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#1473695 - 15/10/2018 10:35 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Locke Offline
Weatherzone Addict

Registered: 27/12/2007
Posts: 4553
Loc: Brisbane
Again check the blue line which is the freezing line. At the times where the volatility exists the temperature is never anywhere close to being above the freezing line.
_________________________
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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#1473696 - 15/10/2018 10:48 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Delta-T Offline
Weather Freak

Registered: 21/01/2011
Posts: 203
Loc: Peachester
I don't think you understand FFDs. If the temp doesn't plunge down you don't get thick ice. The result is a weaker refreeze and thinner ice more prone to melt in summer.


Edited by Delta-T (15/10/2018 10:48)

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#1473697 - 15/10/2018 10:58 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Delta-T]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Originally Posted By: Delta-T
"BTW your chart is in K not C."

"Amazing how on that graph the green line is quite smooth while the red jumps around a bit..."

Bin it?


Not an unsurprising response...

Indicates to me that there's plenty of manipulation and homogenisation (and guesswork) in that data.

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#1473698 - 15/10/2018 11:00 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Delta-T]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Originally Posted By: Delta-T
I don't think you understand FFDs. If the temp doesn't plunge down you don't get thick ice. The result is a weaker refreeze and thinner ice more prone to melt in summer.


And yet the red line stayed below the green which would indicate less summer melt.

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#1473709 - 15/10/2018 11:48 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Kino]
Delta-T Offline
Weather Freak

Registered: 21/01/2011
Posts: 203
Loc: Peachester
"And yet the red line stayed below the green which would indicate less summer melt."

There is that observation depite there being "plenty of manipulation and homogenisation (and guesswork) in that data"?
Can't have it both ways.

That very slightly cooler than normal summer does reduce summer melt but it is only one of many annual factors - like wind events, water temp, salinity, etc. FDD is probably the most important - if you only end up with ice that is half a thick...

Here is the latest:

https://sites.google.com/site/cryospherecomputing/fdd


Edited by Delta-T (15/10/2018 11:51)

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#1473715 - 15/10/2018 12:06 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Quote:
That very slightly cooler than normal summer does reduce summer melt but it is only one of many annual factors - like wind events, water temp, salinity, etc. FDD is probably the most important - if you only end up with ice that is half a thick.


Same rationale applies to the anomalous temps below freezing - doesn't necessarily mean the ice will be thinner.


Edited by Kino (15/10/2018 12:07)

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#1473728 - 15/10/2018 13:09 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Kino]
Delta-T Offline
Weather Freak

Registered: 21/01/2011
Posts: 203
Loc: Peachester
Originally Posted By: Kino
Quote:
That very slightly cooler than normal summer does reduce summer melt but it is only one of many annual factors - like wind events, water temp, salinity, etc. FDD is probably the most important - if you only end up with ice that is half a thick.


Same rationale applies to the anomalous temps below freezing - doesn't necessarily mean the ice will be thinner.


That is not the "same rationale".

I agreed a cooler summer means thicker ice... so a warmer winter is going to "necessarily" mean...thinner ice.


Edited by Delta-T (15/10/2018 13:09)

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#1473729 - 15/10/2018 13:13 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 8071
Loc: Maffra, Central Gippsland, Vi...
Dont know what model stormsurf utilises, but this WWB forecast for next Monday will be of interest to those who are looking for Nino development possibilities:



If this comes to play, it will be interesting to see what the SSL anomoly chart from Stormsurf looks like in 10 days time.

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#1473737 - 15/10/2018 14:13 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Delta-T]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
....and a cooler summer is going to mean thicker ice. Canít have it both ways.

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#1473740 - 15/10/2018 14:41 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Delta-T]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
Originally Posted By: Delta-T
"...tenths of a degree? what is that supposed to tell us ?"

How about 10 or 12 compared to a 60 year average.



Arctic temperature anomaly north of 80 degree from here .
Its not manipulation, its' just a way to flag something odd.


Does this chart have some relevance to Australian drivers? It usually comes up in discussions on climate change...

There are a few tricks in this chart. First the calculation method is based on a spherical projection, and due to distortion of spherical projections near the poles counts the temperature at the north pole as 50% of the final result, and temperature along the 80N ring as the other 50% (i.e. it includes the points 90N-0E, 90N-10E etc which are all actually the same point).

While ice is melting in summer the surface temperature is always pinned to the melting temperature of ice. If more heat is added to the system (more sunshine, more warm winds from the south) then the temperature does not increase but rather more ice melts. If less heat is added (clouds blocking the sun, not much wind from the warmer south) then the temperature does not cool, but rather less ice melts. It is only when the surface becomes completely frozen that temperatures can drop, and it would be only if all the ice melts (which hasn't happened yet) that temps could rise.

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#1473742 - 15/10/2018 14:45 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Petros]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
Originally Posted By: Petros
Dont know what model stormsurf utilises, but this WWB forecast for next Monday will be of interest to those who are looking for Nino development possibilities:

If this comes to play, it will be interesting to see what the SSL anomoly chart from Stormsurf looks like in 10 days time.


Model used is GFS.

Weak as westerlies go, but extends a long way east. Also the trade winds further east while still easterly are forecast to be weaker than normal. Right now trade winds have returned to normal and are forecast to be so for much of the weak. Currently surface temps are neck and neck with 2009, but rapid warming at this stage in 2009 will probably see 2009 take the lead as trade winds return to normal in the next week. After that some significant westerly anomalies forecast so this year might be able to keep close to 2009.

I have noticed that in the Sea level chart there has been a significant expansion towards the east of the highest sea levels in the last couple of weeks - when you first raised this issue the highest sea level ended at 180E, but has now extended a fair way further.

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#1473748 - 15/10/2018 16:03 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Kino]
Delta-T Offline
Weather Freak

Registered: 21/01/2011
Posts: 203
Loc: Peachester
Originally Posted By: Kino
....and a cooler summer is going to mean thicker ice. Canít have it both ways.


WTF? I've stated those very words twice already that that is the case.

I am not the one "wanting both ways". It is your good self that desribed the data as "manipulation and homogenisation (and guesswork)" when you didn't like it, but where happy to suddenly embrace its veracity the moment it looked like it was supporting your opinion.

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#1473749 - 15/10/2018 16:05 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Baloney. Iím merely pointing out that the arguments that there are 2 way to interpret that graph you posted. Anyway, Mike has pretty well debunked your proganda.

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#1473752 - 15/10/2018 16:13 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Delta-T Offline
Weather Freak

Registered: 21/01/2011
Posts: 203
Loc: Peachester
lol, if you say so.


Edited by Delta-T (15/10/2018 16:15)

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#1473760 - 15/10/2018 17:37 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: Mike Hauber]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 8071
Loc: Maffra, Central Gippsland, Vi...
Originally Posted By: Mike Hauber
Originally Posted By: Petros
Dont know what model stormsurf utilises, but this WWB forecast for next Monday will be of interest to those who are looking for Nino development possibilities:

If this comes to play, it will be interesting to see what the SSL anomoly chart from Stormsurf looks like in 10 days time.


Model used is GFS.

Weak as westerlies go, but extends a long way east. Also the trade winds further east while still easterly are forecast to be weaker than normal. Right now trade winds have returned to normal and are forecast to be so for much of the weak. Currently surface temps are neck and neck with 2009, but rapid warming at this stage in 2009 will probably see 2009 take the lead as trade winds return to normal in the next week. After that some significant westerly anomalies forecast so this year might be able to keep close to 2009.

I have noticed that in the Sea level chart there has been a significant expansion towards the east of the highest sea levels in the last couple of weeks - when you first raised this issue the highest sea level ended at 180E, but has now extended a fair way further.


Ta Mike, agree.

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#1473812 - 16/10/2018 10:53 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
Model forecasts are for a long lived el nino event with no end in sight, and almost complete consensus that nino 3.4 will not drop below 0 in the forecast period. Many models (including EC) only forecast to March, which is far too early to rule out a strong drop later in the year, for instance 1998 did not reach -ve values until June. However CFS forecasts out to July, and suggests a small chance of reaching -ve values by July



The Canadian model ensemble, which includes many more models than BOM finds that not one single model forecasts -ve conditions as far out as June, and the multi-model average is still at 0.68, suggesting a second year of el nino conditions. Cool ENSO events that start after June are historically weak, and include last years event and 1983.



Yes predicting at such lead times is tricky, but even at such lead times examples of actual conditions being outside the model forecast range are uncommon (last year, and 2015 out of the last 10 or so years), implying a low chance of genuine La Nina conditions next year.

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#1473815 - 16/10/2018 11:21 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Kino Offline
Weatherzone Addict

Registered: 10/08/2017
Posts: 3505
Loc: Wollongong, NSW, Aus
Can you re-size those graphs please, they're ginormous.

And, surely a 4 or 5 month El Nino isn't that "long-lived with no end in sight".

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#1473816 - 16/10/2018 12:10 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Mike Hauber Offline
Weatherzone Addict

Registered: 13/07/2007
Posts: 3817
Loc: Buderim
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.

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#1473819 - 16/10/2018 12:37 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 8071
Loc: Maffra, Central Gippsland, Vi...
MJO continues to do ever-strengthening circuits around phase1-2 E Indian for the next 10 days or so.

To me, this means the door remains open for moisture ingress into Aus for another 2 weeks (at the least).

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#1473826 - 16/10/2018 13:02 Re: Climate Driver Discussion 2018 (Enso, IOD, PDO ,SAM etc) [Re: ColdFront]
Petros Offline
Meteorological Motor Mouth

Registered: 30/12/2002
Posts: 8071
Loc: Maffra, Central Gippsland, Vi...
...2nd go, its doing laps phase 8-2 W Indian.

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