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#1473829 - 16/10/2018 13:21 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
RC Offline
Weatherzone Addict

Registered: 29/09/2007
Posts: 2340
Loc: near Rockhampton, Qld
I for one will not believe any ENSO forecast beyond a few months.

I have seem them wildly inaccurate that far out, when that time comes up.

There is already a sub surface cool pool poking along slowly.

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#1473830 - 16/10/2018 13:26 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Mike Hauber]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 2617
Loc: Wollongong, NSW, Aus
Originally Posted By: Mike Hauber
I count 9 months on the forecast chart. But there is a good chance that the nino 3.4 index will fall a little below the 0.8 threshold in about 4 to 5 months, so you can call that an end if you want.

I think a real end would be when it falls back below 0, and there is no sign of that happening in the forecast period.

Too late to resize the chart sorry.


Well, we either recognise the official BoM threshold, or we ignore it...can't have it both ways. After 4/5 months on CFS it drops back to warm-neutral. The other model output is way too far out for any reliability (as proven time and time again).

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#1473831 - 16/10/2018 13:39 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3305
Loc: Buderim
El Nino starts when nino 3.4 reaches +ve. Ends when it reaches -ve. It is counted as an el nino if it peaks at 0.8 and above. While others may choose to disagree with these criteria, they are consistent and not a case of trying to have it both ways.

When discussing the impact of the 2009/2010 event BOM refer to the period May to October as the initial phase of the el nino. Nino 3.4 was first +ve in May of that year, and did not reach the threshold of el nino until October.

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#1473832 - 16/10/2018 14:09 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 2617
Loc: Wollongong, NSW, Aus
Originally Posted By: Bom

Bureau of Meteorology, Australia:

"An El Niño has been declared and is underway."
Any three of the following criteria need to be satisfied:
Sea surface temperature: Temperatures in the NINO3 or NINO3.4 regions of the Pacific Ocean are 0.8 °C warmer than average.
Winds: Trade winds have been weaker than average in the western or central equatorial Pacific Ocean during any three of the last four months.
SOI: The three-month average SOI is –7 or lower.
Models: A majority of surveyed climate models show sustained warming to at least 0.8 °C above average in the NINO3 or NINO3.4 regions of the Pacific until the end of the year.


Surely it is erroneous to claim an El Nino simply because SST's push into the +'ve anomalies. No climate monitoring agency uses that threshold.


Edited by Kino (16/10/2018 14:15)

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#1473833 - 16/10/2018 14:30 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3305
Loc: Buderim
There is a difference between claiming an el nino, and determining when it starts/ends. As I already quoted from BOM, BOM stated that the initial phases of the 2009/2010 el nino started in May, which is the same month that nino 3.4 went +ve.

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#1473834 - 16/10/2018 14:55 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 2617
Loc: Wollongong, NSW, Aus
An exception doesnt make the rule. Who knows why they did, but for every other event they’ve taken it from the declaration.

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#1473835 - 16/10/2018 15:08 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3305
Loc: Buderim
Originally Posted By: BOM
During May 2006 to December 2006 (Figure 1), most of Australia was strongly affected by this weak El Niño,


El nino threshold was only reached in November.

When BOM describe el nino impacts they typically consider impacts starting from Autumn, whereas threshold for most el nino events is not reached until Spring. 2009 is not the exception but the rule.

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#1473857 - 16/10/2018 17:50 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: RC]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 7363
Loc: Maffra, Central Gippsland, Vi...
Originally Posted By: RC
I for one will not believe any ENSO forecast beyond a few months.

I have seem them wildly inaccurate that far out, when that time comes up.

There is already a sub surface cool pool poking along slowly.


For what its worth "I for two".

A Nino may be developing now, but if it is, I reckon its only in the mindset of models. Senisble readings to date show neutral conditions in the Pacific right now to me.

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#1473860 - 16/10/2018 17:59 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Petros]
Funkyseefunkydo Offline
Weather Freak

Registered: 30/04/2007
Posts: 690
Loc: East Lake Macquarie
Originally Posted By: Petros
Originally Posted By: RC
I for one will not believe any ENSO forecast beyond a few months.

I have seem them wildly inaccurate that far out, when that time comes up.

There is already a sub surface cool pool poking along slowly.


For what its worth "I for two".

A Nino may be developing now, but if it is, I reckon its only in the mindset of models. Senisble readings to date show neutral conditions in the Pacific right now to me.
So if you’re not using anomalies. What do you base the normal on?

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#1473861 - 16/10/2018 18:12 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 7363
Loc: Maffra, Central Gippsland, Vi...
SST/winds as they are right now in the Pacific (and also around Aus tropics), position of MJO, the equatorial extent of the Humbolt current off Peru and ENSO pressures to name a few. I will be the first to agree with Nino (one is always looming) ....when it actually manifests itself.

....meanwhile Aus is doing OK rainwise.

Re anomolies - yep, I admit to being a total skeptic (cherry picked history date samples). But struggle with how to monitor state of SSL without resorting to Stormsurf site (unless someone has a link to an actual smoothed circa weekly direct reading) - that level is anomoly based.


Edited by Petros (16/10/2018 18:16)

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#1473909 - 17/10/2018 08:14 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3305
Loc: Buderim
Why might the models be forecasting warm/el nino conditions to be long lived?

First the western warm pool is at near record values. Usually western warm pool peaks during the transition from cool ENSO to el nino, and shrinks as El Nino develops and warm water moves into the eastern Pacific. The western warm pool is fuel for future warm Kelvin waves.

However unlike previous periods when western warm pool was very high the warm water is mostly further east towards the dateline, warm pool region, with some cool subsurface in the west. So the western warm pool is better positioned to clear out compared to these past occasions.

Second the North Pacific Meridional mode has been quite firmly in a warm mode, and is currently generating some of the strongest westerly anomalies seen so far at 8 N of the equator. Not a direct impact on ENSO, but makes WWBs along the equator more likely. If this stays in warm mode it will increase the chance of WWBs next Autumn, and oppose the typical La Nina transition mechanism of the NE Pacific high coming further south and increasing trades on the equator.



However the South Pacific Meridional Mode is still in cool mode. It has clearly weakened through the year, but there is currently a renewed burst of trade wind activity. This mode is most important in Spring, so it could make for a late swing towards cool mode if it strengthens (or slow things down now if it strengthens quickly enough)


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#1473910 - 17/10/2018 08:18 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 7363
Loc: Maffra, Central Gippsland, Vi...
Nothing to report from this mornings data, MJO putting itself to sleep over in W Indian (to re-emerge again out that way in a week it seems), Pacific EQ SST typical (above and below surface, and below 0.8C higher than my disputed anomalies), EQ winds in normal trade mode.

I know we are under Nino alert, but if I didnt, I'd call for another 3 weeks of typical October rains for Aus based on the availability of water vapour ingress in from Aus NW & Nth tropical seas.

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#1474028 - Yesterday at 11:31 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
RC Offline
Weatherzone Addict

Registered: 29/09/2007
Posts: 2340
Loc: near Rockhampton, Qld
Interesting the forecast rainfall is like groundhog day in Queensland. The same areas forecast to get it.

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#1474076 - Yesterday at 19:04 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Mike Hauber]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 7363
Loc: Maffra, Central Gippsland, Vi...
Originally Posted By: Mike Hauber
Why might the models be forecasting warm/el nino conditions to be long lived?

First the western warm pool is at near record values. Usually western warm pool peaks during the transition from cool ENSO to el nino, and shrinks as El Nino develops and warm water moves into the eastern Pacific. The western warm pool is fuel for future warm Kelvin waves.

However unlike previous periods when western warm pool was very high the warm water is mostly further east towards the dateline, warm pool region, with some cool subsurface in the west. So the western warm pool is better positioned to clear out compared to these past occasions.

Second the North Pacific Meridional mode has been quite firmly in a warm mode, and is currently generating some of the strongest westerly anomalies seen so far at 8 N of the equator. Not a direct impact on ENSO, but makes WWBs along the equator more likely. If this stays in warm mode it will increase the chance of WWBs next Autumn, and oppose the typical La Nina transition mechanism of the NE Pacific high coming further south and increasing trades on the equator.



However the South Pacific Meridional Mode is still in cool mode. It has clearly weakened through the year, but there is currently a renewed burst of trade wind activity. This mode is most important in Spring, so it could make for a late swing towards cool mode if it strengthens (or slow things down now if it strengthens quickly enough)







Thanks Mike, seems like a "trumpet blast" followed by a .....however to me.

I'm waiting till Monday to see if the modelled WWB above NG becomes reality. If not, will become even more skeptical about the Nino alert (over the next 2 months).

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