens, and whatever ENSO state is in place starts to amplify again. It is hard to predict which side of 0 the decay phase will end in, and hard to predict whether the ENSO event will amplify towards warm or cold as the decay phase ends. There is a further period in late winter/spring when the monsoon trough gets a long way north of the equator when the feedback weakens. But it is usually still strong enough to maintain an event. Monsoon activity in the NH is strong in both the west and east, which increases the strength of feedback in the NH, compared to SH where monsoon activity is pretty much absent from the SE Pacific (at least in terms of lows/cyclones).

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#1461694 - 13/04/2018 21:05 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 432
Loc: Pinjarra Hills, Qld
Mike thanks for sharing your perspective on knowledge.
What is known and what we expect from that knowledge for forecasting predictability is still a question at play (and probably will be in perpetuity).

Locke's comment on consensus is also very relevant for knowledge.

While there are pointed discussions in this thread it continues to be informative and entertaining. I M O
😶

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#1461732 - 14/04/2018 12:39 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7421
Loc: Adelaide Hills.
From a different perspective....

For the lack of a better description, South Australia has been stuck in a predominantly NE-SE air-stream, with light-to-moderate winds for about 3 months. In terms of ENSO stuff, this would imply prevailing easterly winds up to about the latitude of Cairns, or thereabouts. As the 576-line has been arcing NE towards Cairns [for much of those 3 months], the tropospheric thickness south-of has be lower, under the influence of milder upper-trough conditions. These would interfere with, rather than enhance, tropical influences, with easterly winds off the Coral Sea. Even with several attempts by the longer-wave trough system, glancing Tasmania and much of the more-Southerly Eastern Seaboard, the thickness did not move much. The influence was synonymous of El Nino (a milder one perhaps, if you could call it that), however more locally-influenced by the persistence of upper ridges* (this is an analysis, so Iím not talking prognostic models) and interior easterly winds down/near the Great Dividing Range. This may have contributed to the higher/record day-time maximum temperatures north and east of Adelaide recently (this past week to the 12th).

* Upper ridges make the upper air warmer than it would otherwise be, reducing lapse rates and bringing more tropospheric stability.


Edited by Seira (14/04/2018 12:48)

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#1461845 - 15/04/2018 21:08 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7421
Loc: Adelaide Hills.
N.B.:

Much of the semantics regarding use of terminology in climate-driver related threads is something that could be considered superfluous in a broader context -- considering the fact that anyone can view/read these comments from anywhere online -- even from this perspective, I get a "not secure" notice when viewing these threads...which is something I think reasonable and pertinent to keep in mind.


Edited by Seira (15/04/2018 21:16)

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#1461873 - 16/04/2018 12:06 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 6922
Loc: Maffra, Central Gippsland, Vi...
As long as the rationale for predictions, or counter views on such are stated - all good debate IMO.

....we all learn.

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#1462064 - 19/04/2018 07:28 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3059
Loc: Buderim
MJO had been forecast to briefly amplify in phase 7 and then go weak again very quickly. However since then it has remained solid, with forecasts continuing to show a weakening that has so far not happened.



MJO is now well into the La Nina favourable Indian side. The link between MJO and trade winds seems to have been much weaker, with the last and so far the current Indian side phases producing little enhanced trades. And the recent trip through the Pacific has produced little westerly activity.



Kelvin wave activity from previous WWB has progressed and warm subsurface now covers the entire Pacific. There is one kelvin wave starting to impact the far east, and another one started in the west.



Heat content has no risen to levels usually associated with el nino.


Highly likely to see sustained warming over the next 1-2 months as all this subsurface activity surfaces. Trades could modify this, but at the moment it seems that trade activity is mostly quite close to average, and as long as this continues means no cooling, and steady but not rapid warming. Short term forecasts hint at westerly activity ramping up again in the next week or two.

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#1462086 - 19/04/2018 11:44 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
RC Offline
Weatherzone Addict

Registered: 29/09/2007
Posts: 2254
Loc: near Rockhampton, Qld
I am not convinced yet. That warmer water might only be a sliver a few kilometres metres wide. The sea level anomalies to not seem to indicate a huge amount of warmer water under there.

Time will tell.

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#1462382 - 22/04/2018 16:38 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Petros]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7421
Loc: Adelaide Hills.
Originally Posted By: Petros
As long as the rationale for predictions, or counter views on such are stated - all good debate IMO.

....we all learn.

From what I have seen, it's quite clear... while I have nothing against it (people can express their views as they like on here)... that this space suffers in the pure science and evidence department... or much incentive on that side of things. It is a weather forum, however, and I acknowledge that. If it is to be a more diverse weather forum, for anyone interested in any weather, weather phenomena, understanding the weather, climate and so on, then I'd say past issues need to be left alone, and a different approach considered.


Edited by Seira (22/04/2018 16:41)

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#1462412 - 22/04/2018 21:56 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Seira]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 432
Loc: Pinjarra Hills, Qld
Originally Posted By: Seira

... suffers in the pure science and evidence department... or much incentive on that side of things. It is a weather forum, however, and I acknowledge that. If it is to be a more diverse weather forum, for anyone interested in any weather, weather phenomena, understanding the weather, climate and so on, then I'd say past issues need to be left alone, and a different approach considered.


Well said. Though I do think there is some twist in what 'pure science' is, or perhaps it has never been pure. There are always motives, even if only subconscious.

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#1462414 - 22/04/2018 23:20 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7421
Loc: Adelaide Hills.
Hi Flowin smile .

Pure science as in a reliance on more facts and established principles of science that can be referenced/found online/in textbooks...rather than more guess work, speculation or coincidence. And yes, much of this could relate to choice.


Edited by Seira (22/04/2018 23:24)

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#1462454 - 24/04/2018 08:40 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3059
Loc: Buderim
Westerly wind activity again in the western Pacific.



This is forecast to continue and strengthen in the near future, and I'd say this is enough to push the chances of an el nino well above 50% now.

Interesting to see what BOM status will be today. They require 1/3rd of models to forecast 0.8 or higher by Spring, which is currently not the case, although a majority are now forecasting above 0.5 by summer. Interestingly if this requirement was met then that would satisfy the requirements not just for a watch, but maybe for an alert, - depending on whether the strong westerly activity in the far west over the last few months qualifies as being extensive enough to qualify as 'western Pacific' as opposed to far western only.

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#1462466 - 24/04/2018 12:51 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 6973
Loc: Maryborough, Wide Bay, QLD

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#1462469 - 24/04/2018 15:06 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3059
Loc: Buderim
BOM update continues inactive ENSO status. I disagree with one of their comments:

Quote:
Beneath the surface, the tropical Pacific Ocean is slightly warmer than average, but well within the neutral range.


Warm water volume is currently very high, and higher than even the peak of several significant past el ninos such as 06/07 or 09/10.


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#1462489 - 24/04/2018 21:21 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 432
Loc: Pinjarra Hills, Qld
Amazing plot. Thanks for sharing Mike.
I don't know the significance of a five month running mean perhaps other than smoothing or is there a tangible reason that five months is significant?
Plots with different running mean can show or hide signals at different time periods, so it always begs the question of differences in shorter and longer averaging period signal .Lag is another question.
So much yet to explore in climate drivers and signals ...

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