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#1463414 - 08/05/2018 21:09 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Seira]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 526
Loc: Pinjarra Hills, Qld
Originally Posted By: Seira
Originally Posted By: Locke
In the end though I guess the title doesn't matter as much if people understand what the thread is for and use it accordingly.

On that point I agree smile .

I agree also label not so important, compared to say clear intent.
Clear intent "what the thread is for" maybe needs improving..
Could we say something like:
- short term trends, evident in recent obs/analysis and expected relative 'short' terms outlook in models and extrapolated recent obs analysis, for "established" cycles in climate such Enso, and associated patterns, IOD, Sam and perhaps MJO in the mix
- relevant "established" longer term sway/ influence/ trend acting on the short term cycle (PDO?)
- excluding emerging theory and speculation on longer term, and natural vs not natural long term change to the extent that influence on short term is significantly questionable

This would of course depend on long term vs short term 'fence line' so I would say short term is maximum up to 2-3 yrs (preferably months ahead), and long term minimum around 20-30 years (preferably over decades at least)

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#1463420 - 09/05/2018 00:09 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Cutofflow Offline
Weather Freak

Registered: 14/08/2009
Posts: 100
Loc: North Central. VIC
Large dry cutoff low with no moisture from the NW, bad signs for inland growers around the south-east still waiting on a winter break, lots of wind and no rainfall North and West of the great divide. A series of blocking high pressure systems to follow, symptomatic of the +IOD phenomenon.

East Indian ocean staying cold, DMI positive = bad growing season ahead


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#1463434 - 09/05/2018 10:37 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
snowbooby Offline
Weather Freak

Registered: 11/05/2016
Posts: 202
SOI's downward leg - if trend-line drawn from about last October, July peak +2?

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#1463435 - 09/05/2018 10:45 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Locke]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 18549
Loc: The Beach.
Originally Posted By: Locke


In the end though I guess the title doesn't matter as much if people understand what the thread is for and use it accordingly.


Correct.

If people lack the ability to deduct from the title what can and cannot be discussed then that says more about them than the title and so does their need for change for change's sake. It's an attention thing and the thread has been taken way OT on many occasions anyway for the same reason. It won't matter what it is called, there will always be those who will try to push the boundaries and muddy the water.

Some people think AGW is a natural climate cycle. So should that be included ? Good luck with that one.

The title is quite self explanatory and the admin of this site have made it perfectly clear that AGW discussion is off the table. For the record the title you suggested over the page won't fit if all of the acronyms are listed, and they only scratch the surface anyway, hence why it was shortened originally and "etc" added on the end to broaden the range and encourage people to use common sense.
_________________________
"water has c.30x the heat capacity of air. Someone drop the penny please for those fixated on the notion that the atmosphere is the driver ( preferably in 3D)".

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#1463460 - 09/05/2018 17:59 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Cutofflow]
Thunderstruck Offline
Lightning man

Registered: 10/05/2001
Posts: 14961
Loc: Seaford Meadows, SA
Originally Posted By: Cutofflow
Large dry cutoff low with no moisture from the NW, bad signs for inland growers around the south-east still waiting on a winter break, lots of wind and no rainfall North and West of the great divide. A series of blocking high pressure systems to follow, symptomatic of the +IOD phenomenon.

East Indian ocean staying cold, DMI positive = bad growing season ahead



This is misleading. The type of low that will develop over the weekend and give the great rainfall to the Gippsland region and surrounds is not a typical signature of a low influenced by moisture from NW Australia/Indian etc. This is merely a classic case of cold air aloft from a surging upper trough interacting with the warmer seas off NSW in a typical manner seen many, many times over the years, these types of lows historically can be very large and intense. Pacific moisture is at play here and that is the key....plenty of it available as well.

Now had this low formed in the Bight and the moisture been not available then the argument is more valid.

Right now we are in a period of enhanced trades across the top end of Australia and right into the Indian. There is not much moisture available to come down, highs are dominating but this is far from unusual in May. Just cast your mind back to 2005 when a similar pattern persisted. Also 1996 had a similar tendency. Winter came strongly in both those years, and this year will be no different. Once those easterlies break down in the Indian, we will see a response in moisture building off NW Aus as the cooler water moves away and is replaced by warmer water. June-September is the period I am especially looking for across southern Australia generally to be at least average to above average in the growing season. Late start, good finish. There is nothing positive IOD that I can see about the pattern aside from the immediate situation but that is not expected to continue. I'd be more concerned if we were getting these easterlies in the middle of July.

All climate models have now come on board for a neutral to negative IOD event. No members even make it to positive. It won't be of the 2016 standard, but at least a weak to possibly moderate event. There has been a swing toward a negative IOD in recent updates as opposed to away. So for now, short term pain, but in time the response will come.

TS cool


Edited by Thunderstruck (09/05/2018 18:03)

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#1463464 - 09/05/2018 18:58 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mega Offline
Meteorological Motor Mouth

Registered: 03/02/2003
Posts: 7210
Loc: Maryborough, Wide Bay, QLD
Completely agree TS, good post.

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#1463465 - 09/05/2018 19:39 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 526
Loc: Pinjarra Hills, Qld
Thanks TS. Informative to me, I am more familiar with tropics /subtropics climate so discussion about the southern states / southern regions of Australia interests me.
When you say pacific moisture at play and plenty of it, is there a specific product or report status to understand that?

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#1463470 - 09/05/2018 20:03 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 526
Loc: Pinjarra Hills, Qld
Originally Posted By: ColdFront
Originally Posted By: Locke


In the end though I guess the title doesn't matter as much if people understand what the thread is for and use it accordingly.


Correct.

If people lack the ability to deduct from the title what can and cannot be discussed then that says more about them than the title and so does their need for change for change's sake.
....

The title is quite self explanatory and the admin of this site have made it perfectly clear that AGW discussion is off the table.


Agree, but labels do influence people. As long as it is understood that many things discussed are probably responses rather than drivers, I agree don't need to change for change sake.

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#1463479 - 09/05/2018 21:59 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Thunderstruck]
_Johnno_ Offline
Weatherzone Addict

Registered: 08/11/2009
Posts: 1745
Spot on TS! Right on the money! Could not of said it better myself
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#1463511 - 10/05/2018 13:44 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Flowin]
ColdFront Offline
Meteorological Motor Mouth

Registered: 29/06/2008
Posts: 18549
Loc: The Beach.
Originally Posted By: Flowin
As long as it is understood that many things discussed are probably responses rather than drivers


I've said as much for years, particularly where ENSO models and the MJO are concerned. However something drives the response. smile
_________________________
"water has c.30x the heat capacity of air. Someone drop the penny please for those fixated on the notion that the atmosphere is the driver ( preferably in 3D)".

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#1463648 - 11/05/2018 09:05 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3302
Loc: Buderim
Currently there is quite a significant subsurface warm pool built up in the central Pacific.



Same date 97 shows that el nino development was much further ahead:



However the subsurface warming is a long way ahead of the same stage in development of the 2009 el nino.


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#1463704 - 11/05/2018 21:09 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
RC Offline
Weatherzone Addict

Registered: 29/09/2007
Posts: 2339
Loc: near Rockhampton, Qld
I am not convinced of a forthcoming El Nino yet. I am wondering if this current warm water will run out of puff and it will revert to a larger La Nina.

Probably overdue for a La Nina now.

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#1463712 - 11/05/2018 22:05 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Mike Hauber]
snowbooby Offline
Weather Freak

Registered: 11/05/2016
Posts: 202
Originally Posted By: Mike Hauber
Currently there is quite a significant subsurface warm pool built up in the central Pacific.



Same date 97 shows that el nino development was much further ahead:



However the subsurface warming is a long way ahead of the same stage in development of the 2009 el nino.



From
GEOPHYSICAL RESEARCH LETTERS, VOL 37
“Three Evolution Patterns of Central Pacific El Nino”
Jin -Yi Yu and Seon Tae Kim

“Rather our results confirm that thermocline variations only control the generation of the EP type of SST variability. CP El Nino events can occur in the presence of a deeper- than- normal(ie:recharged state), shallow-than-normal(ie:discharged state) or near-normal(ie, neutral state) thermocline depth....”

I have a question incidental to thermocline depth- I’ve come across a number of references to the shoaling of the mixed layer leading to warming. I had thought of the mixed layer depth as a proxy for thermocline depth and anomously deeper thermocline was indicative of warming(warm Kelvin waves), so shoaling of the mixed layer was synonymous with negative thermocline depth anomly. Anyone able to clarify?

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#1463757 - 13/05/2018 08:38 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: snowbooby]
snowbooby Offline
Weather Freak

Registered: 11/05/2016
Posts: 202
Originally Posted By: snowbooby

I have a question incidental to thermocline depth- I’ve come across a number of references to the shoaling of the mixed layer leading to warming. I had thought of the mixed layer depth as a proxy for thermocline depth and anomously deeper thermocline was indicative of warming(warm Kelvin waves), so shoaling of the mixed layer was synonymous with negative thermocline depth anomly. Anyone able to clarify?


Probably didn’t put the question very well. It may be as simple as a matter of different processes other than upwelling(and cooling) dominating - eg: off equatorial advection, direct heating etc - and thermocline depth anomalies become relatively less important.

Alexander et al (“The Impact of Extratropical Atmospheric Variability on ENSO:Testing the Seasonal Footprinting Mechanism Using Coupled Model Experiments”)have described a (spatial)pathway along which anomalies migrate from the north-eastern sub tropics to the equator.There are definite stages in this journey - the arrival of anomalies at the equator, just one.

The hint being that thermocline depth mightn’t have mattered so much right up to the present time if a modoki nino is to develop - but may become important later.

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#1463876 - 15/05/2018 10:34 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Locke Offline
Weatherzone Addict

Registered: 27/12/2007
Posts: 4478
Loc: Brisbane
Majority of ENSO forecasts through to Summer are for warm neutral. Not a lot of support for an El Nino at the moment.

The models are reactive though. Another solid WWB in the coming month and they might shift towards El Nino whilst an absence of WWB activity will surely slide the forecasts closer to true neutral.
_________________________
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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#1463877 - 15/05/2018 10:40 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
KevD Offline
Occasional Visitor

Registered: 23/09/2001
Posts: 5197
Loc: Bellingen NSW 2454
Always interesting to see what Big Joe has to say - which is some about the upcoming hurricane season and quite a bit about his thoughts on ENSO: https://www.weatherbell.com/may-hurricane-season-update
"Notice the El Niño coming on and a core of warm water off the East Coast. I don't think it will be the kind of hyper El Niño year like 1969 or 2004. Every now and then that happens, but our forecast is in line with weaker Modoki-like El Niño evolutions."

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#1463879 - 15/05/2018 11:11 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Locke]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3302
Loc: Buderim
Originally Posted By: Locke
Majority of ENSO forecasts through to Summer are for warm neutral. Not a lot of support for an El Nino at the moment.



IRI model forecast says 64% chance of el nino, based on model output. It does include quite a number of poor performing models, although EC is a top model showing strong support.

Their expert forecast is more conservative at 49% chance of el nino. This assessment is more recent than the model assessment, but I don't think much has changed in model outlook in the last few weeks.

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#1463881 - 15/05/2018 12:38 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 2609
Loc: Wollongong, NSW, Aus
Meh, they said the same last year....and we all know how that evolved. There is a large slab of warmer sub-surface water, though, and it shall be interesting to see how that manifests.

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#1463885 - 15/05/2018 14:54 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Kino]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3302
Loc: Buderim
Originally Posted By: Kino
Meh, they said the same last year....and we all know how that evolved.


It resulted in claims that the models had been certain of an el nino. They weren't last year, and they aren't this year.

Still the most likely scenario.

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#1463897 - 15/05/2018 19:56 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: snowbooby]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7580
Loc: Adelaide Hills
Originally Posted By: snowbooby
I have a question incidental to thermocline depth- I’ve come across a number of references to the shoaling of the mixed layer leading to warming. I had thought of the mixed layer depth as a proxy for thermocline depth and anomously deeper thermocline was indicative of warming(warm Kelvin waves), so shoaling of the mixed layer was synonymous with negative thermocline depth anomly. Anyone able to clarify?

I'd like to help/find out as well smile , however, perhaps similarly, I'm having rather a lot of difficulty finding a clear literature definition of what "shoaling" means with respect to changes in the thermocline. Shoaling is a term I have not encountered often.


Edited by Seira (15/05/2018 19:56)

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